Myringotomy and Ventilating Tube Insertion

Chronic serous otitis media is common in young children. If untreated or poorly managed, it can lead to hearing loss and formation of cholesteatoma. When conservative medical management fails, surgical drainage of accumulated fluid in the middle ear is indicated. Myringotomy creates an opening in the tympanic membrane through which fluid can drain. If performed alone, when the incision heals, the drainage path is occluded. Therefore myringotomy is frequently accompanied by placement of a ventilation tube. A small plastic tube (a variation of the grommet or the T-tube) inserted in the tympanic membrane serves as a stent for the ostium, facilitating continuous drainage from the middle ear until the tubes are naturally extruded in 6 months to a year, or surgically removed at an appropriate time.

Children with cleft palate have a high frequency of middle ear disease compared with the noncleft population, because of associated abnormalities of the cartilage and muscles surrounding the eustachian tubes. Surgical drainage and ventilation tube insertion is a standard treatment for chronic otitis media in these children. This is usually performed at the time of the surgical repair of the cleft.

Most young children require general anesthesia for tympanotomy tube placement, although an occasional older child may tolerate topical anesthesia. This may be accomplished by iontophoresis or instillation of lidocaine–prilocaine cream (EMLA cream), which remains in the ear canal for an hour and is then suctioned out before the procedure.

Myringotomy with tube insertion is a very brief operation, usually performed as ambulatory surgery using a potent inhalational agent (e.g., sevoflurane), oxygen, and nitrous oxide administered by facemask with spontaneous respirations. An oropharyngeal airway may assist in maintaining a patent airway when the head is laterally rotated and reduces head movement (which is amplified through the microscope). Gentle manual assistance of ventilation can also help reduce head movement. Occasionally, a laryngeal mask airway (LMA) may be used in children in whom the procedure is expected to be prolonged (e.g., children with narrow ear canals) or those with a difficult airway. Most children can be managed safely without intravenous (IV) access,³ but it is reasonable to have an IV setup ready. Some children with severe underlying medical or surgical conditions will require IV access, despite the anticipated brief duration of the minor procedure. Although premedication is often omitted because their duration of action exceeds that of the procedure, an anxious child may still benefit from a sedative premedication.

In some instances, it is desirable to remove a retained tympanostomy tube. This can be easily accomplished in the surgeon’s office without anesthesia. Some stiff-flanged grommet tubes require general anesthesia for removal. If the incision does not heal spontaneously, a paper patch or fat graft may have to be placed to stimulate healing of the tympanic membrane. The anesthetic would be the same as that for the tube placement, except that nitrous oxide is best avoided to minimize the chance of graft dislodgment (see later discussion).

Discomfort after myringotomy and tube insertion is usually managed by the administration of acetaminophen, either via the oral route preoperatively or the rectal route intraoperatively. The recommended dose of acetaminophen to achieve therapeutic blood levels is 10 to 20 mg/kg when administered via the oral route, and 30 to 40 mg/kg when administered via the rectal route.^4–7 Oral acetaminophen is very rapidly absorbed, achieving therapeutic blood levels in minutes, whereas rectal acetaminophen is slowly absorbed, with a time to onset of action of 60 to 90 minutes, and a time to peak effect of 1 to 3 hours.^8–11 Consequently, the oral route is preferred for this procedure.

Preschool-aged children who receive sevoflurane without an analgesic for myringotomy and tube insertion may exhibit emergence delirium and postoperative agitation (see Chapter 4). Although pain may be partially responsible for these responses, their etiologies are not completely understood. Because the procedure is so brief and IV access is not usually established, intranasal fentanyl, 1 to 2 µg/kg, has been shown to provide analgesia and to reduce the frequency of emergence agitation.^12,13 The only significant side effect is a 12% incidence of vomiting when oral fluids are administered in the early postoperative period.⁵ Other medications, including IV ketorolac (1 mg/kg), or intranasal butorphanol (25 µg/kg), and intranasal dexmedetomidine (1 to 2 µg/kg), have been shown to reduce the pain after myringotomy and tube insertion.^14–16 However larger doses of dexmedetomidine (2 µg/kg) significantly prolong the duration of stay in the postanesthesia care unit (PACU). Some practitioners prefer to use more soluble anesthetics, such as isoflurane, for anesthesia maintenance to reduce the incidence of agitation after myringotomy and tube insertion, although there is limited evidence to support this practice.

Children with chronic otitis frequently have persistent rhinorrhea and suffer recurrent upper respiratory tract infection (URI) (see Chapter 11). Eradication of middle ear congestion and improved fluid drainage often resolves the concomitant symptoms. The frequency of perioperative complications in children with mild URIs is similar to that in children who are asymptomatic. In general, morbidity is not increased in children who present for minor surgery with acute uncomplicated mild URIs, provided tracheal intubation can be avoided.^17,18 Canceling this surgery because of rhinorrhea or recurrent mild respiratory symptoms is not usually justifiable. It is, however, recommended that children with respiratory symptoms have their oxygen saturation measured before induction of general anesthesia, and that supplemental oxygen is administered postoperatively to those whose oxygen-saturation readings are less than 93%.¹⁹

Middle Ear and Mastoid Surgery

Tympanoplasty and mastoidectomy are two of the most common major ear operations performed in children. General anesthesia usually consists of an inhalational anesthetic and IV opioids. Surgical identification and preservation of the facial nerve are necessary because of its proximity to the surgical field. To ensure the facial nerve can be identified using electrical stimulation, neuromuscular blockade is usually avoided. If a muscle relaxant must be used, a small dose should be given to facilitate tracheal intubation; if a muscle relaxant is used for maintenance, suppression of the twitch response should not exceed 70%.

To gain access to the surgical site, the child’s head is placed on a headrest, which may be positioned below the operating table. In addition, extreme degrees of lateral rotation may be required to visualize the middle ear anatomy. The anesthesiologist and surgeon must be especially vigilant to ensure that nerves, muscles, and bony structures are not injured as a result of this unusual positioning; the sternocleidomastoid muscles generally limit the safe degree of lateral head rotation. Left or right tilting (airplaning) of the operating room (OR) table minimizes the need for extreme lateral head rotation as in the case of children with Down syndrome. The laxity of the ligaments of the cervical spine, as well as immaturity of the odontoid process in these children predisposes them to C1-C2 subluxation. Of children with Down syndrome or achondroplasia, 15% to 31% have atlantoaxial instability.^20–23 Anteroposterior positioning requires the utmost care to avoid injury. Positioning of the OR table to allow access to the respective middle ear and accommodate all the extra surgical equipment can also pose a challenge. Depending on the room configuration, the table may be rotated 90 degrees or even 180 degrees away from the anesthesia machine, necessitating the use of extra-long breathing circuits (Fig. 31-1). As a result of the limited access to the airway, very careful attention must be paid to securing the tracheal tube. Draping must allow immediate access to the airway should that be required.

FIGURE 31-1 An operating room table turned 180 degrees may limit access to the child during ear surgery. ESU is the electrosurgical unit.

Bleeding must be kept to a minimum during surgery on the small structures of the middle ear. Relative hypotension (i.e., mean arterial pressure 10% to 25% less than baseline) may help to reduce bleeding. Concentrated epinephrine solution, 1 : 8000, is frequently applied to the tympanic membrane to induce vasoconstriction of the blood vessels. Close attention should be paid to the dose of epinephrine used to avoid arrhythmias and wide swings in blood pressure. The maximum dosage of topical epinephrine is 10 µg/kg, which may be repeated after 30 minutes.

The middle ear and sinuses are air-filled, nondistensible cavities. An increase in the volume of gas within these cavities increases the pressure within the cavities. Nitrous oxide diffuses along a concentration gradient into air-filled middle ear spaces more rapidly than nitrogen moves out because nitrous oxide is 34 times more soluble in blood than nitrogen. The middle ear is vented through the opening of the eustachian tube. Normal passive venting of the eustachian tube occurs at 20 to 30 cm H₂O pressure. Nitrous oxide increases the pressures within the middle ear such that they exceed the ability of the eustachian tube to vent the middle ear within 5 minutes, leading to pressure buildup.²⁴ If the function of the eustachian tube is compromised during the surgical procedure, then pressure in the middle ear can increase further. Venting the middle ear occurs intermittently, and leads to constant fluctuations in middle ear pressure that cause movement of the tympanic membrane.²⁵ During procedures in which the tympanic membrane is replaced or a perforation is patched, nitrous oxide should be discontinued or, if this is not possible, limited to a maximum of 50% of the concentration before the application of the tympanic membrane graft to reduce the potential for pressure-related displacement.²⁶ The omission of nitrous oxide does not significantly increase the requirements (minimal alveolar concentration) for the less-soluble inhaled anesthetics, desflurane, or sevoflurane in children.²⁷ After nitrous oxide is discontinued, it is quickly reabsorbed, creating a void in the middle ear, with resulting negative pressure. This negative pressure may result in serous otitis, disarticulation of the ossicles in the middle ear (especially the stapes), and hearing impairment, which may last up to 6 weeks postoperatively. The use of nitrous oxide may increase the incidence of postoperative nausea and vomiting (PONV), as a direct result of negative middle ear pressure during recovery. The negative pressure created by the reabsorption of nitrous oxide stimulates the vestibular system by producing traction on the round window. Although all children are at risk for PONV, older children and adolescents, in particular, seem to be at greatest risk.²⁸ Prophylactic administration of antiemetics (e.g., dexamethasone and ondansetron) is usually warranted. Local infiltration of the great auricular nerve can provide pain relief equivalent to that of opioids and may reduce the incidence of opioid-induced vomiting (see Chapter 41).²⁹

A smooth, quiet emergence is desirable. Deep tracheal extubation can be accomplished if the child breathes spontaneously during the last 15 to 20 minutes of surgery, the concentration of inhalational anesthetic is greater than 1.3 times the minimal alveolar concentration, and opioids are titrated to produce regular slow respirations. Gentle suctioning of the oropharynx and possibly the use of IV lidocaine (1 to 1.5 mg/kg) in children older than 1 year of age can minimize or even prevent coughing after the tracheal tube is removed.

Cochlear Implants

In recent years, the indications for cochlear implants have broadened and continue to evolve. With the application of universal neonatal hearing screening programs, a large pool of hearing-impaired infants has been identified. The benefits of early intervention with cochlear implants are being explored. Younger children with severe to profound hearing loss markedly improve their auditory, speech, and language skills after cochlear implants, and more of these children can be mainstreamed with their age-appropriate hearing peers when they receive an implant early in life. Experience has shown that cochlear implant surgery is safe in infants older than 6 months of age, provided that special attention is paid to the physiologic and anatomic differences present in this age-group. Surgery requires meticulous care with hemostasis, soft tissue dissection, and bone drilling because bleeding from bone can be difficult to control and can complicate the surgical outcome. Availability of skilled postoperative nursing and a pediatric intensive care unit (ICU) is also essential.³⁰ Postoperative fitting of the externally worn speech processor is very important for successful use of the cochlear implant. However, this fitting process can be difficult, particularly in infants and young children, because of limited communication capabilities. Stapedius reflex thresholds obtained intraoperatively have been used for postoperative speech processor fitting, although the influence of anesthetics on the threshold values must be taken into account. More reliable threshold values can be obtained by adjusting the dosage of hypnotics to achieve a lighter level of hypnosis during stapedius reflex measurement.³¹ In most children, increasing the concentration of inhalational anesthetics increases the stapedius reflex threshold. As always, appropriate communication with the surgeon will help ensure a successful outcome.

Preoperative Evaluation

The general health of the child and the indications for surgery must be reviewed. URIs are frequent in these children and can interfere with the timing of adenotonsillectomy because the risk of respiratory morbidity and hemorrhage is increased.^46,51,58,59 A history of bleeding tendencies requires investigation. Medications that interfere with coagulation include aspirin, NSAIDs, and valproic acid. Discontinuation of these drugs preoperatively is sometimes problematic, and preoperative consultation with neurology, cardiology, and hematology specialists may be indicated.

A careful cardiorespiratory history and physical examination is essential. Children with chronic tonsillar hypertrophy may have long-standing hypoxemia and hypercarbia, which can lead to cor pulmonale (see Fig. 31-2). The oropharynx should be evaluated and the tonsillar size classified (Fig. 31-3).⁶⁰ In some centers, a complete blood cell count is required before adenotonsillectomy. There is no evidence that routinely performed preoperative coagulation studies are beneficial unless they are indicated by history.^61,62 The indications for the procedure should be clearly delineated. If the indication is for obstructed breathing, then further evaluation for symptoms of possible obstructive sleep apnea (OSA) is indicated. Parents should be asked if the child snores loudly, if the snoring can be heard through a closed door, if there are gasps or pauses in respirations, if there is daytime somnolence, night terrors, nocturnal enuresis, attention deficit disorder, or poor school performance. A positive response to any of these questions is suggestive of OSA, in particular when combined with obesity (weight greater than the 95th percentile).^63–67

FIGURE 31-3 Classifying tonsil size may be helpful in evaluating the degree of airway obstruction. Children classified as +3 or greater (i.e., having more than 50% of the pharyngeal area occupied by hypertrophied tonsils) are at an increased risk of developing airway obstruction during anesthetic induction.

(Modified from Brodsky L. Modern assessment of tonsils and adenoids. Pediatr Clin North Am 1989;36:1551-69; illustration by Jon S. Krasner.)

Special Considerations for the Child with OSA

The single most important task during the preoperative evaluation of the child for adenotonsillectomy is to distinguish the child with OSA from the child with obstructive breathing, because the former is at greater risk for developing severe perioperative respiratory complications, possibly including death, after adenotonsillectomy.68–71b

OSA is the most severe form of sleep-disordered breathing. Sleep-disordered breathing ranges from normal respirations to primary snoring, upper airway resistance syndrome (UARS), obstructive hypopnea, and OSA. At the most extreme form of sleep-disordered breathing, OSA, clinical signs of partial or complete upper airway obstruction (UAO) must be present during sleep, as well as some degree of hypercarbia and/or hypoxemia.⁷² Although it is important to recognize the significance of OSA in children who are scheduled for adenotonsillectomy, children who do not meet the criteria for OSA but who have less severe forms of sleep-disordered breathing, such as UARS or obstructive hypopnea, may also be at increased risk for morbidity after surgery. Guidelines for the perioperative management of these children continue to be developed.^71a,73,74

A high index of suspicion is required to identify the child with OSA on clinical criteria, although clinical criteria do not distinguish primary snoring from OSA in children.⁷⁵ There is a greater incidence of OSA in Asian and African American populations.^76,77 In addition, African American children desaturate more profoundly during sleep-related obstructive airway events than do Caucasian and Hispanic children⁷⁸; the reason for this difference is unclear.

Anatomic features, including increased nasal resistance, may underlie the pathogenesis of OSA; common medical conditions and syndromes that predispose to the development of OSA are listed in Table 31-2. Infants suffering acute life-threatening events have a greater incidence of OSA in childhood and adolescence.^79–81

TABLE 31-2 Medical Conditions in Children That Predispose to Development of Obstructive Sleep Apnea

Craniofacial Syndromes

Crouzon syndrome

Apert syndrome

Pfeiffer syndrome

Treacher Collins syndrome

Pierre Robin sequence

Goldenhar syndrome

Larsen syndrome

Disorders of Cranial Base

Arnold-Chiari malformation

Achondroplasia

Syringobulbia

Neuromuscular Disorders

Cerebral palsy

Trisomy 21

Infiltrative Disorders

Mucopolysaccharidoses

Acromegaly

Obesity

Prader-Willi syndrome

Temporomandibular Joint Ankylosis

The obstructive events that characterize OSA result in recurrent episodes of hypoxia, hypercarbia, and sleep disruption, a trilogy that has been linked to the development of medical sequelae that accompany severe OSA. Because adenotonsillectomy is very often the initial treatment for the majority of children, these children may present with a spectrum of disease affecting multiple organ systems. Failure to thrive is common. Cardiovascular abnormalities, including ventricular dysfunction, a depressed ventricular ejection fraction, right ventricular hypertrophy, and pulmonary hypertension, may be present.^82–85 Repeat infections affecting the lower respiratory tract have been linked to chronic aspiration.⁸⁶

The severity of OSA is assessed by the frequency and severity of the obstructive respiratory events during sleep; both vary with sleep stage and occur most often during rapid eye movement (REM) sleep. The frequency and severity of obstructive events worsen after midnight, a finding that may reflect the greater proportion of REM sleep in the latter part of the night and fatigue of the upper airway musculature.^87–89

Apneas are classified as central, obstructive, and mixed. Central apnea occurs when there is no apparent respiratory effort. Obstructive apnea is associated with apparent, often vigorous, inspiratory efforts that are ineffective because lack of upper airway patency. A mixed obstructive apnea is diagnosed when both central and obstructive apnea occur without interruption by effective respirations. The presence of sleep-disordered breathing is documented by polysomnography and is quantitated by the frequency of obstructive events and by oxygen-desaturation indices. The polysomnogram simultaneously records the electroencephalogram, electromyogram, electrocardiogram, pulse oximetry, airflow, and thoracic and abdominal movement during sleep. A recent consensus paper on the criteria for diagnosing OSA in children has been developed.^71a,84 A common definition of obstructive apnea in children is an obstructive effort that includes more than two obstructive breaths, regardless of the duration of the apnea.⁸⁷ An obstructive apnea index of 1 is the cutoff for normality in children.⁹⁰ Hypopnea is defined as a reduction in airflow of more than 50%.⁸⁷ The apnea hypopnea index (AHI) is the summation of the number of obstructive apnea and hypopnea events and is analogous to the respiratory disturbance index (RDI). A common definition of desaturation is a 4% decrease in oxygen saturation from baseline. The saturation nadir is the minimum oxygen saturation recorded during the sleep study. A saturation nadir of 92% is the minimum normal saturation in children.^90,91

The severity of OSA predicts the nature of perioperative respiratory complications (Table 31-3). An RDI of greater than 20 events per hour is associated with breath holding during induction, whereas an RDI greater than 30 is associated with laryngospasm and desaturation during emergence.⁹² Ten obstructive events per hour during a screening polysomnogram is the threshold for severe postoperative respiratory complications.⁶⁹ An oxygen-saturation nadir less than 80% is associated with a greater incidence of respiratory morbidity after adenotonsillectomy, compared with a saturation nadir greater than 80%.^68,71

TABLE 31-3 Clinical Diagnostic Criteria for Pediatric Obstructive Sleep Apnea Syndrome

1. Predisposing physical characteristics

a. Body mass index greater than 95th percentile for age and gender

b. Craniofacial abnormalities affecting the airway

c. Anatomic nasal obstruction

d. Tonsils nearly touching or touching in the midline

2. History of apparent airway obstruction during sleep (two or more of the following)

a. Loud snoring (loud enough to be heard through a closed door)

b. Frequent snoring

c. Observed pauses in breathing during sleep

d. Frequent arousals from sleep

e. Intermittent vocalization during sleep

f. Parental report of restless sleep, difficulty breathing, or struggling respiratory efforts during sleep

g. Nocturnal enuresis

3. Somnolence (one or more of the following)

a. Parent or teacher comments that the child appears sleepy during the day, is easily distracted, is overly aggressive, or has difficulty concentrating

b. Child often is difficult to arouse at the usual awakening time

Note: If signs and symptoms in at least two categories are present, there is a significant probability of moderate obstructive sleep apnea (OSA). If severe abnormalities are present, children should be treated as having severe OSA.

Modified from Table 1 in Gross JB, Bachenberg KL, Benumof JL, et al. Practice guidelines for the perioperative management of patients with obstructive sleep apnea: a report by the American Society of Anesthesiologists Task Force on Perioperative Management of patients with obstructive sleep apnea. Anesthesiology 2006;104:1081-93.

The RDI and AHI correlate inversely with the oxygen-saturation nadir,^93,94 making simplified testing with continuous pulse oximetry a meaningful metric. The McGill oximetry score has been shown to correlate with the risk of respiratory complications after adenotonsillectomy in children (Fig. 31-4). Of children with a McGill oximetry score of 4, 24% experienced major postoperative respiratory complications.⁹⁴

FIGURE 31-4 Representative figures for McGill oximetry scores 1 to 4 (top to bottom). McGill oximetry scores 2 to 4 are abnormal in that they all show at least three clusters of desaturation. The severity of the saturation nadir determines the score such that McGill oximetry scores 2, 3, and 4 correspond to saturation nadirs of less than 90%, less than 85%, and less than 80%, respectively.

(From Nixon GM, Kermack AS, Davis GM, et al. Planning adenotonsillectomy in children with obstructive sleep apnea: the role of overnight oximetry. Pediatrics 2004;113:e19-25.)

Children with severe OSA may require additional preoperative testing before adenotonsillectomy. A capillary blood gas sample drawn in the morning can be evaluated for an increased concentration of bicarbonate, suggestive of CO₂ retention during sleep. When indicated, a preoperative electrocardiogram or echocardiogram may provide evidence of right ventricular hypertrophy and/or pulmonary hypertension. A chest radiograph may suggest lower airway disease or cardiomegaly.

Consultations to plan the perioperative care of children with severe OSA are important. Young children with profound oxygen desaturation during sleep and CO₂ retention may require admission to the pediatric ICU for optimization before and/or after adenotonsillectomy.^36,94 Urgent adenotonsillectomy for severe OSA is associated with significant respiratory morbidity after surgery.^70,95 On occasion, adenotonsillar hypertrophy may progress to compromise the upper airway during wakefulness. In some instances the anesthetic considerations for the obstructed and difficult airways may overlap.

Anesthetic Management and Postoperative Considerations

The anesthetic goals for adenotonsillectomy are (1) to provide a smooth, atraumatic induction; (2) to provide the surgeon with optimal operating conditions; (3) to establish IV access for volume expansion and medications as indicated; and (4) to provide rapid emergence so that the child is awake and able to protect the recently instrumented airway. The need for a premedication is determined during the preanesthetic evaluation. Children with symptoms of sleep-disordered breathing who require premedication should be closely observed, although the desaturation is transient and infrequent (1.5% of cases) after oral midazolam premedication.⁹⁶ Monitoring with pulse oximetry after premedication may be indicated for select children with severe OSA and confounding variables.⁹⁶ Premedication with short-acting drugs and/or those that can be antagonized is advised (see further).

The anesthetic techniques for adenotonsillectomy are varied and include the choice of an inhalational or IV technique, the choice of an ETT or LMA, and the choice of spontaneous or controlled ventilation. Of the currently available inhalational agents, sevoflurane provides a smooth induction of anesthesia, and desflurane (for those whose airway is secured with an ETT) used for maintenance provides a rapid emergence and recovery.^97,98 The rapid return of airway reflexes is particularly important when the dose of opioids must be titrated after extubation.

Children who are scheduled for adenotonsillectomy have a high incidence of airway reactivity and laryngospasm. This will influence the choice of airway management. Placement of an oral RAE or standard uncuffed ETT with a leak at 20 cm H₂O (the leak increases with neck extension and insertion of the mouth gag) is generally sufficient to prevent soiling of the trachea during the surgery, yet reduces the incidence of postextubation croup. Cuffed ETTs have become increasingly used in children of all age-groups.⁹⁹ A cuffed tube prevents an air leak and the consequent bubbling of gases through the oropharyngeal secretions and blood that can interfere with surgery. It also minimizes pollution by anesthetic gases and decreases the risk of an airway fire when electrocautery is used.

Blood and secretions may be present in the oropharynx at the conclusion of surgery and should be carefully suctioned before emergence from anesthesia. Emptying the stomach with an orogastric tube, a maneuver frequently performed by the surgeon under direct vision after completion of surgery, does not reduce the incidence of PONV, although the study was underpowered to detect a difference.¹⁰⁰

It is preferable to wait until the child is fully awake and able to clear blood and secretions from the oropharynx before removing the ETT. A common practice is to position the child in the lateral position (known as the “tonsil” or “recovery” position) with the head slightly down at the time of extubation to permit blood and secretions to pool in the dependent cheek and drain out of the mouth rather than accumulate at the laryngeal inlet. Intact airway and pharyngeal reflexes are of utmost importance in preventing aspiration, laryngospasm, and airway obstruction.¹⁰¹ The child should remain in the tonsil position postoperatively, while being carefully observed and monitored during transport to the recovery room.

The use of the LMA for adenotonsillectomy was described in 1990, but it was not until the widespread availability of a model with a flexible spiral, metallic reinforced shaft that it was widely used (E-Fig. 31-1).^102,103 The wide, rigid tube of the original model did not fit under the mouth gag and was easily compressed or dislodged during full mouth opening. The newer, flexible model has a soft, reinforced shaft, which easily fits under the mouth gag without becoming dislodged or compressed. Adequate surgical access can be achieved and the airway is reasonably well protected from exposure to blood during the surgery.^104,105 Early advantages cited for the LMA over the ETT include a decrease in the incidence of postoperative stridor and laryngospasm, and an increase in immediate postoperative oxygen saturation,¹⁰⁶ although recent evidence disputes any difference in the frequency of laryngospasm.¹⁰⁷ Insertion of the LMA, however, may be difficult in the presence of tonsillar enlargement, and careful placement to avoid kinking of the LMA is essential.¹⁰⁸ Although it has been recommended that the LMA be used only in spontaneously breathing children and that positive-pressure ventilation be avoided, gentle assisted ventilation is both safe and effective if peak inspiratory pressure is limited to 20 cm H₂O or less. If there is any leak of gases around the LMA then the potential for an airway fire must be considered and appropriate precautions taken if electrocautery is used.

E-FIGURE 31-1 Laryngeal mask airway made for ear, nose, and throat surgery.

Analgesic Management

Surgical technique has a major impact on the analgesic requirements after adenotonsillectomy because electrocautery techniques are generally associated with greater pain, presumably owing to increased thermal injury,^40,41,109 although this is debated.¹¹⁰ Opioids have been the mainstay of perioperative analgesia. However, because opioids increase the incidence of emesis¹¹¹ and respiratory morbidity, the use of opioid-sparing adjuncts has been advocated, including dexamethasone, acetaminophen, NSAIDs, and ketamine.

A single intraoperative dose of dexamethasone reduces postadenotonsillectomy pain and edema when electrocautery has been used. Large doses are traditionally used, especially in children with OSA. Dexamethasone (1 mg/kg) administration is associated with reduced parental- and physician-rated pain scores after adenotonsillectomy (Table 31-4).⁴¹ The minimum morphine-sparing dose for dexamethasone is reported to be 0.5 mg/kg.¹¹² For dexamethasone doses between 0.0625 mg/kg and 1.0 mg/kg, the frequency of postoperative vomiting, pain scores, and times to first liquid and first analgesics were similar.¹¹³ A similar absence of a dose response for dexamethasone between 0.050 and 0.15 mg/kg for vomiting after tonsillectomy was reported in another study.¹¹⁴ Single doses of dexamethasone have not been associated with aseptic necrosis of the hip or infections, but have been responsible for several cases of acute tumor lysis syndrome, including one death.^115–117 One study suggested an increased risk of bleeding after tonsillectomy in children who received dexamethasone up to 0.5 mg/kg (maximum 20 mg).¹¹⁸ These findings have been refuted by a recent meta-analysis and several studies.^119–122a

TABLE 31-4 Effect of Single Intraoperative Dose of Dexamethasone on Postoperative Pain in Pediatric Tonsillectomy or Adenotonsillectomy: A Comparison of Randomized, Double-Blind Studies

The routine use of NSAIDs for adenotonsillectomy remains controversial because of the potential for postadenotonsillectomy hemorrhage. A meta-analysis of seven randomized controlled trials (505 children) on the effects of NSAIDs on bleeding risk after tonsillectomy reported the number needed to harm, in terms of reoperation for hemostasis, to be 29.¹²³ NSAIDs were associated with a greater risk of both postoperative bleeding that required treatment and reoperation for hemostasis. The Cochrane Collaboration assessed the effect of NSAIDs on bleeding after pediatric tonsillectomy in 13 trials (955 children) and found no increase in bleeding that required reoperation for hemostasis.¹²⁴ An audit of more than 4800 pediatric tonsillectomies in which the NSAIDs diclofenac and ibuprofen were routinely used, reported a primary hemorrhage rate of 0.9%.⁵⁵ Because the effects of ketorolac on platelet function are reversible, the effect is dependent on the presence of ketorolac within the body.¹²⁵ Thus, unlike the effect of aspirin, this effect is short-lived. However, we recommend administering NSAIDs only after consulting with the surgeon and, if in agreement, administering them after hemostasis is achieved.¹²⁶ Acetaminophen is commonly used as a component of multimodal analgesic approach in these children.¹²⁷ IV formulations of acetaminophen are now available in many countries, offering the theoretical advantage of greater predictability than the oral and rectal routes. However, recent studies suggest that the duration of analgesia after 15 mg/kg of acetaminophen given IV is less than that after 40 mg/kg given rectally.¹²⁸ Furthermore, although introduced only 7 years ago, two reports of 10-fold overdoses of IV acetaminophen with near-catastrophic outcomes in infants should alert clinicians to the very serious risk of dosage errors with this medication.¹²⁹

An IV infusion of dexmedetomidine 2 µg/kg over 10 minutes followed by 0.7 µg/kg/hr combined with an inhalation agent can provide satisfactory intraoperative conditions for adenotonsillectomy without adverse hemodynamic effects. In children with OSA syndrome, postoperative opioid requirements are significantly reduced and the incidence and severity of severe emergence agitation is reduced, with few children desaturating.¹³⁰ After larger doses of dexmedetomidine (2 and 4 µg/kg), the opioid-free interval increases and the postoperative opioid requirements decrease. However, duration of stay in the PACU is prolonged.¹³¹

Infiltration of local anesthetics into the tonsillar fossa during tonsillectomy is sometimes reported to decrease postoperative pain, but the pain relief is transient (E-Fig. 31-2).¹³² In addition, life-threatening complications have been reported after local anesthetic infiltration in the tonsillar fossa, including intracranial hemorrhage, bulbar paralysis, deep cervical abscess, cervical osteomyelitis, medullopontine infarct, and cardiac arrest. The risks associated with injection of local anesthesia in the tonsillar fossa may outweigh its potential benefits, particularly in inexperienced hands.^133,134

E-FIGURE 31-2 Tonsillar infiltration.

Postoperative Nausea and Vomiting

Emesis and poor oral intake are common comorbid conditions after adenotonsillectomy. Opioids increase the incidence of PONV, with two thirds of treated children experiencing PONV.^37,55,135 The incidence of PONV increases with morphine dose.^111,136 Propofol infusions,^136a,136b ondansetron and dexamethasone are widely used to reduce the incidence of emesis after adenotonsillectomy. Postdischarge vomiting continues for days in some children. One study has shown that at-home use of oral ondansetron disintegrating tablets may prevent emesis during the first 3 days after adenotonsillectomy.¹³⁷ A single intraoperative dose of dexamethasone reduces the incidence of emesis during the first 24 hours after adenotonsillectomy.¹³⁸ The number of children needed to treat was only four, which means that the use of dexamethasone in four children undergoing adenotonsillectomy results in one less child experiencing PONV. In addition, children who received dexamethasone were more likely than those receiving placebo to advance to a soft diet on postoperative day 1, with a number needed to treat of five. Given the antiemetic and possible morphine-sparing advantages of a single dose of dexamethasone, and its low cost and safety profile, the evidence suggests that routine use of dexamethasone reduces morbidity after adenotonsillectomy in children.^41,138 Although the literature supports the effectiveness of a single dose of dexamethasone, the smallest effective dose remains somewhat unclear. One study suggested an IV dose of 0.15 mg/kg,¹³⁹ whereas another reported no difference in postoperative vomiting, pain scores, time to first liquid, and time to first analgesics between doses of 0.0625 and 1.0 mg/kg (Fig. 31-5).¹¹³ Acupuncture, acupressure, as well as therapeutic suggestion, have also been used with variable results.^140–142

FIGURE 31-5 No dose-escalation response to dexamethasone to prevent vomiting in children undergoing tonsillectomy. Time-to-event analysis for first vomiting episode was performed; tick marks indicate time of censoring for patients who did not have complete follow-up (N = 13). No significant difference was found between dose levels, P = 0.28 (Cox Proportional Hazard Likelihood Ratio Test).

(Redrawn with permission from Kim MS, Coté CJ, Cristoloveanu C, et al. There is no dose-escalation response to dexamethasone (0.0625-1.0 mg/kg) in pediatric tonsillectomy or adenotonsillectomy patients for preventing vomiting, reducing pain, shortening time to first liquid intake, or the incidence of voice change. Anesth Analg 2007;104:1052-8.)

Special Considerations for Children with OSA

Children with OSA who require premedication should be closely observed, because transient oxygen desaturation has been reported in 1.5% of children with OSA who received 0.5 mg/kg oral midazolam.⁹⁶

Induction of Anesthesia

Compared with children undergoing adenotonsillectomy for chronic tonsillitis, those whose indication was OSA experienced more respiratory complications during induction of anesthesia.⁹² The vulnerability of the upper airway musculature described for halothane¹⁴³ has subsequently been reported for most anesthetic agents, resulting in a graded reduction in airway caliber with increasing anesthetic concentration.^144–148 Airway obstruction occurs in the upper two thirds of the pharyngeal airway, and the smallest pharyngeal dimension is in the area of overlap between the adenoids and tonsils.¹⁴⁷ During induction of anesthesia, early pharyngeal airway obstruction may require a jaw thrust maneuver, insertion of an oral or nasopharyngeal airway, and the application of continuous positive airway pressure (CPAP). Propofol-associated loss in airway caliber is reversed with the application of CPAP.¹⁴⁸ CPAP acts as a pneumatic splint to increase the caliber of the pharyngeal airway (Fig. 31-6).¹⁴⁹ Of equal importance, CPAP increases longitudinal tension on the pharyngeal airway, thereby decreasing the collapsibility of the upper airway (see Fig. 12-10), and increases lung volumes.^150,151 Small increments in CPAP between 5 and 10 cm H₂O increase the dimension of the pharyngeal airway dramatically (Fig. 31-7).^152,153 The closing pressure of the pharynx increases with OSA severity, such that greater levels of CPAP are required in children with severe OSA compared with those with mild OSA. It is prudent to consider securing IV access before induction of anesthesia in children with severe OSA, to expedite administration of muscle relaxants or IV agents should pharyngeal obstruction or laryngospasm occur during induction. The small oropharynx and adenotonsillar hypertrophy associated with severe OSA may increase the difficulty in properly inserting an LMA.

FIGURE 31-6 When a child has upper airway obstruction caused by laryngospasm (A) or mechanical obstruction (B), application of approximately 10 cm H₂O of positive end-expiratory pressure (PEEP) during spontaneous breathing often relieves obstruction. PEEP helps to hold the vocal cords apart (A) and the airway open (broken lines in B).

(From Coté CJ. Pediatric anesthesia. In Miller RD, editor. Miller’s anesthesia. 8th ed. New York: Churchill Livingstone; 2012. In press.)

FIGURE 31-7 The relationship between airway pressure and the cross-sectional area of the pharynx. Maximal airway dimension is achieved between 15 and 20 cm H₂O. At reduced airway pressures, around 5 cm H₂O, small increments in airway pressure make a large difference in airway caliber.

(From Isono S, Tanaka A, Nishino T. Dynamic interaction between the tongue and soft palate during obstructive apnea in anesthetized patients with sleep-disordered breathing. J Appl Physiol 2003;95:2257-64.)

Analgesic Management in Children with OSA

Severe OSA is characterized by recurrent episodes of transient hypoxia and hypercarbia during sleep. In animal models, exposure to intermittent hypoxia during development affects the opioid system, increasing the density of µ-opioid receptors in the respiratory-related areas of the brainstem. The cellular mechanism whereby this increased density is achieved has yet to be elucidated, but it may represent an adaptive response to the effects of recurrent intermittent hypoxia that allows µ-receptor–mediated opioid respiratory effects to predominate.^154–157

For children with severe OSA, the severity of the nocturnal oxygen desaturation correlates with the sensitivity to exogenously administered opioids (Fig. 31-8).^158–160 The morphine dose required to achieve a uniform analgesic endpoint in children with OSA who exhibited a low preoperative oxygen-saturation nadir during sleep (less than 85%) (Fig. 31-9) was less than in those whose preoperative saturation nadir was greater.¹⁵⁹ Young age was also associated with an increased sensitivity to opioids. An unforeseen risk of perioperative opioid use in children with severe OSA is that smaller-than-expected doses of opioids may produce exaggerated respiratory depression. Of children with severe OSA who were anesthetized with halothane, 46% experienced apnea after a uniform dose of fentanyl, compared with 4% of controls.¹⁶¹ This increased sensitivity to the respiratory depressant effects of fentanyl in children with OSA is supported by the exaggerated respiratory depression to subsequent administration of a uniform dose of fentanyl in rat pups exposed to intermittent hypoxia.¹⁶² Hence, allowing spontaneous respirations during maintenance of anesthesia enables an assessment of the response to small challenges of opioid analgesics. In this manner, the anesthesiologist can assess the sensitivity of the child with OSA to opioids. Controlling respiration precludes such an evaluation. Sleep fragmentation blunts the arousal response to acute airway occlusion during sleep.^163,164 In addition, exposure to intermittent hypoxia during development is associated with an increase in the arousal latency to hypoxia.^165–167 Morphine acting at the level of the basal forebrain blunts arousal.¹⁶⁸ If the increased sensitivity to both the analgesic and respiratory effects of exogenously administered opioids reported in children with OSA extends to arousal mechanisms, the use of opioids in children with severe OSA may further impair arousal mechanisms. Guidelines for the perioperative management of OSA assign a greater risk score if opioids are used for postoperative analgesic regimens in children with OSA.⁹¹ Although these guidelines suggest that the use of low-potency oral opioid analgesia carries a reduced perioperative risk, the use of codeine, a “low-risk” oral opioid commonly used in the ambulatory setting, may also be problematic in children with OSA. Codeine is metabolized by the cytochrome P450 debrisoquine 4-hydroxylase (CYP2D6) to its active analgesic metabolites. The CYP2D6 gene displays polymorphism, including gene duplication (ultra-rapid metabolizers) and inactive genes. Gene duplication may lead to ultra-rapid metabolism, which for prodrugs, such as codeine, might yield a 50% greater fraction of morphine and its glucuronides compared with extensive metabolizers.¹⁶⁹ Respiratory arrest after codeine has been reported in both adults and children who demonstrate ultra-rapid metabolism of codeine.^170–171a Whereas the ultra-rapid metabolizing genotype is present in 3% of Caucasians, it is present in 10% to 30% of Arabian and Northeast African populations. In contrast, almost 10% of children lack CYP2D6, rendering codeine an ineffective analgesic. Given the broad variability in codeine metabolism and our lack of knowledge of which polymorphism is carried by each child, the use of codeine and the dose prescribed for children with OSA must be very carefully considered or an alternate opioid selected.

FIGURE 31-8 Relationship between morphine requirement, age, and the preoperative arterial oxygen-saturation nadir in 46 children who were otherwise well. The lengths of the stems supporting the 46 dots are proportional to the morphine dose. The stems in the foreground are shorter than those in the background, indicating a significant correlation between the three variables. Sao₂, Arterial oxygen saturation.

(From Brown KA, Laferrière A, Moss IR. Recurrent hypoxemia in young children with obstructive sleep apnea is associated with reduced opioid requirements for analgesia. Anesthesiology 2004;100:806-10.)

FIGURE 31-9 The total analgesic dose of morphine required to achieve a uniform analgesic endpoint in children with obstructive sleep apnea (OSA). Children were grouped by severity of OSA into those who had a preoperative oxygen saturation nadir of <85% or ≥85%. The asterisks indicate post hoc differences between groups, p < 0.05.

(From Brown KA, Laferrière A, Lakheeram I, Moss IR. Recurrent hypoxemia in children is associated with increased analgesic sensitivity to opiates. Anesthesiology 2006;105:665-9.)

Neural Blockade

Blockade of neural input to the upper airway dilator musculature in children with OSA is also problematic. Serious life-threatening complications, including severe UAO and pulmonary edema, have been reported after local anesthetics have been infiltrated in the tonsillar fossa to prevent pain after adenotonsillectomy. The pharynx in children with OSA is not only smaller in size,^147,172 but also more collapsible, even during wakefulness, compared with those children who do not have OSA.^173–175 Topical anesthesia applied to the mucosa of the pharynx of children with OSA reduces the caliber of the pharynx compared with control subjects.¹⁷⁶

Extubation Strategy and Management of the Postoperative Period in Children with OSA

Extubation of the trachea is usually performed when the child is fully awake. Techniques that involve minimal stimulation of the airway have been suggested.¹⁰¹ Although a minority of children receive muscle relaxants for adenotonsillectomy, residual neuromuscular blockade in the recovery room will selectively depress the function of the upper airway dilators relative to the diaphragm, promoting collapse of the pharyngeal airway.¹⁷⁷ Full antagonism of neuromuscular blockade is strongly recommended before extubating the tracheas of children with OSA.⁹¹ Antagonism of neuromuscular blockade with atropine and neostigmine after tonsillectomy has been associated with less PONV than antagonism with glycopyrrolate and neostigmine.¹⁷⁸

Several other factors may increase the risk of respiratory difficulties after adenotonsillectomy in children with OSA. Otherwise healthy children with severe OSA, whose adenotonsillectomy is performed in the morning, are less likely than those whose surgery is performed in the afternoon to desaturate when managed in a PACU setting.¹⁷⁹ In addition, meticulous attention to the position of the head and neck is required during recovery from anesthesia, because hypercarbia and a loss of lung volume (functional lung capacity) both promote collapse of the pharyngeal airway.^151,180,181 Extension of the cervical spine, the sniffing position, the lateral recovery position, and mouth opening with anterior advancement of the mandible all increase the dimension of the pharynx^182–186 and reduce the risk of UAO.

Two drugs, atropine and naloxone, have the potential to augment the function of the upper airway. Atropine administered after induction of anesthesia decreased the risk of postadenotonsillectomy respiratory complications.⁷⁰ Of possible relevance is the report that muscarinic blockade of the hypoglossal nucleus in the rat model enhances activity of the genioglossus muscle.¹⁸¹ Agonists of opioid µ-receptors have been shown to depresses activity in the pharyngeal dilator muscles, including the genioglossus muscle.^{155,187–189} Given the increased sensitivity to both analgesic and respiratory effects of exogenously administered opioids in children with severe OSA, a similar sensitivity may also apply to the respiratory-related activity of the pharyngeal musculature. Small doses of naloxone may alleviate UAO after adenotonsillectomy if exogenous opioids have been administered.

The severity of OSA is a predictor of the outcome after adenotonsillectomy.¹⁹⁰ A preoperative RDI above 19 may predict an RDI in excess of 5 in long-term follow-up.^75,93 Children with OSA continue to demonstrate obstructive apnea and desaturation during sleep on the first night after adenotonsillectomy, with the frequency of the obstructive events and the severity of desaturation usually greater in those children with severe OSA (Fig. 31-10).^191,192 Thus despite removal of the hypertrophied tonsils and adenoids, children with OSA continue to experience symptoms on the first postoperative night. This underscores the need to admit these children to a hospital for continuous overnight monitoring postoperatively, rather than discharge them home. Long-term follow-up studies more than 6 months after tonsillectomy in children with OSA show that symptoms completely resolve in those with mild OSA (AHI less than 10) but are persistent in 35% of those with severe OSA (AHI greater than 20).¹⁹⁰ Furthermore, recent epidemiologic evidence suggests that residual sleep-disordered breathing is more likely to be present after adenotonsillectomy in older children (more than 7 years of age) and obese children. It has also been suggested that obese children with large tonsils and OSA also show evidence of systemic inflammatory disease that persists after the tonsillectomy.^190,193

FIGURE 31-10 Three oximetry trend records from an otherwise healthy child. The x-axis is time ranging from bedtime on the left to arousal the following morning on the right. The top panel is the preoperative record showing clusters of desaturation. The middle panel is the record from the first night after adenotonsillectomy. With sleep onset, a decrease in saturation is evident that worsens after midnight. Oxygen therapy is administered after midnight. The bottom panel is the recording 6 weeks after adenotonsillectomy, which is within normal limits.

(From Nixon GM, Kermack AS, McGregor CD, et al. Sleep and breathing on the first night after adenotonsillectomy for obstructive sleep apnea. Pediatr Pulmonol 2005;39:332-8.)

Measures to support airway patency in the postoperative period have included insertion of nasal airways, administration of noninvasive ventilatory support (e.g., CPAP), reintubation, ventilation, and the administration of bronchodilators, racemic epinephrine, and heliox. Bilevel positive airway pressure and/or CPAP may be useful in children with preexisting neurologic disorders.¹⁹⁴ However, nasal secretions may be copious after adenotonsillectomy, limiting the efficacy of noninvasive ventilatory support. Children with complex medical diseases, who are critically dependent on the function of upper airway musculature, may benefit from delayed extubation. Acute relief of chronic UAO favors the exudation of intravascular fluid into the pulmonary interstitium and noncardiogenic pulmonary edema, which may present preoperatively, intraoperatively, and postoperatively. Supportive measures include the administration of oxygen, endotracheal intubation, mechanical ventilation with positive end-expiratory pressure, and administration of furosemide.^195–197

Discharge Policy for Ambulatory Adenotonsillectomy

Children younger than 3 years of age and those with complex medical disorders are not candidates for adenotonsillectomy as outpatients.^38,198 Although children undergoing adenotonsillectomy for obstructive breathing without apnea may undergo ambulatory surgery, those with OSA should not. A diagnosis of OSA increases the likelihood of respiratory complications after adenotonsillectomy from 1% in otherwise healthy children to 20% in those with OSA.³⁷

The majority of children who are scheduled for adenotonsillectomy have symptoms of obstructive breathing,^42,199,200 yet only 55% with clinical criteria suggestive of OSA subsequently meet sleep laboratory criteria for OSA.²⁰¹ Sleep screening of children undergoing routine adenotonsillectomy for chronic tonsillitis revealed unexpectedly that 20% had severe obstructive episodes associated with desaturation.²⁰² Because only a minority of children undergoing adenotonsillectomy undergo diagnostic testing for sleep-disordered breathing, the recently published guidelines on management of OSA have empowered clinical diagnostic criteria, such that a child with severe symptoms must be assumed to have moderate to severe OSA until proven otherwise by sleep laboratory testing (see Fig. 31-4). Ambulatory programs may now find it cost effective to screen children with a positive clinical history.

In otherwise healthy children, conversion from ambulatory to inpatient status was most frequently prompted by respiratory events in children whose indication for surgery was obstructive breathing.⁴² A systematic reduction in postoperative morphine use was associated with a reduced rate of hospital admission from 8% to 2.4%.⁵⁵ Same-day discharge, which abbreviates the postoperative stay in hospital and the minimum period of observation before discharge from hospital, has been the subject of much debate. Because the onset of respiratory complications in these children may be delayed,^69,179,191 a 6- to 8-hour period of observation for respiratory complications after adenotonsillectomy for OSA has been suggested. However, this extended period of observation does not preclude the delayed onset of sleep-related respiratory compromise after adenotonsillectomy. Table 31-5 presents common admission criteria for children undergoing elective tonsillectomy.

TABLE 31-5 Criteria for Overnight Admission after Tonsillectomy and Adenoidectomy

From Zalzal G: Personal communications, survey of major pediatric hospitals, 2006.

Post-Tonsillectomy Bleeding

Post-tonsillectomy bleeding is a surgical emergency. This can occur either within the first 24 hours (primary) or 5 to 10 days after surgery when the eschar covering the tonsillar bed retracts (secondary). Approximately 75% of postoperative tonsillar bleeding occurs within 6 hours of surgery. Sixty-seven percent of cases of postoperative bleeding originate in the tonsillar fossa, 27% in the nasopharynx, and 7% in both.²⁰³ Primary bleeding is typically more serious than secondary bleeding because it is usually more brisk and profuse. It is considered a surgical complication that is responsible for converting tonsillectomy from ambulatory surgery to a hospital admission in 1.6% of cases.⁴²

In a review of more than 9000 adenotonsillectomies in children performed with blunt and sharp (cold) dissection, the incidence of postoperative bleeding was 2.15%, with 76% of the hemorrhages occurring in the first 6 hours postoperatively.²⁰⁴ The authors of an audit of 4800 pediatric tonsillectomies for which hemostasis was secured with electrocautery (hot) techniques, reported a primary postoperative hemorrhage rate of 0.9%, with 83% presenting within 4 hours of surgery.⁵⁵ The consensus is that the period of observation for primary hemorrhage depends on the surgical technique: 6 hours and 4 hours, for cold and hot dissection, respectively,^55,203,204 although abbreviated periods of observation have been advocated by some.⁴²

The management of anesthesia in this situation can be challenging even in the hands of an experienced pediatric anesthesiologist.²⁰⁵ It often requires dealing with anxious parents, an upset surgeon, and a frightened anemic, hypovolemic child with a stomach full of blood. A thorough review of the anesthetic record of the original surgery will provide pertinent information about any existing medical condition, use of medications (such as aspirin), difficulty with airway management, and a rough estimate of intraoperative blood loss and fluid replacement, as well as the duration of known bleeding and the volume of blood vomited since the bleeding began. A quick history and examination of the child will provide vital information about the child’s current volume status. A history of dizziness and the presence of orthostatic hypotension may suggest a loss of more than 20% of the circulating blood volume and the need for aggressive fluid resuscitation and crossmatch of blood before induction.²⁰⁶ Even when severe hypotension is not present, the child with the bleeding tonsil is hypovolemic and has a decrease in cardiac output secondary to ongoing blood loss. If blood loss is severe, and/or fluid resuscitation is not vigorous, lactic acidosis and an eventual state of shock will develop. The compensatory response to acute blood loss is an outpouring of catecholamines. This causes peripheral vasoconstriction, which delays the clinical onset of hypotension in the awake child. When anesthesia-induced vasodilation occurs, profound hypotension may develop. Vigorous fluid resuscitation with crystalloids (repeated boluses of 20 mL/kg of balanced salt solution) and/or colloids is therefore the key to improve the cardiac output and achieve hemodynamic stability before induction of anesthesia. Hemoglobin or hematocrit determination should be interpreted in light of the child’s volume status and the type of fluid resuscitation administered. If the hemoglobin concentration is low, blood may be required; however, blood is rarely the primary solution for volume replacement in these children. If severe hypovolemia is suspected or if there may be a delay in obtaining blood, blood should be crossmatched for two or more units of packed red blood cells before the child reaches the OR. If a child bleeds after the tonsillectomy, and a bleeding blood vessel is not identified, it may be necessary to measure the prothrombin time, partial thromboplastin time, platelet count, and a bleeding time to rule out a bleeding diathesis. It cannot be overemphasized that the child must be adequately volume resuscitated before proceeding to the OR.

A child who presents with a bleeding tonsil has a full stomach (filled with swallowed blood) and may still be hypovolemic. A child who is spitting bright red blood may quickly exsanguinate, but the bleeding may be temporarily controlled by compression of the carotid artery ipsilateral to the bleeding source. The anesthesiologist may have difficulty visualizing the larynx because of the bleeding tonsillar bed and clots in the pharynx. A styletted ETT, two sets of well-illuminated laryngoscope blades and handles, and two large-bore Yankauer-type suction tubes must be available before induction of anesthesia (see also Chapter 4 and Fig. 38-5). On arrival in the OR and application of routine monitors, the child should be preoxygenated while positioned in the left lateral position and head down to drain blood out of the mouth (Fig. 31-11). The child is then turned supine, and a rapid-sequence induction is carried out with cricoid pressure (Sellick maneuver) applied by an assistant, to minimize the risk of aspirating blood into the lungs.²⁰⁷ There is no evidence that a rapid-sequence induction with cricoid pressure decreases the risk of aspiration in children with full stomachs, although this practice is commonplace. It should also be recognized that aspiration of blood into the lungs is not synonymous with acid particulate aspiration, unless the volume of blood aspirated compromises pulmonary oxygenation. The use of a full induction dose of propofol in a hypovolemic child could result in significant hypotension. A reduced dose of these induction agents (e.g., propofol, 1 to 2 mg/kg), or ketamine (1 to 2 mg/kg) or etomidate (0.2 mg/kg) for induction followed by atropine (0.02 mg/kg) combined with succinylcholine (1.5 to 2 mg/kg) or rocuronium (1.2 mg/kg) for tracheal intubation should facilitate a rapid control of the airway without hypotension. However, the systolic blood pressure after induction of anesthesia will provide a direction indication of the volume status of the child.

FIGURE 31-11 Preoxygenation with the patient in the lateral position to control post-tonsillectomy bleeding before induction of anesthesia.

When possible, a cuffed ETT (one-half size smaller than usual for age or weight) should be used to minimize the chance of aspirating blood. The use of a stylet is strongly recommended in spite of a previous history of easy intubation. Titration of an inhalational anesthetic, such as sevoflurane or desflurane with nitrous oxide and oxygen,⁹⁷ supplemented with an opioid, such as fentanyl, 1 to 2 µg/kg, will facilitate rapid recovery at the end of surgery.²⁰⁸ Often these surgeries are not excessively painful because surgery is limited to the area of bleeding. Controlling the bleeding vessel in the tonsillar bed can be accomplished rapidly if the blood pressure is maintained in the normal range. Hence, these surgeries are often quite brief and the anesthetic should be planned accordingly. Suctioning the stomach with a large-bore catheter under direct vision after the procedure does not guarantee an empty stomach, because much of the blood may be clotted and the clots are often too large to be suctioned. The use of prophylactic antiemetic therapy (e.g., ondansetron 0.1 mg/kg) is indicated.

The most important postoperative consideration is to extubate these children when they are fully awake and able to control their airway reflexes. Extubating the trachea while the child is in the lateral position may be the safest practice to minimize the risk of aspiration. If there is a medical indication to substitute high-dose rocuronium (1.2 mg/kg) for succinylcholine, then a prolonged period of relaxation may be anticipated. Sugammadex may allow early reversal of residual deep neuromuscular blockade with high-dose rocuronium, although at the time of this writing, sugammadex is neither approved for use in children nor available in the United States or Canada. Postoperatively, a repeat determination of the hemoglobin level may be indicated.

Peritonsillar Abscess

Peritonsillar abscess (quinsy tonsil) occurs in older children and young adults. It is the most common deep neck-space infection treated by otolaryngologists. Infection originates in the tonsil and spreads to the peritonsillar space between the tonsillar capsule and the superior constrictor muscle, and usually into the soft palate in the region of the superior pole of the tonsil. Commonly cultured organisms include aerobes, such as Streptococcus pyogenes, S. milleri, S. viridans, β-hemolytic streptococci, Haemophilus influenzae, as well as anaerobes, such as Fusobacterium and Prevotella species.²⁰⁹

Clinically, these children present with fever, pharyngeal swelling, sore throat, dysphagia, odynophagia, and often trismus. Trismus is caused by compression of nerves by the tense peritonsillar mass, spasm of the pterygoid muscles, and inflammation of the muscles of the face and neck. Dehydration can ensue because of fever and the persistent difficulty with swallowing.

Preoperative evaluation includes careful assessment of the airway, with special emphasis on the degree of trismus. Blood specimens should be analyzed for total and differential white blood cell count to ascertain the response to the infection, and for cultures for appropriate antibiotic therapy. Computed tomography of the tonsillar area will identify airway deviation or compromise and the extent of spread of the abscess (Fig. 31-12).

FIGURE 31-12 A, Peritonsillar abscess with trismus. B, Axial enhanced computed tomography scan through the oropharynx showing a 3-cm ring-shaped, enhancing, low-density mass (arrow) replacing the left tonsil, typical of a tonsillar abscess.

While awaiting the results of the cultures, treatment should begin with establishing IV access, hydration, and appropriate antibiotic coverage. The majority of organisms, including anaerobes, are penicillin sensitive. Consequently, penicillin is usually the antibiotic of choice.²⁰⁹ The three different procedures currently used to drain a peritonsillar abscess are needle aspiration, incision and drainage, and abscess tonsillectomy.²¹⁰ Most children undergo general anesthesia for treatment of peritonsillar abscess by incision and drainage, although in some centers, moderate to deep sedation has been successfully used.²¹¹ If the abscess is small and well confined, immediate tonsillectomy is performed.

The anesthetic management of these children can be challenging. Rupture of the abscess and possible aspiration of purulent material during laryngoscopy and intubation should be avoided during induction of anesthesia. Although the airway may appear to be compromised, most peritonsillar abscesses are in a fixed location in the lateral pharynx and do not interfere with mask ventilation. Visualization of the vocal cords is usually not impaired, because the pathology is supraglottic and well above the laryngeal inlet, although a right-sided abscess may interfere with the usual sweeping of the tongue to the left during laryngoscopy. Laryngoscopy must be carefully approached to avoid excessive manipulation of the larynx and surrounding structures. Occasionally, the pharyngeal swelling and the distortion of normal anatomy, along with excessive secretions, may create difficulty for laryngoscopy and intubation. The OR should be prepared as for any difficult airway case, with different sizes of ETTs, stylets, two sets of well-illuminated laryngoscopes, a Glidescope or other device to facilitate difficult intubation, and a tonsil-tip suction catheter attached to a powerful suction device. The surgeon must be present in the OR during induction of anesthesia, should airway obstruction occur. Equipment for cricothyrotomy or tracheotomy must be readily available.

These children are often older and do not require preoperative sedation. If trismus is present, an inhalational induction should be performed, using sevoflurane and oxygen while the anesthesiologist assesses mobility of the temporomandibular joint under anesthesia. An oropharyngeal airway is best avoided, lest the abscess is traumatized. Usually, awake trismus resolves once an adequate depth of anesthesia has been achieved. When this is confirmed, or if there was minimal trismus to begin with, then a short-acting muscle relaxant (or propofol) should be given to facilitate tracheal intubation. Alternatively, if there is minimal trismus and the preoperative airway assessment indicates minimal distortion, a rapid-sequence IV induction after adequate preoxygenation may be the best way to avoid trauma to the pharyngeal structures while struggling with a mask induction, needing to insert an oropharyngeal airway, and possibly rupturing the abscess.²

To avoid aspiration of purulent material during intubation and drainage, a cuffed ETT is recommended and the child is placed in Trendelenburg position. At the end of surgery, the child should be extubated awake, preferably in the lateral decubitus position.²

Diagnostic Laryngoscopy and Bronchoscopy

Although diagnostic laryngoscopy and bronchoscopy procedures are usually of brief duration, the anesthetic management can be challenging in small infants with an already compromised airway. Stridor, or noisy breathing due to obstructed airflow, is a common indication for a diagnostic laryngoscopy and bronchoscopy in infants and children. Inspiratory stridor results from UAO, expiratory stridor results from lower airway obstruction, and biphasic stridor is present with mid-tracheal lesions (see Chapters 11 and 12). Subglottic stenosis may follow prolonged tracheal intubation in an infant that was born preterm.

The evaluation of a child with stridor begins with taking a thorough history. The age at symptom onset helps suggest a cause; for instance, laryngotracheomalacia and vocal cord paralysis are usually present at or shortly after birth, whereas cysts or mass lesions develop later in life (Table 31-6). Information indicating positions that make the stridor better or worse should be obtained, because placing a child in a position that allows gravity to aid in reducing obstruction can be of benefit during induction.

TABLE 31-6 Causes of Stridor

Physical examination reveals the general condition of a child or infant, as well as the degree of the airway compromise. Laboratory examination may include a chest radiograph and barium swallow, which can aid in identifying lesions that may be compressing the trachea. Computed tomography, magnetic resonance imaging, and tomograms may be helpful in isolated instances but are not routinely indicated.

Laryngomalacia is the most common cause of stridor in infants and most often results from a long epiglottis that prolapses posteriorly and prominent arytenoid cartilages with redundant aryepiglottic folds that prolapse into the glottic opening during inspiration.²¹⁴ The definitive diagnosis is obtained by direct laryngoscopy and by rigid or flexible bronchoscopy.

Preliminary examination is usually carried out in the surgeon’s office. A small flexible fiberoptic bronchoscope is inserted through the nares into the oropharynx. Nasal insertion provides an excellent view of the movement of the vocal cords and pharyngeal structures. Topically treating the nasopharynx with lidocaine facilitates passage of the nasal pharyngoscope or bronchoscope. Alternatively, the examination can be accomplished in the OR in a lightly anesthetized child during spontaneous respirations. Children must be spontaneously breathing so that the vocal cords move freely. After movement of the vocal cords is observed and recorded, the anesthetic level can be increased as appropriate, a rigid bronchoscope (or just the telescope in small infants) is inserted through the vocal cords, and the subglottic area, the lower trachea, and bronchi are evaluated.

The use of premedication in these children should be individualized. Small infants may be brought into the OR unpremedicated; older children may experience respiratory depression and worsening of airway obstruction if heavily premedicated.

Usually an inhalational induction with sevoflurane is performed. Nitrous oxide can be used initially, if tolerated, to speed the induction and then discontinued before the examination. Because sevoflurane is relatively insoluble and is rapidly eliminated, ventilation will be intermittently interrupted during the examination, and the Hopkins optical telescope prevents adequate ventilation through the smallest diameter bronchoscopes, supplementation with IV agents, such as propofol (1 mg/kg boluses or a 50- to 100-µg/kg/min infusion), is necessary to maintain an appropriate depth of anesthesia. If an inhaled technique is used by insufflation, scavenging may be attempted by positioning a suction device near the child’s mouth.

A propofol-based total intravenous anesthesia (TIVA) technique has the advantage that it can be given continuously during the procedure, resulting in a more stable level of anesthesia than can be achieved with inhalational agents and intermittent ventilation. Propofol can be supplemented with small (0.5 mg/kg) doses of ketamine to enhance analgesia. Opioids can also be used but will frequently induce apnea.

The key to a stress-free bronchoscopy is properly placed topical anesthesia. Although topically treating the laryngeal structures with local anesthetic helps the child tolerate the procedure, it may interfere with assessment of normal vocal cord movement. For that reason, a local anesthetic is often topically applied after initial evaluation of the upper airway and just before insertion of the bronchoscope for evaluation of the distal airway structures.

After completion of pharyngoscopy and/or laryngoscopy, the surgeon generally proceeds to rigid bronchoscopy. The size of a rigid bronchoscope refers to the internal diameter (ID). Because the external diameter may be significantly greater than that of an ETT of similar size, care must be taken to select a bronchoscope of proper external diameter, to avoid damage to the laryngeal structures (Table 31-7). The rigid bronchoscope can be used for ventilation through the side port attached to the anesthesia circuit with a flexible extension. It is often most useful to paralyze the child with a fixed lesion, which diminishes the risk of vocal cord injury secondary to movement. For nonfixed lesions, such as an aspirated foreign body, and for assessment for bronchomalacia or tracheomalacia, it is preferable to proceed with spontaneous ventilation, a deep level of anesthesia, and good topical anesthesia of the vocal cords and carina. Adequate oxygenation should be maintained in these infants throughout the procedure. Because ventilation may be intermittent and at times suboptimal, it is recommended that 100% oxygen be used as the carrier gas during the bronchoscopic examination. During ventilation of the infant with the optical telescope in place, high resistance may be encountered as a result of partial occlusion of the lumen. This is especially likely when the 2.5-, 3.0-, and 3.5-mm ID scopes are used. Large fresh-gas flow rates, large tidal volumes with high inflation pressures, and large concentrations of inspired inhalational anesthetic (or TIVA) are often necessary to compensate for leaks around the ventilating bronchoscope and the high resistance encountered when the optical telescope is in place. Hand ventilation at greater than normal rates is most effective in achieving adequate ventilation. Sufficient time for exhalation must be provided for passive recoil of the chest. In small infants, there may be room for only the optical telescopic light source, which does not have a ventilation channel. In these cases, insufflation of oxygen via a small tube placed in the hypopharynx via the nose or mouth will delay the onset of desaturation in a spontaneously breathing child. If (when) desaturation occurs, the surgeon must stop and allow the child to be oxygenated before continuing with the examination.

TABLE 31-7 External Diameter of Standard Endotracheal Tube versus Rigid Bronchoscope

^*Mallinckrodt Medical, Inc., St Louis.

^†Karl Storz Endoscopy-America, Inc., El Segundo, Calif.

At the conclusion of bronchoscopy, the surgeon may wish to determine the size of the larynx and determine the degree of airway narrowing. An uncuffed ETT is inserted beyond the narrowest portion of the obstructed airway, and the airway is assessed by applying positive pressure between 10 and 25 cm H₂O to the airway and listening with a stethoscope for an air leak around the ETT at the level of the suprasternal notch. The outer diameter of the appropriate ETT is compared with the inner diameter of the child’s larynx and trachea, and the percentage of obstruction is calculated. Grade I obstruction involves up to 50% of the airway, grade II is from 51% to 70%, and grade III is greater than 70% (Fig. 31-13, B).²¹⁵

FIGURE 31-13 A, Method for estimating the percentage of airway obstruction. After easy passage of an uncuffed endotracheal tube (ETT ), a manometer is placed at the connection of the elbow of the anesthesia circuit and the ETT. A stethoscope is placed over the larynx and the circuit is slowly pressurized. The pressure at which a leak is auscultated (10 to 25 cm H₂O) is matched with the age of the child and the size of the ETT to estimate the percent of laryngeal narrowing shown in numbers in teal boxes. Clear boxes indicate the usual size ETT for child’s age. Grade I, light teal, Grade II, medium teal, and Grade III, dark teal. B, Schematic representation of subglottic stenosis classification system. This chart is based on one institution’s experience, and the manufacturer of the ETTs was not described, thus the actual external diameter of the ETTs used is unknown. ID, Internal diameter.

(Reproduced and modified with permission from Myer CM III, O’Connor DM, Cotton RT. Proposed grading system for subglottic stenosis based on endotracheal tube sizes. Ann Otol Laryngol 1994;103:319-23.)

An alternative method of ventilation during bronchoscopy is the Sanders jet ventilation technique. The principle of jet ventilation involves intermittent bursts of oxygen delivered at a maximum pressure of 50 psi from a hand-regulated pressure-reducing valve to the lungs, through a 16-gauge catheter attached to a rigid bronchoscope.²¹⁶ Current jet ventilators include adjustable pressure-control valves that permit attenuation of the peak pressure, a desirable feature if this device is to be used in a child. Intermittent flow is accomplished by depressing the lever of an on-off valve. A jet of oxygen is released at the tip of the 16-gauge catheter, creating a Venturi effect that entrains room air into the bronchoscope. This jet of oxygen and room air mixture allows inflation of the lungs to occur. Exhalation is passive and depends on the recoil of the chest wall. Although this technique is usually effective for both oxygenation and ventilation in experienced hands, a number of potential problems exist. Because of potentially high inflation pressure, pneumothorax, pneumomediastinum, and death can occur.²¹⁷ Blood or infectious or particulate matter in the airway may be forced distally by high-pressure bursts. There is also the possibility of hypoxemia in some children, because the high-pressure oxygen entrains room air, diluting the oxygen.

High-frequency jet ventilation is also possible for upper airway endoscopy and laryngotracheal surgery. Obstruction to expiratory flow is a major concern and is dependent on good positioning of the rigid laryngoscope. Complications, such as barotrauma, pneumopericardium, CO₂ retention, necrotizing tracheobronchitis, and gastric rupture, dictate a fastidious technique.²¹⁸

Dexamethasone in a dose of 0.5 mg/kg IV (maximum dose, 10 to 20 mg) is frequently administered during the procedure to decrease postoperative laryngeal swelling and the possibility of croup. At the conclusion of rigid bronchoscopy, an ETT can be placed in the trachea to control the airway during recovery from anesthesia or, if ventilation is adequate and the anesthetic depth is not excessive, the child can be allowed to emerge breathing 100% oxygen by a facemask.

Laryngotracheobronchitis (CROUP)

Croup is a symptom complex of inspiratory stridor; suprasternal, intercostal, and substernal retractions; barking cough; and hoarseness that results from swelling of the mucosa in the subglottic area of the larynx.² There are two common entities that account for most cases of croup: spasmodic croup, and laryngotracheobronchitis. Spasmodic croup has been diagnosed in about 3% of children with stridor.²¹⁹ The child is otherwise healthy and afebrile, presenting with nocturnal episodes of spasmodic cough, which is described as barking and high pitched. The disease is self-limiting. Besides viruses, allergic and psychological factors are blamed for this acute phenomenon. It differs from acute laryngotracheitis in that it is considered an allergic reaction to viral antigens rather than a true infection with the viruses.²²⁰ Besides lack of fever, spasmodic croup is usually remarkable for lack of severe laryngeal inflammation, and, in general, supportive therapy on an outpatient basis is all that is required.

Viral laryngotracheitis is by far the most common form of infectious croup. The disease has a gradual onset, usually after a URI in a young child. Low-grade fever is common. Children who have more than two episodes of croup requiring hospitalization should be evaluated for subglottic narrowing from stenosis or cysts. Clinical scoring systems based on objective criteria are helpful in following the progress of the disease and in judging the effectiveness of therapy (Table 31-8).²²¹

Anteroposterior radiographs of the neck will confirm the diagnosis and rule out acute epiglottitis or the possibility of a foreign body in the airway (Table 31-9).²²² The viral infection affects the subglottic region of the larynx, causing edema. The characteristic radiograph of croup, therefore, includes blurring of the tracheal air shadow on lateral neck films, and symmetrical narrowing of the subglottic air shadow, described as “church steeple” or “sharpened pencil” sign on anteroposterior films (Fig. 31-14 and E-Fig 31-3). The lateral neck radiographs show normal supraglottic structures and normal epiglottic shadow.

TABLE 31-9 Differential Diagnosis of Croup and Epiglottitis

^*Foreign bodies in the airway should also be considered.

From Hannallah R. Epiglottitis. In: Stehling L, editor. Common problems in pediatric anesthesia. 2nd ed. St Louis: Mosby-Year Book; 1992, p. 277-81.

FIGURE 31-14 A, Radiograph of the normal upper airway (anteroposterior view). Note that the subglottic area is rounded. B, Laryngotracheobronchitis (croup) produces swelling (edema and inflammation), which obliterates the normal rounded subglottic area, producing the so-called sharpened pencil or steeple sign. C, Schematic representation showing progressive swelling of the subglottic area. For an additional view, see E-Figure 31-3.

E-FIGURE 31-3 Additional view of normal upper airway (left) and a child with laryngotracheobronchitis and the “steeple” or “sharpened pencil” sign (right) (see Fig. 31-14).

The majority of cases will resolve quickly with simple conservative measures, such as breathing humidified air or oxygen. Less than 10% of cases require hospitalization because of significant respiratory difficulty, and fewer still require an artificial airway.²¹⁴ Humidification of inspired gases is usually effective in improving respiratory distress, and it prevents drying of secretions, although despite the popularity of cool mist therapy, it is not evidence-based practice.²²³ Oxygen is obviously essential to prevent or to treat hypoxemia, which may result from ventilation-perfusion mismatching caused by accumulation of secretions. Hydration prevents thickening of tracheal secretions.

Racemic epinephrine is the most effective drug therapy for these children, although l-epinephrine has also been effective. Racemic epinephrine is available as a 2.25% solution, which is diluted in water or saline, and administered either by intermittent positive-pressure ventilation via a face-mask or nebulization.²²⁴ Nebulized racemic epinephrine is administered in cases of mild-to-moderate obstruction. The solution is prepared by diluting a volume of 2.25% racemic epinephrine in 2 mL of saline or sterile water according to the child’s weight in kilograms (i.e., 0.25 mL of racemic epinephrine for 0 to 20 kg, 0.5 mL for 20 to 40 kg and 0.75 mL for greater than 40 kg).²²⁵ Because the duration of action of racemic epinephrine is brief, rebound edema may occur. Treatments are required every 1 to 2 hours, and the child should be observed for at least 2 hours after treatment. For l-epinephrine, the volume of a 1% solution is the same as that for racemic epinephrine.

If treatment with racemic epinephrine is unsuccessful, in addition to edema, the underlying problem may be obstruction caused by thick, inspissated secretions possibly related to bacterial superinfection, such as bacterial tracheitis.^226,227 In this situation, or if the child appears exhausted from the increased work of breathing, relief of the obstruction must be obtained through endotracheal intubation, followed by pulmonary suctioning. The clinical assessment of “exhaustion” in children with croup may be difficult. An alternative approach is to consider intubating the tracheas of those children who have arterial oxygen saturation less than 90% when breathing air, despite nebulized epinephrine and steroid treatment. Laryngotracheobronchitis is also a disease of the lower airways. An inability to clear secretions contributes to atelectasis and arterial oxygen desaturation. Intubation is often required to allow suctioning of the copious yellow secretions.

One large series (512 consecutive admissions in a single year) reported that approximately 6% of children who had sternal and chest retractions on admission and failed to respond to conventional medical therapy required endotracheal intubation.²²⁸ Intubation should be performed in the OR under controlled anesthetic conditions, as for a child with severe epiglottitis. The tracheal tube selected should be at least one-half size smaller (0.5 mm ID) than would normally be chosen, to avoid aggravating the subglottic edema and possibly causing subglottic stenosis.^229–231 Children whose airways have been intubated are admitted to the ICU, and special care is provided for suctioning of inspissated secretions. The tracheal tube usually remains in place for 3 to 5 days.

Corticosteroid therapy for laryngotracheobronchitis has become the standard of care.²³² Single-dose corticosteroid therapy appears safe and effective,²³³ although large studies of the risk of progression of viral infection or the development of secondary bacterial infections in moderate to severe laryngotracheobronchitis are lacking; reports suggest that IV dexamethasone (0.5 to 1 mg/kg) may be effective.²³⁴ There is evidence that there is rapid clinical improvement 12 and 24 hours after steroid treatment, which significantly reduces the incidence of endotracheal intubation.^235–237 Antibiotics are generally not indicated in the treatment of uncomplicated viral croup.

The child is usually ready for extubation within 2 to 4 days. Criteria to consider include abatement of fever, diminished tracheal secretions, change in the character of secretions to a thin and watery type, and an audible air leak that develops around the nasotracheal tube as the edema subsides.

Acute Epiglottitis

Although rarely seen today, acute epiglottitis can be fatal because it can produce seemingly unprovoked sudden and complete airway obstruction. It is a clinical and pathologic entity that should more correctly be termed supraglottitis, because the arytenoids and aryepiglottic folds, as well as the epiglottis itself, are usually affected. All supraglottic structures become swollen and stiffened by inflammatory edema. Although the main focus of infection is the oropharynx, the disease produces a generalized toxemia. Epiglottitis is most common between the ages of 3 and 5 years, but it can occur in any age; historically, the causative organism was typically Haemophilus influenzae type B.^2,238–240 However, with the widespread use of H. influenzae vaccination, the incidence of epiglottitis in children has all but disappeared in medically advantaged countries.^241,242 Streptococcus,²⁴³ Staphylococcus,²⁴⁴ Candida,²⁴⁵ and other fungal pathogens²⁴⁶ have become more frequent causes of this now rare disorder in children, although the incidence in adults has not diminished substantially.²⁴⁷ It should be noted that vaccine failures may occur or parents may refuse proper immunizations of their child, resulting in susceptibility to H. influenzae type B infection.^248,249 Epiglottitis has become more of a disease of adults.²⁵⁰

The onset is usually abrupt, with a brief history of high fever, severe sore throat, and difficulty in swallowing. Stridor, if present, is usually inspiratory, and because the subglottic structures are usually unaffected, there is little or no hoarseness. An expiratory snore, rather than inspiratory stridor can often be heard. The child appears toxic, and, in an attempt to improve airflow past the swollen epiglottis, assumes the sitting position, leaning forward in the sniffing position (E-Fig. 31-4). The mouth is open, with the tongue protruding. The child frequently drools because of difficulty and pain on swallowing. The mnemonic SNORED is often useful for diagnosis: Septic, NO cough, Rapid onset, Expiratory snore, Drool.

E-FIGURE 31-4 Clinical appearance of a child with epiglottitis; this child is sitting upright, leaning forward, and drooling.

In addition to high fever, other signs of generalized toxemia may include tachycardia, a flushed face, and prostration. The respiratory pattern is usually slow and quiet to allow more comfortable breathing.

Acute epiglottitis is a clinical diagnosis. It must remain prominent in the differential diagnosis of a child presenting with signs and symptoms of UAO. However, in some early cases, the clinical presentation alone may be inconclusive. If so, a lateral radiograph of the neck will usually demonstrate a swollen epiglottis and aryepiglottic folds (Fig. 31-15 and E-Fig 31-5). The vallecula may be obliterated, but subglottic structures are usually clear. A physician capable of establishing an airway should always be in the child’s attendance (especially if in a remote area of the hospital, such as Radiology), because total airway obstruction can develop during the radiologic examination, especially if the child is forced to lie supine. This is one reason why the use of lateral neck radiographs in the differential diagnosis of UAO is avoided. Examination of the pharynx and larynx should only be attempted in an area with adequate equipment and staff prepared to intervene should UAO develop; ideally, the OR. The safest, most conservative approach to the management of acute epiglottitis is to establish an artificial airway as soon as the diagnosis is made, and then, with the airway secured, to proceed with appropriate antibiotic and supportive therapy. The child should remain in the sitting position at all times and never forced into the supine position. No attempts to examine the larynx should be made in the emergency room.²

FIGURE 31-15 A, Lateral neck radiograph of child with epiglottitis. Note the marked thickening of the aryepiglottic folds (arrow). B, Schematic representation of A. Note the marked thickening of the aryepiglottic folds (A), loss (“amputation”) of the vallecula (curved arrow), swelling of the epiglottis (E ), and distention of the hypopharynx (H). C, Schematic representation of epiglottitis demonstrating progressive swelling of the lingual surface of the epiglottis, resulting in “amputation” of the vallecula. Progressive swelling leads to trapdoor-like occlusion of the glottic opening (curved arrow). For additional views, see E-Figure 31-5.

E-FIGURE 31-5 Additional view of child with epiglottitis. Arrow points to the swollen epiglottis, known as the “thumb sign” (see Fig. 31-15).

These children should not be premedicated. Instead they should be brought to the OR calm and undisturbed. If it takes the presence of a parent to achieve this, then that is what should be done. In the OR, with equipment and personnel who can insert a surgical airway immediately present, a precordial stethoscope, pulse oximeter, and other standard monitors are applied. General anesthesia is induced with oxygen and sevoflurane with the child still sitting up. Spontaneous respiration is continued as the child is gently allowed to recline. If the child is moribund, then an awake intubation should be considered.

When a surgical stage of anesthesia is achieved, IV access is established and secured. A large fluid bolus of balanced salt solution is infused (20 to 30 mL/kg) because these children are often dehydrated and will require a deep plane of anesthesia to permit tracheal intubation while spontaneous respirations are preserved. Some anesthesiologists would also administer an antisialagogue to reduce secretions. Epiglottitis is marked by progressive swelling of the lingual surface of the epiglottis with resultant obliteration of the vallecula (see Fig. 31-15). Viewing the glottic opening without traumatizing the epiglottis may usually be accomplished by forcing the tip of the laryngoscope blade along the center of the base of the tongue into the vallecula, where the vallecula has been obliterated by the swollen lingual surface of the epiglottis (see Fig. 31-15, C). Lifting the base of the tongue, without directly touching the epiglottis, can then expose the glottis. A stylet within the ETT may be helpful because it provides increased rigidity to facilitate introduction through a partially obstructed glottic aperture. The size of the ETT should be one-half size smaller (0.5 mm ID) than otherwise selected for the same age child. By choosing an ETT with a smaller ID than usual, one also lessens the risks of pressure necrosis on the mucosa. Figure 31-16 illustrates a case of severe epiglottitis (before [A] and after [B] the airway was secured). A styletted orotracheal tube is inserted first, and may be replaced by a nasotracheal tube of appropriate size. However, if the glottic opening was difficult to visualize, then no attempt should be made to replace the oral tube with a nasal one. The orotracheal tube may displace supraglottic edema, improving the view of the glottic opening and facilitating placement of the nasotracheal tube. An air leak at 20 to 25 cm of H₂O, when present, confirms the selection of an appropriate size tube. Because the airway obstruction in epiglottitis is supraglottic, not subglottic, the nasotracheal tube size is often the usual size or one-half size smaller for the child’s age. A larger tube is not necessary and may contribute to the possible development of serious laryngeal complications, such as subglottic stenosis. The child should be able to breathe around the tube, as well as through it. If the anesthesiologist is unable to intubate the trachea, then a rigid bronchoscope should be used. If both of those maneuvers fail, then a tracheostomy or cricothyrotomy should be performed (see Fig. 12-25).^251,252

FIGURE 31-16 Acute epiglottitis. A, The entire upper airway is inflamed and there is marked swelling of the epiglottis. B, Photograph taken after securing the airway with an endotracheal tube.

Once the airway is secured, a culture of the pharynx and blood cultures are obtained, and aggressive medical therapy beginning with antibiotics should be commenced. It is recommended that cephalosporins (such as ceftriaxone 50 mg/kg/day)^253–255 be used initially for antibiotic therapy, with the first dose immediately after the diagnosis is made and appropriate cultures taken.² The duration of the treatment is controversial, but at least 3 to 5 days of IV antibiotics followed by oral therapy is usually the minimum. Steroids are not indicated. Supportive measures include IV hydration, airway care, sedation as necessary, and acetaminophen for fever. Negative-pressure pulmonary edema can develop after tracheal intubation in children with severe epiglottitis.¹⁹⁵ When the child resumes swallowing and the fever abates, usually 24 to 48 hours after initiation of therapy, the acute supraglottic edema should be resolving and the child may be prepared for tracheal extubation.

Obstructive Laryngeal Papillomatosis

Recurrent respiratory papillomatosis, also known as juvenile laryngeal papillomatosis, is the most commonly found tumor in the larynx and upper airway in children. Recurrent respiratory papillomatosis is caused by the human papilloma virus (HPV). The incidence is only 1 in 400 births, even though active or latent viral infection is present in 10% to 25% of pregnant women.²⁵⁶ This disease is caused by HPV 6 and 11; the incidence may markedly decrease in the future, with the introduction of a maternal vaccine to prevent HPV infection for types 6, 11, 16, and 18.^257–260 The papillomas are usually found in the larynx on the vocal cord margins, epiglottis, pharynx, or trachea (Fig. 31-17). If left untreated, symptoms of aphonia, respiratory distress, hoarseness, stridor, right ventricular hypertrophy, and cor pulmonale may occur.

FIGURE 31-17 Large pedunculated papillomas obstructing the laryngeal inlet.

The current treatment is primarily surgical removal of the papillomatous tissue using the CO₂ laser under microscopic visualization. Alternatively, papillomas can be surgically debulked using an ultrasonic microdebrider or cup forceps before laser treatment. Topical application of mitomycin C (usually in combination with debulking procedures) has also been shown to be effective in suppressing these tumors. Nonsurgical treatment using interferon alfa-n1 has been beneficial in some children.²⁶¹ The main goal of the treatments is to reduce the bulk of the lesion without scarring and permanent damage to the underlying mucosa.

Because of the recurrent nature of this condition, most children will return frequently for treatment. Many may require monthly scheduled visits to the OR to prevent recurring obstruction. If some of these scheduled sessions are missed, or if the progress of the disease is accelerated, the child will present with an acute exacerbation of obstructive symptoms requiring emergent endoscopic resection. In all cases, it is important to obtain a careful history, including inquiry about changes in voice or increased difficulty breathing during daily activities, that may indicate progressive airway obstruction.

Because of frequent hospitalizations, these children become psychologically sensitized to the perioperative experience. Premedication is usually avoided if the degree of airway obstruction is significant and there are concerns about compromising spontaneous ventilation. In selected cases, when the children are extremely anxious and/or upset, the parents (or a child-life surrogate) may accompany the child to the OR for induction, to provide emotional support.

The perioperative care can be very challenging and often depends on the degree of obstruction to airflow and the type and location of the papillomas.²⁶² Pedunculated papillomas can produce complete ball-valve obstruction of the upper airway in certain positions. It is therefore prudent to avoid paralysis and to maintain spontaneous respirations until the airway is examined and the anesthesiologist is certain that assisted or controlled ventilation is possible. These children must be approached and monitored in the same manner as any child with anticipated severe airway obstruction (e.g., acute epiglottitis). The surgeon must be present in the OR when anesthesia is induced, with equipment immediately available to deal with complete airway obstruction, including rigid bronchoscopes and a tracheostomy–cricothyrotomy set. The problem of sharing the already compromised airway with the surgeon is worsened by the need to use a laser to excise these lesions. A laser (an acronym for light amplified by stimulated emission of radiation) consists of a tube with reflective mirrors at either end with an amplifying medium between them to generate electron activity in the form of light. The CO₂ laser is the most widely used in medical practice, having particular application in the treatment of laryngeal or vocal cord papillomas, laryngeal webs, and resection of subglottic tissue and hemangiomas. A laser is useful for endoscopic procedures because the beam may be directed down open-tube endoscopes and is invisible, thereby affording the surgeon an unobstructed view of the lesion during resection. Laser energy is absorbed by tissue water, rapidly increasing its temperature, denaturing protein, and causing vaporization of the target tissue. The thermal energy produced by the laser beam cauterizes capillaries as it vaporizes tissues; therefore, bleeding is minimal and very little postoperative edema occurs.

These properties give the laser a high degree of specificity; however, they also provide the route by which a misdirected laser beam may cause injury to a child or to unprotected OR personnel.²⁶³ Laser radiation increases the temperature of absorbent material; therefore, flammable objects, such as surgical drapes, must be kept away from the path of the laser beam. Unprotected surfaces, such as skin, can be burned and must be shielded. Wet towels should be applied to cover the skin of the face and neck when the laser is being used to avoid burns from deflected beams.

The anesthetic management of these children depends on the approach the surgeon will use to remove the lesions. The basic choice is between intubation and nonintubation techniques. For the latter approach, the choice is between intermittent apnea versus jet ventilation.²¹⁷ The ETT used during laser surgery can affect the safety of the technique. All standard polyvinylchloride ETTs are flammable and can be ignited and vaporized by a laser beam. Although red rubber ETTs do not vaporize, they deflect the laser beam when wrapped with metallic tape. The metallic tape can only be applied along the stem of the tube down to the cuff. As a result, the laser may damage the tube below the vocal cords. Alternatively, nonlatex ETTs are manufactured specifically for use during laser surgery. Some have a double cuff to protect the airway in the event the outer cuff is damaged by the laser beam. Others have a special matte finish that is effective in deflecting the laser beam along its entire length. Nonreflective flexible metal ETTs and specifically wrapped ETTs are also specifically manufactured for use during laser surgery (Fig. 31-18). The outer diameters of these special tubes are considerably larger than the polyvinylchloride counterpart, especially in the small sizes. Thus they may not be appropriate for use in very small infants or children with a severely narrowed airway. Table 31-10 presents a variety of such specialized tubes compared with standard ETTs. Although these ETTs offer some advantage, they are considerably more expensive than metallic-tape–wrapped red rubber ETTs. A syringe or a bag (500 or 1000 mL) of normal saline should be immediately available to douse ignited tissues in the event of an airway fire.

FIGURE 31-18 Cuffed and uncuffed red rubber endotracheal tubes may be wrapped with reflective metallic tape for use during laser airway surgery. Note that this metallic tape is not approved by the Food and Drug Administration for this application. A, Cuffed and uncuffed commercially available foil-wrapped laser tubes are available (Laser-Shield II, Medtronic Xomed, Jacksonville, Fla.). B, An example of several commercially available stainless steel laser endotracheal tubes (V. Mueller Stainless Co., Chicago). Note that the external diameters of these devices are greater than those of standard endotracheal tubes.

Once the airway is secured, one anesthetic approach is to use intermittent apnea with paralysis, TIVA, and topical lidocaine. An antisialagogue, such as glycopyrrolate, is often given at the beginning of the anesthesia, together with dexamethasone (0.5 mg/kg [maximum dose 10 to 20 mg]) to reduce mucosal swelling resulting from repeated intubations; this dose of dexamethasone however is empiric and not evidence based. Anesthesia is typically induced with oxygen and sevoflurane while the anesthesiologist gradually assists respiration as the depth of anesthesia increases. Once IV access is established, the anesthesia is deepened further and the larynx is anesthetized with topical lidocaine (3 to 4 mg/kg). The airway is then evaluated and tracheal intubation is performed. The ETT chosen is usually several sizes smaller than what is normally appropriate for the child’s age, because most of these children have some degree of laryngeal scarring from repeated resections, and there is the need to prevent the ETT from obscuring the surgeon’s view and interfering with access to the lesions.

Although the goal is to achieve the desired depth of anesthesia to secure the airway with the child still spontaneously breathing, partial obstruction is frequently encountered before an adequate depth of anesthesia for laryngoscopy is achieved. In these cases, thrusting the jaw forward and applying positive pressure in the anesthetic circuit will maintain an open airway in most situations (see Chapter 4). If complete obstruction is encountered, then a single IV bolus of propofol (2 to 3 mg/kg) or a short-acting muscle relaxant may be necessary for immediate laryngoscopy and intubation, or to allow the surgeon to perform rigid bronchoscopy.

Once the correct position of the ETT is confirmed, a neuromuscular blocking agent (e.g., rocuronium) can be administered and the TIVA technique with propofol (200 to 300 µg/kg/min) and fentanyl (2 to 3 µg/kg) or remifentanil infusion (0.1 to 0.25 µg/kg/min or more, as needed) is started. Muscle relaxation is desirable to produce an immobile surgical field. A neuromuscular blockade monitor should be used to assess the degree of relaxation.

An apneic anesthetic technique without an ETT offers the best unobstructed view of the larynx and avoids the presence of flammable material (e.g., the ETT) in the path of the laser beam. The child is positioned for suspension laryngoscopy with eyes protected with moist eye pads, and the otomicroscope and CO₂ laser equipment are aligned. The ETT is then removed and surgical resection is carried out during repeated periods of apnea. The need for reintubation is guided by the adequacy of oxygenation as reflected by the pulse oximeter. Reintubation can be readily performed by the surgeon by introducing the tracheal tube through the suspension laryngoscope under direct vision. After each reintubation, the lungs are ventilated manually to restore both the oxygen saturation and end-tidal CO₂ to baseline. When those baselines are reached and surgery can resume, the trachea is extubated. This process is repeated until the surgery is complete.²

A modification of the apneic technique that avoids tracheal intubation is the jet ventilator. The operating laryngoscope may be fitted with a catheter through which O₂ flows, entraining ambient air. In this manner, the lungs are intermittently inflated by the pressure delivered by the jet. The advantage of this technique is twofold. The surgical field is extremely quiet because large excursions of the diaphragm are eliminated and ventilation is uninterrupted. However, transtracheal jet ventilation carries a greater risk of pneumothorax in children than the transglottic approach.²¹⁷ In the past, tension pneumothorax and pneumomediastinum occurred because of excessive peak inspiratory pressures during jetting. Maximum peak inspiratory jet pressures of approximately 15 mm Hg have reduced this risk dramatically. In morbidly obese children and those with severe disease of the small airways, effective ventilation may be difficult with this technique, and an alternate approach should be used.²⁶⁴ In addition, jet ventilation may theoretically distribute papilloma virus throughout the tracheobronchial tree, although this technique continues to be used.

When surgery is completed, the ETT is reinserted and secured until the child is completely awakened. Postoperative measures to prevent laryngeal edema, such as racemic epinephrine inhalation and/or the use of dexamethasone, are usually indicated.

Aspirated Foreign Bodies

Curious young children can push many loose objects into almost any orifice in their body. Objects inserted in the nose or ear are usually benign in nature and simple to remove once the child is anesthetized. Small button-sized battery foreign bodies require urgent removal because of their potential for extensive local damage.²⁶⁵ Impacted, or displaced objects present greater challenges for the anesthesiologist and endoscopist, and the danger of misplacement into the respiratory tract must always be considered.²⁶⁶

Tracheobronchial foreign-body aspiration is most common in toddlers 1 to 3 years of age. The majority (95%) of foreign bodies lodge in the right main-stem bronchus.²⁶⁷ A history of choking while eating or playing, persistent cough, or wheezing that does not respond to medical treatment may be the only manifestations. If the foreign body completely obstructs a bronchus, or creates a ball-valve phenomenon, distal hyperinflation from air trapping may occur; a hyperinflated lung during the expiratory phase may be the only indication of an aspirated foreign body on chest radiography (Fig. 31-19). The more distal the object is lodged in the airway, the more atelectatic changes are noted.

FIGURE 31-19 A, Expiratory radiograph of the chest demonstrates marked right-sided hyperinflation because of air trapping by the ball-valve effect of the foreign body. Chest radiograph may appear normal during inspiration after foreign body aspiration. A hyperinflated right lung (B) and a leftward mediastinal shift during expiration (C) suggest a foreign body in the right main-stem bronchus.

(Radiographs courtesy Sjirk J. Westra, MD, Division of Pediatric Radiology, Massachusetts General Hospital.)

Foreign bodies lodge in the trachea (less than 5% of airway foreign bodies) if they are too large to pass the carina.²⁶⁸ The signs of a tracheal foreign body may include a brassy cough with or without abnormal voice, bidirectional stridor, or complete airway obstruction in the case of laryngeal foreign bodies. Any sharp object, or any object that causes acute UAO with cyanosis and an inability to maintain ventilation, requires emergent removal. Unroasted peanuts (with unsaturated double bonds in the oils) should be removed promptly, because the oil can cause an inflammatory response and subsequent pneumonitis (Fig. 31-20).²⁶⁹ In contrast, roasted peanuts (with saturated double bonds in the oils) may be present in the lungs for greater periods without inducing as severe an inflammatory response. In addition, peanuts tend to swell, fragment, and crumble over time, making removal “en bloc” extremely difficult. The child who presents with a history of cyanosis after aspiration of a nut, very likely has aspirated material into the trachea or into the lungs bilaterally (as in the case of a broken nut or multiple nuts) and should be assessed emergently. It should be noted that esophageal foreign bodies may compress the trachea as well (Fig. 31-21).

FIGURE 31-20 A classic peanut in the bronchus. Note the irritation caused by the oil of the peanut.

FIGURE 31-21 Anteroposterior (A) and lateral (B) neck radiographs of a child who swallowed two coins. Note tracheal compression caused by these foreign bodies in the esophagus (arrow).

The anesthetic management of these children depends on the level, degree, and duration of obstruction. A child who aspirates a foreign body while eating, or soon thereafter, presents with the additional risk of a full stomach. Waiting for the stomach to empty may not be appropriate or even effective in the acute situation. IV metoclopramide (0.15 mg/kg) may be used to hasten stomach emptying but does not guarantee that the stomach empties.²⁷⁰ If time permits, the administration of an anticholinergic agent may be useful to reduce secretions. In the debate of how best to anesthetize a child with a full stomach and a compromised airway from an aspirated foreign body, concern for the airway takes precedence over the full stomach and an inhalational induction is recommended.

One of the major controversies in the anesthetic management of foreign body aspiration is whether to control ventilation or allow spontaneous respirations during bronchoscopy. Some endoscopists prefer a spontaneously breathing child, to prevent movement of the foreign body as it is being retrieved out of the airway. Sevoflurane is the preferred inhalational anesthetic in these children because it maintains spontaneous respirations, does not trigger upper airway reflex responses, and maintains hemodynamic stability.²⁷¹ Anesthesia is usually maintained with 100% oxygen and sevoflurane, or a propofol-based TIVA technique.² Halothane has some advantages over sevoflurane during maintenance because it is more soluble and more slowly eliminated, which allows more time to manipulate the airway without the child recovering from the anesthetic and reacting to the procedure. Alternatively, a propofol TIVA technique allows a steady level of anesthesia that is independent of ventilation and does not expose the OR personnel to waste anesthetic agents that inevitably egress from the airway around the bronchoscope. In some cases, a combined approach of sevoflurane in oxygen, as well as IV propofol, may be used. Often these children have very irritable airways because of the presence of the foreign body. The use of topical lidocaine (3 to 4 mg/kg) divided between the laryngeal structures and tracheal mucosa may be used to suppress airway reflexes and prevent coughing and bronchospasm.

Tracheocutaneous Fistula

Approximately 12% of children who have had their tracheostomy removed will retain a tracheocutaneous fistula.²⁷⁵ Surgical repair is generally required to remove the fistula track, followed by a primary closure of the defect.^276–278 In some, this may be accomplished with simple endoscopic cauterization.²⁷⁹ Usually there is a preliminary endoscopic assessment of the stoma site, removal of residual granuloma, and then a determination of the best approach to closure.²⁸⁰ A multilayered closure is commonly used to close the fistula,^281,282 whereas others recommend direct primary closure of the defect.²⁸³ The anesthesia approach generally includes maintenance of spontaneous respirations, and methods to avoid coughing or straining at the time of extubation. The main concern is the potential for the development of subcutaneous emphysema caused by residual air leak if the child coughs or strains.^{279,284–287} This complication may result in life-threatening pneumothorax or pneumomediastinum, which may occur up to 7 days following closure²⁸⁰; these complications require emergent removal of sutures, reestablishment of a tracheostomy, and thoracostomy and/or pericardial drainage.²⁸⁸ Some children may require postoperative ventilation, but most are extubated and admitted for observation after extubation and conclusion of the surgery. The vast majority have an uneventful recovery.