A Indications and Contraindications of Noninvasive Ventilation

Basically, NIV is applied in three different areas: in acute respiratory failure, as a weaning strategy, and in the management of the difficult airway.

B Different Types of Noninvasive Devices

Various types of face masks and helmets are widely used for administering NIV (Fig. 46-1).

Figure 46-1 A, Full face mask; B, total face mask; C, nasal mask; D, mouthpiece; E, nasal pillows; F, helmet.

(From Nava S, Hill N: Noninvasive ventilation in acute respiratory failure. Lancet 374:250–259, 2009.)

2 Noninvasive Positive-Pressure Ventilation via Helmet

The helmet consists of a cylindrical transparent part that is drawn over the patient’s head (e.g., CaStar, Starmed, Italy). While the helmet is closed, the lower part contains an elastic ring to ensure a tight seal at the patient’s neck (Fig. 46-2). Two openings with sideways fittings to ventilatory tubing allow supportive ventilation such as continuous flow or pressure support. The helmet is a noninvasive means of ventilation; the patient has a free view through the transparent helmet and can even wear glasses, with no fogging from the circulating air. A new model of the Castar helmet includes an additional round opening with a diameter of about 10 cm for nursing the patient’s face. This helmet was used as first-line intervention to treat patients with hypoxemic ARF, compared with NPPV via standard face mask.²⁴ Thirty-three consecutive patients without COPD and with hypoxemic ARF (defined as severe dyspnea at rest, respiratory rate >30 breaths/min, PaO₂/FIO₂ <200, and active contraction of the accessory muscles of respiration) were enrolled. The 33 patients and the 66 controls had similar characteristics at baseline. Eight patients (24%) in the helmet group and 21 patients (32%) in the facial mask group (P = .3) failed NPPV and were intubated. No patients failed NPPV because of intolerance of the technique in the helmet group, versus eight patients (38%) in the mask group (P = .047). Complications related to the technique (skin necrosis, gastric distention, eye irritation) were fewer in the helmet group compared with the mask group (no patients vs. 14 patients (21%), P = .002). The helmet allowed continuous application of NPPV for a longer period (P = .05). NPPV by helmet successfully treated hypoxemic ARF, with better tolerance and fewer complications than face mask NPPV.

Figure 46-2 Application of Castar helmet in healthy volunteer.

In another prospective clinical investigation in a general ICU, the feasibility and safety of fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) was tested during NPPV delivered by helmet in patients with ARF and suspected pneumonia.²⁵ Four adult patients with ARF underwent NPPV via the helmet and required fiberoptic BAL for suspected pneumonia. NPPV was delivered through the helmet in the pressure support ventilation mode. The specific seal connector placed in the plastic ring of the helmet allowed the passage of the bronchoscope, maintaining assisted ventilation. Arterial blood gas levels, pH, oxygen saturation, respiratory rate, heart rate, and mean arterial blood pressure (BP) were monitored during the study. Helmet NPPV avoided gas exchange deterioration during FOB and BAL, with good tolerance. During the procedure, heart rate increased by 5% and mean arterial BP by 7% over baseline; these levels returned to prebronchoscopy values immediately after the withdrawal of the bronchoscope. Endotracheal intubation was never required during the 24 hours after the procedure. BAL yielded diagnostic information in three of four patients. NPPV through the helmet allows a safe diagnostic FOB with BAL in patients with hypoxemic ARF, avoiding gas exchange deterioration, and endotracheal intubation.

Several special aspects of the helmet, such as the effects of direct exposure of external and middle ear to positive airway pressure, remain to be determined. Cavaliere and others²⁶ recommended earplugs in select NPPV patients treated with the helmet, especially during long-term support at high airway pressures. NPPV has become an integral part of daily ICU care for many patients with acute and chronic respiratory failure. However, the potential effectiveness of NPPV varies among different patient populations. The greatest benefit is seen in patients with pure hypercapnic respiratory failure, as seen in COPD patients. The more severe hypoxemia becomes, the less beneficial the effects observed. Clearly, further studies are necessary to identify patients with hypoxemic ARF who might benefit from NPPV.²⁷

The Rüsch 4Vent (Kernen, Germany) allows unrestricted field of view and minimum level of noise. Tubing and accessories are connected to the rigid ring of the 4Vent. Diffusers prevent the stream of gas from blowing directly into the patient’s face. Filters reduce the noise inside the helmet. Similar to the Castar helmet, the patient is able to speak and take liquid food and drinks. The supple material allows the helmet also to be worn lying down (Fig. 46-3).

Figure 46-3 Rüsch 4Vent helmet.

(Courtesy of Rüsch, Vienna, Austria.)

Advantages of NPPV include few air leaks, minimal cooperation required, and absence of nasal or facial skin damage. Disadvantages include rebreathing, gastric inflation followed by vomiting, dry eyes, noise, and asynchrony with pressure support ventilation, as well as shoulder discomfort induced by the straps.¹⁶

A Prelaryngoscopy Airway Assessment

Any factor in the patient’s history suggesting a difficult airway must be known before anesthesia induction, especially all diseases resulting in pharyngeal or laryngeal deformities (congenital abnormalities, surgical or traumatic deformities, laryngeal trauma, edema or tumors, goiter). As a first and rapid orientation, the simple “rule of threes” can be applied: if three fingers can be placed between the teeth, between the mandible and the hyoid bone, and between the thyroid cartilage and the sternal notch in neutral position, direct laryngoscopy should be straightforward.²⁸ Furthermore, more or less complex tests and scoring systems have been suggested to predict a difficult airway before anesthesia induction. The most frequently used tests are the Mallampati classification, thyromental distance, mobility of the cervical spine, and combined scoring systems (e.g., Wilson test) or multivariate risk indices^29–31 (Table 46-1).

Mallampati classification is the most common diagnostic test and is based on the evaluation of the relationship of tongue size relative to pharynx size, as follows³¹:

The operator should be aware that the risk of difficult airway is increased in class II and especially class III patients. In the original publication, Mallampati and colleagues³¹ reported excellent statistical results on the performance of the classification system. However, later investigations could not replicate these findings and report a high incidence of false-positive results.^32,33

Thyromental distance (according to Patil) is defined as distance between thyroid cartilage (Adam’s apple) and the mandible with the patient’s head and neck maximally extended. The authors measured thyromental distance before anesthesia induction in 75 patients and reported a minimum distance of 6.5 cm being necessary for a successful laryngoscopic approach. At a thyromental distance less than 6.0 cm, direct laryngoscopy is impossible; between 6.0 and 6.5 cm, the operator should be prepared for a difficult airway. Sensitivity of this test varies according to definition of the “danger zone” (i.e., thyromental distance <7.0 or <6.5 cm) and is reported in the range of 30% to 90%. In most studies, specificity ranges between 80% and 97%.^32,34 Thyromental distance is a useful diagnostic test with a relatively low intra- and inter-observer variation. However, the lacking stratification for patient height and weight makes data interpretation difficult.

Direct laryngoscopy without extension of the atlanto-occipital joint is impossible. Decreased mobility of the upper cervical spine (e.g., in patients with rheumatoid arthritis) is a major factor responsible for failed attempts of endotracheal intubation.³⁵ Nichol and Zuck³⁰ clearly demonstrated that a reduced atlanto-occipital distance is a major factor for a limited extension of head and neck. Assessment of cervical spine mobility is performed with the patient looking straight ahead and maximum mouth opening. The patient is now urged to flex and extend the head and neck. The angle between the extreme positions should be at least 90 degrees; otherwise, a difficult laryngoscopy must be assumed, with high specificity in the 90% range.

The range and freedom of mandibular movement and the architecture of the teeth have pivotal roles in facilitating laryngoscopic intubation, so Khan and colleagues³⁶ proposed the upper lip bite test. Patients were grouped according to the following findings: lower incisors can bite the upper lip above the vermilion line (class I); lower incisors can bite the upper lip below the vermilion line (class II); and lower incisors cannot bite the upper lip (class III). In 300 elective patients, the authors evaluated the new test with the Mallampati classification. Negative predictive value for both test groups was similar (98%), but the positive predictive value of the lip bite test was better (29% vs. 13%). To improve positive and negative predictive values of those screening tests, several authors proposed the combination of various risk scores. In 1988, Wilson and associates²⁹ published a screening test system, including patient weight, mobility of the cervical spine, and anatomic-physiologic parameters of the stomatognathic system (Table 46-2). According to the authors, difficult airways must be suspected with 2 or more cumulative points. This scoring system requires more extensive evaluation but results in improved statistical performance. In patients with a cumulative result of 2 points, sensitivity of 75% was observed.²⁹ Oates and coauthors³² reported specificity of 92%.

TABLE 46-2 Wilson’s Test

MMO, Maximum mouth opening; LJ, lower jaw; UJ, upper jaw.

From Wilson ME et al: Predicting difficult intubation. Br J Anaesth 61:211–216, 1988.

El-Ganzouri and associates³⁷ proposed a multivariate risk index, similar to the Wilson test. The authors recommended the following approach:

Statistical results demonstrate a relatively weak performance in clinical routine. Even combinations of tests or scoring systems combining several risk factors are prone to misjudgment for the individual patient.³⁴ The upper airway is a complex structure and consists of many anatomically relevant variables. Also, statistical performance of these tests is still unsatisfying; the operator might be warned of trouble. Closely evaluating the patient before anesthesia induction might prevent catastrophic “cannot intubate, cannot ventilate” situations.

B Oral vs. Nasal Endotracheal Intubation

Oral intubation and especially nasal intubation are characterized by special advantages and complications, with orotracheal intubation being currently favored by most anesthesiologists. Box 46-1 lists the contraindications for nasal intubation in critically ill patients.

The most common complication of nasotracheal intubation is nasal bleeding, occurring in about 45% of patients.³⁸ The incidence of bleeding can be reduced with adequate preparation (vasoconstrictors). In most cases, bleeding is self-limited, and no further intervention is needed. Other complications are necrosis of the tip or wing of the nose (up to 4% of patients) and complications induced by the impaired drainage of paranasal sinus secretions.³⁹ Nasotracheal intubation impairs the drainage of the maxillary sinus, resulting in congestion of secretions, followed within a few days by bacterial overgrowth and sinusitis. This typical complication of intensive care occurs within 8 days in 25% to 100% of transnasally intubated patients.^40,41 The incidence is closely related to the duration of endotracheal intubation, from 37% after 3 days to 100% after 1 week, with the majority resolving within 1 week after extubation.⁴² Therefore, in all ICU patients presenting with fever of unknown origin, a high index of suspicion for sinusitis must be maintained. Radiologic or ultrasound studies, including computed tomography (CT) scans, may be necessary to demonstrate the presence of fluid or inflammation. Bacterial sinus infection may ultimately lead to bacteremia and systemic inflammatory response. These infections tend to be polymicrobial, but often display a predominance of gram-negative bacilli (particularly Pseudomonas aeruginosa), Staphylococcus aureus, or fungi. Treatment includes removal of all nasal tubes and institution of appropriate antibiotic therapy, along with decongestant therapy. In some cases, surgical drainage may be necessary. Serious, but rare complications after nasotracheal intubation are accidental turbinectomy, intracranial placement, and retropharyngeal dissection.^43–45

Oral intubation, on the other hand, interferes greatly with oral and pharyngeal hygiene, and even small lesions of oral soft tissues may result in extensive bacterial or viral soft tissue infections (e.g., herpetic lesions).⁴⁶ Most authors agree that all complications typically seen with nasal intubation may also occur during orotracheal intubation, although at a significantly lower incidence. Therefore, oral endotracheal intubation is the preferred route of tube passage, and nasal intubation is reserved for special indications, mainly short-term ventilatory support in oral surgery. For patients requiring intubation for more than 7 days, the nasotracheal route should always be avoided.⁴⁷

C Choosing the Correct ETT Size

According to literature, there is a clear association between endotracheal tube diameter and the incidence of laryngeal complications. Injury is located mainly in the posterior part of the glottis, where pressures up to 200 or 400 mm Hg are exerted by poorly deformable ETTs.⁴⁸ This pressure is reduced by the use of softer ETTs with a smaller diameter. In routine anesthesia patients, use of a smaller ETT reduces the incidence of postoperative sore throat, presumably because of the decreased pressure at the ETT-mucosal interface. Stout and associates⁴⁹ studied 101 patients randomized to larger (9 mm for male, 8.5 for female) or smaller (7 mm for male, 6.5 mm for female) endotracheal tubes, and the incidence of postoperative sore throat was 48% (large ETT) versus 22% (small ETT). No ventilatory difficulties were observed in either group.

The limiting factor for minimizing ETT diameter is the increased flow resistance and work of breathing. The pressure gradient required to generate gas flow can be calculated according to the Hagen-Poiseuille relationship, in which the rapidity of gas flow is directly proportional to the square of the ETT diameter (D) and the pressure (P) and indirectly to the ETT length and gas viscosity (valid only in laminar flow conditions). In other words, the pressure gradient through the airways proportionally rises with flow, viscosity, and ETT length but increases exponentially when ETT radius decreases. Viscosity of the gas administered has clinical consequences; with lower viscosity, a lower pressure gradient necessarily results in a lower airflow resistance. For example, gas mixtures with a high percentage of helium are often used to overcome upper airway obstruction (e.g., from tracheal compression or stenosis) and to treat the most severe status asthmaticus.^50,51

In all patients, endotracheal intubation artificially increases airway resistance, because ETT inner diameter (ID) is smaller than tracheal diameter. Usually, ETT length exceeds length of the natural airways. Resistance is further increased by the curved design of the tubes necessary to resemble the patient’s airway. Resistance measured using curved tubes is about 3% higher compared with straight tubes.⁵² Therefore, the pressure gradient to generate gas flow is minimized by using an ETT with a larger diameter, short length, and straight design. Flow resistance can be translated in work of breathing, which is inversely proportional to ETT diameter (Fig. 46-4). The non-elastic work of breathing is increased twofold by using 7.0 mm–ID ETT and onefold by using an 8.0 mm–ID ETT versus a 9.0 mm–ID ETT.⁵³ With respect to gas flow, it is warranted to use as large an ETT as is practical for patients presenting with respiratory dysfunction; a short tracheal cannula with ID of 9.0 to 10 mm is best.

Figure 46-4 Driving pressure required to produce a flow rate of air versus internal diameter (ID) of endotracheal tubes.

(From Nunn JF: Applied respiratory physiology, ed 3, Boston, 1987, Butterworths.)

D Drugs Used for Sedation and Analgesia

In general, less is more in conscious sedation for airway management. Drugs must be administered in dosages not interfering with protective reflexes and patient cooperation. Therefore, short-acting drugs with a potential antidote should be used.

The presumption of a “full stomach” in emergency intubations dictates the use of a rapid-sequence induction (RSI) technique. Cricoid pressure and laryngoscopy at the earliest possible moment place increased demands on the physician preparing to intubate the patient.⁶³ The ICU patient presents with even more risk factors than the routine OR patient. With facial distortion, swelling, secretions, and mandibular or cervical spine injury, ICU patients present the most challenging airway management problems.

Stimulation of the airway with a laryngoscope and ETT presents an extremely noxious stimulus.⁶⁴ This stimulation causes “pressor response” and results in hypertension and tachycardia. In critically ill patients with limited reserves for adequate tissue oxygenation, this pressor response may induce myocardial and cerebrovascular injury.⁶⁵ This physiologic stress after airway management may unmask relative hypovolemia or vasodilatation and may result in post-intubation hypotension.⁶⁶ Endotracheal intubation also can provoke bronchospasm and coughing, possibly aggravating underlying conditions such as asthma, intraocular hypertension, and intracranial hypertension. Patients at risk for adverse events from airway manipulation benefit from pre-induction drugs.⁶⁷

We prefer the combination of low-dose midazolam (0.1 µg/kg) and an opioid such as fentanyl (2 µg/kg). Fentanyl is the most frequently used opioid because of its rapid onset and short duration of action. Fentanyl and its derivatives, sufentanil and alfentanil, can cause rigidity of chest wall, but this rigidity seems to be associated with higher doses and rapid opioid injection. Fentanyl can be antagonized rapidly using naloxone,⁶⁸ whereas midazolam can be antagonized using flumazenil.

Remifentanil is a novel µ-receptor agonist that has been used in surgical and obstetric analgesia for more than a decade. Its pharmacokinetics suggests that remifentanil may be an ideal opioid. Notably, its unique features include rapid onset of action (~1 minute), rapid degradation by tissue and plasma esterases, and half-life of approximately 3 minutes.^69,70 Infusion of 0.05 to 0.1 µg/kg/min produces blood concentrations of 1 to 3 ng/mL. Rapid onset and elimination of remifentanil facilitate its effective and safe use during airway management in the ICU. Several studies focused on remifentanil as a sole sedative and analgesic agent in the ICU setting. Puchner and coworkers⁷¹ prospectively studied remifentanil (0.1-0.5 µg/kg/min) alone versus fentanyl plus midazolam for fiberoptic intubation. Fiberoptic nasal intubation was possible in all patients, with a better-suppressed hemodynamic response and tolerance of ETT advance in the remifentanil group. Recall was significantly more common in the remifentanil group. A combination of remifentanil and midazolam or propofol is a valuable approach.⁷²

Lallo and coworkers⁷³ recently studied 60 patients requiring fiberoptic nasotracheal intubation, randomized to target-controlled infusions of propofol or remifentanil. Both agents can be rapidly titrated to achieve good intubating conditions and patient comfort. In addition, remifentanil preserves patient cooperation, making it safer when spontaneous ventilation is paramount. Yeganeh and associates⁷⁴ enrolled 22 patients who had cervical trauma and semi-elective maxillofacial surgery and administered remifentanil with target-controlled or manually controlled infusion techniques. They recommended remifentanil infusion to provide good conscious sedation, but target-controlled remifentanil infusion seems to provide better conditions compared with manually controlled remifentanil infusion and is easier to use.

Alternative drugs suitable for ICU airway management and even awake fiberoptic intubation are (S+)-ketamine and propofol.⁷⁵ Propofol is a rapid-acting, lipid-soluble induction drug that induces hypnosis in a single arm-brain circulation time. In patients with cardiac comorbidities and limited physiologic reserve, the use of propofol can be associated with significant hypotension. Causes of hypotension are reduced systemic vascular resistance and possibly depressed inotropy.⁷⁶ In an analysis of 4096 patients undergoing general anesthesia, Reich and associates⁷⁷ reported that the use of propofol was a statistically significant predictor of hypotension. Furthermore, in 2406 patients with retrievable outcome data, prolonged in-hospital stay and death were more common in those who experienced hypotension.⁷⁷ Therefore, use of propofol may have special risks in high-risk patients with known cardiac dysfunction.⁷⁸

Ketamine is a rapid-acting, dissociative anesthetic agent (similar to phencyclidine) with potent amnestic, analgesic, and sympathomimetic effects.⁶⁷ Ketamine can cause realistic hallucinations and extreme emotional distress. This may be prevented with the obligatory combination of a benzodiazepine. The sympathomimetic effects of ketamine may produce cardiac ischemia by increasing cardiac output. Consequently, use of ketamine should be avoided in patients with cardiac dysfunction. Leykin and others⁷⁹ found that the administration of ketamine resulted in excellent intubation conditions in patients undergoing elective surgery compared with sodium pentothal. In a prospective, randomized clinical trial, Ledowski and Wulf⁸⁰ reported that the combination of ketamine with rocuronium and etomidate resulted in superior intubation conditions. This combination may be useful in treating hemodynamically unstable patients in the ICU setting, when succinylcholine is contraindicated.²¹ The use of ketamine in patients with increased intracranial pressure is only recommended in mechanically ventilated patients.⁸¹ Ketamine is associated with realistic and truthful nightmares. In this context, the combination with midazolam seems to be an obligatory recommendation. Currently, an S(+) enantiomer of ketamine is available. This enantiomer seems to be free of these clinically relevant side effects although use of these S(+) enantiomers is still recommended in combination with midazolam.

Etomidate provides good intubation conditions with only moderate hemodynamic depression in patients undergoing RSI.⁸² Etomidate inhibits adrenosteroid production through the inhibition of mitochondrial hydroxylase, after continuous or even single administration.^83–85 Cuthbergson and colleagues⁸⁶ recruited 500 patients to a multicenter, randomized, double-blind, placebo-controlled trial. The use of bolus etomidate was associated with an increased incidence of inadequate response to corticotrophin and is likely associated with an increase in mortality. Therefore, the authors recommend extreme caution in the use of etomidate in critically ill patients with septic shock.⁸⁶ Roberts and Redman⁸⁷ and Bloomfield and Noble^88,89 also questioned any use of etomidate in critically ill patients.

Dexmedetomidine is increasingly used as a sedative for monitored anesthesia. Advantages include its analgesic properties, “cooperative sedation,” and lack of respiratory depression. Dexmedetomidine is also increasingly used in RSI and awake intubation, with promising studies showing a beneficial effect.^90,91 However, long-term observational studies are still lacking, and the current scientific level is too weak to recommend routine use of dexmedetomidine.

Muscle relaxants are also used in emergency airway management in the ICU. If endotracheal intubation fails, the merits of preserving spontaneous ventilation versus optimized intubating conditions using non-depolarizing muscle relaxants should be considered.

Succinylcholine is a very-rapid-acting, polarizing muscle relaxant enabling excellent intubation conditions in less than 1 minute.⁹² Unfortunately, it has serious side effects, including the possibility of triggering malignant hyperthermia. The use of succinylcholine is contraindicated in patients with acute major burns, upper or lower neuronal lesions, prolonged immobility, massive crush injuries, and various myopathies.²¹ Benumof and associates⁹³ clearly demonstrated that even the short duration of action of succinylcholine is too long, and critical hemoglobin desaturation will occur before return to an unparalyzed state, even after a 1-mg/kg dose.⁹³

Rocuronium is the most widely used non-depolarizing neuromuscular blocking agent. The recommended dosage of “normal” intubation is 0.6 mg/kg. For RSI, higher dosages up to 1.2 mg/kg are necessary and provide excellent intubation conditions within 1 minute.⁹⁴ A meta-analysis by the Cochrane Collaborative Group concluded that succinylcholine created superior intubation conditions compared with rocuronium.⁹⁵ The only absolute contraindication against the use of rocuronium is allergy to aminosteroid neuromuscular drugs. A major advantage of rocuronium is the possibility of rapid and complete reversal of even deep neuromuscular block by the administration of sugammadex.⁹⁶ Based on a systemic review by Chambers and others,⁹⁷ the use of sugammadex in combination with high-dose rocuronium is efficacious.

E Awake Endotracheal Intubation

Successful awake intubation depends on proper patient preparation. Extensive psychological support and clear explanation about reason for and management of awake intubation are necessary and helpful in the ICU setting.

The airway is topically anesthetized with 5% to 10% lignocaine, which is sprayed with a flexible nozzle into the posterior pharynx to reduce coughing and buckling during intubation. If a fiberscope is used, the larynx is then sprayed with 2 mL of lignocaine 2% administered through the working channel of the fiberscope, after which the scope is advanced into the trachea. Thereafter, a second spray is applied into the trachea before the ETT is advanced. Alternative approaches include blockade of superior laryngeal nerve or lingual nerve and transtracheal anesthesia.

Once the patient is properly prepared, any of the intubation techniques listed in Box 46-2 can be chosen according to the operator’s preference.^98–102

In case the first attempt of awake intubation fails because of equipment/operator failure or poor patient cooperation, the following options should be considered: a modified method for awake intubation (e.g., change from blind nasal to fiberoptic approach), induction of general anesthesia, and transition to a fiberoptic-guided intubation method. We believe that the first choice for awake airway management is fiberoptic oral or nasal intubation. If oral intubation is performed, a conduit (i.e., Ovassapian fiberoptic intubating airway) may be used to facilitate fiberscope and ETT insertion. Additionally, a 4 × 4 gauze pad may be used to pull the tongue forward.

A valuable alternative approach is the insertion of the intubating laryngeal mask airway (ILMA) under local anesthesia and light sedation. Intubation is then performed blindly or using a fiberscope inserted through the LMA. Langeron and coworkers¹⁰³ prospectively compared ILMA intubation with fiberoptic intubation in patients with difficult airway and reported similar success rates (>90%) and durations for both techniques. Another interesting approach is the combination of Fastrach and lighted stylet. Dimitriou and associates¹⁰⁴ studied 44 of 11,621 patients in whom three attempts of direct laryngoscopy failed. In all these patients, an ILMA was inserted and sufficient ventilation was possible in all patients after a maximum of two attempts. Thereafter, a well-lubricated silicon ETT loaded with a flexible lightwand was introduced. Lightwand intubation was successful at the first attempt in 38 of 44 patients, at the second attempt in three patients, and at the third to fifth attempt in two. Intubation failed in only one patient. Finally, if all those alternatives fail, the establishment of a surgical airway should be considered.

F Assessment of Correct ETT Placement

Esophageal intubation is a major complication of airway management and can result in severe brain damage or even death. Evaluating the U.S./American closed-claims database (5480 claims), Cheney and colleagues¹⁰⁵ reported the changing trends in anesthesia-related death and permanent brain damage. In the 1980s, 11% of claims associated with death or brain damage involved esophageal intubation, fortunately decreasing to 3% in the 1990s. This reduction was attributed to the introduction of end-tidal carbon dioxide partial pressure (PETCO₂) monitoring in the 1990s (Fig. 46-5).

Figure 46-5 Percentage of inadequate ventilation, esophageal intubation, and difficult intubation events associated with death or brain damage in anesthesia-related insurance claims.

(From Cheney FW. Changing trends in anesthesia-related death and permanent brain damage. ASA Newslett 66:6–8, 2002.)

Esophageal intubation is an issue even in sufficiently equipped ICUs. Schwarz and colleagues¹⁰⁶ studied almost 300 emergency intubations in an ICU setting and reported esophageal intubation in 8% of cases (ETT misplacement was corrected in all patients before the onset of hypoxemia).

Techniques for clinical evaluation of ETT position include the following:

Radiographic investigation is of limited value because of the delay in diagnosis. Fiberoptic evaluation needs special equipment and preparation and is time-consuming. Acoustic reflectometry is a promising new approach with excellent results, at least in experienced hands. Rafael and coworkers¹¹⁷ studied acoustic reflectometry in 200 adult intubated patients and reported a 99% correct tracheal and a 100% correct esophageal identification rate. Currently, CO₂ monitoring comes closest to the ideal monitor of correct ETT positioning. CO₂ monitoring can be performed either colorimetrically by relatively inexpensive single-use CO₂ detectors (e.g., Easy Cap, Tyco Healthcare; or Colibri, ICOR AB, Bromma, Sweden) or by capnography using infrared absorption.^118,119 Ventilation is assessed as PETCO₂ approximates arterial CO₂ partial pressure (PaCO₂) within 2 to 6 mm Hg in normal lungs. Unfortunately, in many disease states, this discrepancy increases significantly. The concentration of CO₂ expired is determined by CO₂ production (e.g., body temperature, muscle tone), CO₂ transport (e.g., circulation, pulmonary perfusion), and CO₂ elimination (pulmonary and airway integrity). Therefore, absence of PETCO₂ indicates esophageal intubation, circuit disconnection, cardiac arrest, or airway obstruction. A false-positive result may be obtained after gastric inflation with CO₂ containing gas or digestion of carbohydrate-enriched beverages. ETT-misplacement can be excluded by observing a normal PETCO₂ waveform for three to six consecutive breaths.

Knapp and associates¹²⁰ investigated four different methods—auscultation, capnographic PETCO₂ determination, self-inflating bulb, and transillumination using Trachlight—for the verification of correct ETT positioning in 152 examinations in an ICU setting. Only PETCO₂ monitoring was reliable for the verification of tracheal ETT placement (Fig 46-6). A poorer performance was only reported for prehospital and in-hospital cardiac arrest patients. However, end-tidal CO₂ concentrations are closely correlated with resuscitation outcome in this special setting.¹²¹

Figure 46-6 Error rates of experienced and inexperienced examiners obtained by evaluating endotracheal tube placement using one of four methods: auscultation, end-tidal carbon dioxide pressure (ETCO₂), self-inflating bulb, and Trachlight.

(From Knapp S, Kofler J, Stoiser B, et al: The assessment of four different methods to verify tracheal tube placement in the critical care setting. Anesth Analg 88:766–770, 1999.)

In conclusion, correct tracheal ETT placement can therefore only unequivocally be assured by a physiologic PETCO₂ signal for several consecutive breaths (eventually combined with an esophageal detector device in the prehospital setting), by direct visualization of the ETT between the vocal cords, or by fiberoptic visualization of tracheal cartilaginous rings and carina. All other techniques may provide useful additional information but are prone to errors and misinterpretation.

A Esophageal-Tracheal Combitube

The esophageal-tracheal Combitube (ETC) is a double-lumen airway (“pharyngeal” and “distal” lumen) invented by Frass and coworkers,¹⁴³ equipped with a pharyngeal balloon and a distal cuff (Covidien, Mansfield, Mass). The ETC is designed for blind insertion into the patient’s esophagus or trachea. In more than 95% of all blind insertions, the ETC enters the esophagus. After insertion, the pharyngeal balloon is inflated (maximum, 85/100 mL air) and seals against the oral cavity, while the distal cuff (5-12/15 mL air) prevents gastric inflation. Test ventilation is started via the pharyngeal lumen (i.e., supraglottic ventilation). Absence of breath sounds and gastric inflation indicate the rare case where the ETC has blindly entered the trachea. Ventilation is attempted via the distal lumen, the distal cuff blocked with the minimum amount of air providing adequate seal, and the ETC used as a conventional ETT. Two different ETC sizes are available: a small-adult model (37 French, Combitube SA) for women and men ranging in height from 120 to 200 cm and a 41-F model for taller patients.^144,145

The ETC has been used extensively in emergency situations, as well as during routine surgery.^144,146,147 The authors recommend sufficient training during elective surgery before using the airway in emergency situations.^145,148,149 In routine cases, the ETC might be inserted using a standard laryngoscope to reduce the risk of tissue injury.^150,151 Contraindications for the use of the ETC are esophageal pathologies, ingestion of caustic substances, and central airway pathologies. Disadvantages are the lack of access to the patient’s airways (suctioning of tracheal secretions impossible), lack of a pediatric ETC, and risk of venous stasis and soft tissue (tongue) swelling after prolonged use. The former limitations will be eliminated by the introduction of a redesigned ETC enabling fiberoptic access to the patient’s airways and a pediatric version of the ETC.^152,153

Advantages of the Combitube include protection against aspiration of gastric contents and the applicability of high airway pressures.¹⁵⁴ The ETC might stay in place for up to 8 hours, providing time for further decision making.¹⁵⁵ Changing the ETC for a definitive airway (regular ETT or tracheal cannula) might be done by an attempt of direct laryngoscopy, fiberoptically, or surgically (elective tracheostomy or cricothyrotomy).^152,156

Recently, the EasyTube has been released (Teleflexmedical Ruesch). It is similar to the Combitube but offers certain advantages: The “pharyngeal” lumen of the EasyTube ends just below the oropharyngeal balloon. Therefore, the “tracheo-esophageal” lumen is thinner than that of the Combitube, which carries the two lumens down to the end. Since the distal single lumen of the EasyTube is significantly thinner, the potential danger of mucosal damage is minimized. Furthermore, the oropharyngeal balloon is latex free. The EasyTube comes in two sizes. The 28-F EasyTube (“pediatric size”) is available for patients ranging in height from 90 to 130 cm; the 41-F EasyTube is designed for patients taller than 130 cm. A fiberscope can be passed through the so-called pharyngeal lumen because it is open at the distal end. This feature allows inspection of the trachea and possible replacement of the EasyTube using a guidewire, in addition to a larger suction catheter via both lumens (14-F suction catheter in 41-F EasyTube). The EasyTube has been used in a few cases of difficult intubation at the ICU (see Chapter 27).

B Laryngeal Mask Airway

The laryngeal mask airway (LMA North America, San Diego) was presented in 1983, gained widespread popularity, and is currently used extensively during general anesthesia.^142,157,158 The LMA may be placed for three different reasons: as a routine airway and ventilatory device, as an emergency airway in cannot-intubate, cannot-ventilate situations or as a conduit for endotracheal intubation. Advantages of LMA use as a routine airway have been demonstrated clearly over conventional face mask ventilation. Tidal volumes administered were higher and problems associated with airway management (difficulties in maintaining airway or SpO₂ ≥95%) less frequently encountered during LMA use compared with regular face mask.¹⁵⁹ LMA works well under these circumstances, because exact positioning is not crucial for a clinically acceptable patent airway.

Furthermore, the potential use of this recent airway in respiratory emergency situations has been recognized early.¹⁶⁰ Leach and associates¹⁶¹ described use of the LMA as the immediate airway in cardiopulmonary resuscitation, and their findings were confirmed by a larger investigation.¹⁶² A multicenter study was undertaken to assess the potential value of the LMA when inserted by ward nurses during resuscitation as a method of airway management, prior to the arrival of the advanced life support team with endotracheal intubation capability; 130 nurses were trained and 164 cases of cardiac arrest studied. The LMA was inserted at the first attempt in 71% and at the second attempt in 26% of patients. Satisfactory chest expansion occurred in 86%. The mean interval between cardiac arrest and LMA insertion was 2.4 minutes. Regurgitation of gastric contents occurred before airway insertion in 20 patients (12%) and during insertion in three (2%).¹⁶²

Therefore, the LMA has been incorporated into the ASA algorithm and might be inserted as a conduit for fiberoptic endotracheal intubation in the awake or anesthetized patient who cannot be conventionally intubated (mask ventilation may or may not be possible) and as a non-emergency or emergency airway in the anesthetized patient¹⁴² (Fig. 46-8).

Figure 46-8 Laryngeal mask airway (LMA) and ASA DA algorithm.

(From Benumof JL: Laryngeal mask airway and ASA Difficult Airway Algorithm. Anesthesiology 84:686–699, 1996.)

Especially for those patients with supraglottic pathologies and unfavorable anatomy for face mask ventilation or endotracheal intubation, an early LMA insertion should be considered. Drawbacks of the LMA include the lack of access to the patient’s central airways, risk of aspiration, limited positive airway pressures due to the often inadequate seal, and the need for training. Moreover, the LMA is a supraglottic airway device and thereby unable to establish adequate gas exchange in patients with central airway obstruction.

In the meantime, several modifications of the LMA have been proposed and have been or will be introduced into clinical routine. The ILMA differs from conventional LMAs by having a wider, shorter stainless steel tube; a handle to steady the device; and an epiglottic elevating bar (movable flap fixed to upper rim of mask). The ILMA is accepting cuffed ETTs up to ID of 8.5 mm, enabling blind or fiberoptic intubation using the correctly placed ILMA as a conduit. Success rates for blind ILMA intubation in the 75% to 90% or greater range have been reported.^103,163,164

The ILMA has therefore been recommended as a rescue device for emergency airway management. Ferson and colleagues¹⁶³ used the ILMA in 254 patients with different types of difficult airway. Insertion of the ILMA was accomplished in three attempts or fewer in all patients. The overall success rates for blind and fiberoptically guided intubations through the ILMA were 96.5% and 100.0%, respectively. Repeated “blind” intubation attempts with the ILMA resulted in esophageal perforation in one elderly patient.¹⁶⁵ Therefore, for blind ILMA intubation, the specially designed silicon tube with rounded bevel should be preferred, because success rates exceed those encountered with standard reinforced tubes.¹⁶⁶ Muscle relaxation is not needed for blind ILMA intubation but increases success rates.¹⁶⁶

C Transtracheal Jet Ventilation

In brief, transtracheal jet ventilation (TTJV) is performed using a 16- or 14-gauge catheter, and a 1.5- to 3.5-bar oxygen source (equipped with pressure regulator) in combination with noncompliant tubing. The TTJV catheter is inserted through a cricothyroid puncture, and correct tracheal placement is verified by the aspiration of 20 mL of free air. Noncompliant tubing is then connected and manual oxygen inflation started at an inspiratory rate less than 1 second (~0.5 second) and an inspiratory/expiratory time ratio of 1 : 3 (to ensure enough time for passive exhalation). Alveolar ventilation is achieved by bulk flow of oxygen through the cannula, as well as translaryngeal entrainment of room air (Venturi effect). For example, use of a 16-gauge cannula and a driving pressure of 3.5 bar results in a gas flow of approximately 500 mL/sec.¹⁶⁹ Therefore, facilitation of passive exhalation by maintaining patency of natural airways is of major importance to avoid overinflation and pulmonary barotrauma. Therefore, nasopharyngeal and oropharyngeal airways are inserted, maximum jaw thrust is well maintained throughout the entire procedure, and expiratory chest movements are observed continuously.

Performed in elective as well as emergency situations, the major indications for TTJV are lack of equipment for conventional airway management, the “cannot ventilate, cannot intubate” situation, ventilatory support during upper airway surgery, or support during endotracheal intubation by other techniques (e.g., ventilation during prolonged fiberoptic intubation). Complications of TTJV during elective application are rare but occur frequently during emergency TTJV (mainly limited to tissue emphysema). Monnier and colleagues¹⁷⁰ used high-frequency TTJV for ventilatory support during elective laser surgery for laryngeal and subglottic lesions and observed only one complication in 65 patients (mediastinal emphysema). Smith and coworkers,¹⁷¹ however, reported a 29% complication rate in 28 emergency TTJV patients (exhalation difficulty in 14%, subcutaneous emphysema in 7%, mediastinal emphysema in 4%, arterial perforation in 4%). Other complications of TTJV (e.g., esophageal puncture, bleeding, hematoma formation) have been reported but rarely occur.

D Emergency Surgical Airway

Rapid-sequence induction is the standard for emergency airway management in ICUs and EDs. Reported success rates of RSI are 97% to 99%, and an emergency surgical airway is only necessary in 0.5% to 2% of patients.^140,172 Sakles and associates¹⁴⁰ evaluated 610 patients requiring emergency airway management in the ED during a 1-year period; RSI was used in 515 (84%). A total of 603 patients (98.9%) were successfully intubated, and only seven patients could not be intubated and underwent cricothyrotomy. Therefore, anesthesiologists and intensive care physicians have only limited experience with surgical airway management. The ASA algorithm has proved to be an invaluable tool, but only briefly addresses the circumstances when a patient must be intubated immediately regardless of the difficulties presented. Since performance of a surgical airway is the final pathway of all airway algorithms, cricothyrotomy must be mastered by all clinicians involved in emergency airway management. Surgical airway management comprises percutaneous dilatational cricothyrotomy or tracheostomy using the Seldinger technique, surgical cricothyrotomy, or surgical tracheostomy. In emergency situations and in cases of unexpected intubation failure in the ICU, surgical or percutaneous cricothyrotomy using the Seldinger technique is preferred over tracheostomy and enables rapid and easy airway access and restoration of adequate gas exchange and ventilation.

2 Surgical Cricothyrotomy

The vasculature is rich overlying the cervical trachea but is strikingly absent over the cricothyroid membrane (CTM). Surgical cricothyrotomy can be performed only after correct identification of the CTM between thyroid and cricoid cartilage; the vertical length of the membrane is about 0.7 to 1.0 mm. The set of instruments used should be simple: scalpel with no. 11 blade, tracheal hook, Trousseau dilator, and cuffed tracheostomy tube. The most common technique is the “no drop” technique, where the larynx and trachea are immobilized by the operator’s hand throughout the procedure. Other techniques have been proposed (e.g., four-step technique), but the no-drop technique has proved its value with the following six steps (Fig. 46-9)¹⁷⁶:

Step 1: Identify the CTM. Key landmark is the laryngeal prominence (Adam’s apple), which is easier to palpate in men than in women. It can be identified in the midline at the junction of upper and middle third of the anterior neck. Thumb and long finger stabilize the larynx, while the index finger is run down the anterior surface of the thyroid cartilage until the concavity of the CTM is reached.

Step 2: Immobilize the larynx by holding the superior horns of the thyroid between thumb and long finger, and incise the skin vertically (vertical incision 2-3 cm in length provides maximum flexibility and minimum trauma). Vertical skin incision should be made through skin and subcutaneous tissues and not into the airway. Thereafter, the CTM is again identified using the index finger. Several authors prefer to leave the index finger in the wound even during the dissection of the membrane (enables the membrane incision directly caudal to the index finger).

Step 3: Incise the CTM transversely in its distal third whenever possible (avoidance of superior thyroid artery). The incision should be wide enough to permit easy insertion of the cannula (1.5-2 cm).

Step 4: Insert the tracheal hook transversely into the incised membrane, then rotate it 90 degrees to the midline (some authors waive use of tracheal hook in open cricothyrotomy). The hook strictly immobilizes the larynx and brings the opening within the membrane closer into the field of view.

Step 5: Insert the Trousseau dilator into the airway for several millimeters, then open it to dilate the airway. Some prefer opening the branches in a rostrocaudal direction because most resistance to cannulation is encountered between thyroid and cricoid. However, transverse dilation is also possible.

Step 6: Insert the respective tracheal cannula with the right hand between the prongs opened with the operator’s left hand. Slight twisting of the cannula, with a 90-degree rotation of the Trousseau dilator, may be necessary to advance the tracheal cannula safely.

Figure 46-9 Six steps in performing surgical cricothyrotomy.

(From Walls RM, Gibbs MA: Surgical airway. Semin Anesth Periop Med Pain 20:183–192, 2001.)

As mentioned, Seldinger as well as open cricothyrotomy are characterized by several pitfalls; both techniques require training in the manikin or better, in human cadavers, and the individual operator must choose the preferred technique. Several authors prefer the open approach because a cuffed cannula can be used, and endotracheal suctioning or bronchoscopy is possible.

In conclusion, the ASA Difficult Airway Algorithm was approved by the ASA House of Delegates in October 1992 and became effective July 1993.¹ Every patient needs to be screened for difficult airways before anesthesia induction, and when difficulties are expected, airways need to be secured with the patient still awake (using fiberoptic scope in most cases). If difficulties are encountered with the patient already anesthetized, refrain from repeated and forceful attempts at direct laryngoscopy, and instead consider alternative methods. If a “cannot ventilate, cannot intubate” situation is encountered, either LMA or Combitube must be inserted immediately. Further alternatives are institution of TTJV or immediate surgical access to the patient’s airway. The most important point is to be alert and have a plan B and C prepared in case difficulties arise.

A Reasons for Performing Tracheostomy

Tracheostomy (or tracheotomy) is one of the most frequently performed elective surgical procedures in ICU patients, done in almost 10% of intubated patients. Tracheostomy is generally done for the following four reasons²⁰²:

TABLE 46-6 Major Complications of Prolonged Translaryngeal Intubation

NA, Not available.

^* After 10 days of endotracheal intubation.

^† From 0.5% to 5% of all tracheoesophageal fistulas are caused by endotracheal intubation.

From Shirawi N, Arabi Y: Bench-to-bedside review: early tracheostomy in critically ill trauma patients. Crit Care 10:201, 2006.

The issue of long-term translaryngeal intubation versus tracheostomy now favors secondary tracheostomy, although the adequate time point is still under discussion. In 2010, Durbin²⁰² listed benefits of changing from a translaryngeal ETT to a tracheostomy tube in patients who require prolonged intubation. However, the evidence level for most topics discussed is “poor” and comes mainly from uncontrolled trials (Table 46-7).

TABLE 46-7 Benefits of Changing from Translaryngeal Endotracheal Tube to Tracheostomy Tube in Patient Requiring Prolonged Intubation

RCT, Randomized controlled trial.

From Durbin CG Jr: Tracheostomy: why, when, and how? Respir Care 55:1056–1068, 2010.

B Timing of Tracheostomy

In 1989, at the Consensus Conference on Artificial Airways in patients receiving mechanical ventilation, the indications for nasal or oral ETTs and tracheostomy tubes were forged; “if the need for an artificial airway is anticipated to be greater than 21 days, a tracheostomy should be preferred.”²⁰⁴ With the introduction of percutaneous methods, the issue of translaryngeal intubation versus tracheostomy shifted to the best time point to perform tracheostomy.

In a prospective multicenter randomized trial, Rumbak and coworkers²⁰⁵ assigned 120 patients to early (within 48 hours after arrival at ICU) and delayed (14-16 days after arrival) percutaneous dilatational tracheostomy. Early tracheostomy was associated with significantly less mortality, nosocomial pneumonia, unplanned extubation, oral and laryngeal trauma, and a shorter duration of mechanical ventilation and ICU admission (Tables 46-8 and 46-9). Prospective studies by Arabi,²⁰⁶ Bouderka,²⁰⁷ and Rodriguez²⁰⁸ and their associates approved the shorter duration of mechanical ventilation in patients with earlier tracheostomy. In a systemic review and meta-analysis of five randomized trials, Griffith and colleagues²⁰⁹ found that early tracheostomy is associated with 8.5 fewer days of mechanical ventilation and 15 fewer days in the ICU. However, there were no significant differences in mortality or nosocomial pneumonia rates.

TABLE 46-8 Early vs. Delayed Percutaneous Dilatational Tracheostomy

There was a significant difference between the early tracheotomy groups and the prolonged translaryngeal intubation group in outcome measures. Some patients were sent to a step-down while still on mechanical ventilation.

^* P <.005.

^† P <.001.

From Rumbak MJ et al: A prospective, randomized study comparing early percutaneous dilational tracheotomy to prolonged translaryngeal intubation (delayed tracheotomy) in critically ill medical patients. Crit Care Med 32:1689-1694, 2004.

TABLE 46-9 Cause of Death in Critically Ill Medical Patients Receiving Early Tracheotomy or Delayed Translaryngeal Intubation*

^* More patients died of ventilator-associated pneumonia in the prolonged translaryngeal group than the early tracheotomy group.

From Rumbak MJ et al: A prospective, randomized study comparing early percutaneous dilational tracheotomy to prolonged translaryngeal intubation (delayed tracheotomy) in critically ill medical patients. Crit Care Med 32:1689–1694, 2004.

In contrast, most studies could not demonstrate definitive advantages of early (days 3-5) versus later (days 10-14) tracheostomy.^210,211 In a systematic review, Maziak and colleagues²¹² identified 48 possibly relevant articles of 8153 citations; five of the 48 articles met the inclusion criteria. After data review, the authors found no significant advantages of early (days 2-7) versus late (>days 4-14) tracheostomy, concluding insufficient evidence exists to support that the timing of tracheostomy alters the duration of mechanical ventilation or extent of airway injury. In a 2006 meta-analysis comparing early and late tracheostomy in ICU trauma patients, Dunham and Ransom²¹³ found no differences in mortality, nosocomial pneumonia, duration of mechanical ventilation, laryngotracheal pathology rates, or length of stay in hospital.

In a questionnaire answered by 48 Swiss ICUs (1995-1996; 90,412 patients and 243,921 ventilator-days), 10% of all patients who were ventilated longer than 24 hours underwent tracheostomy.²¹⁴ The majority of tracheotomies (35%) were performed in the second week of critical illness. However, 68% of all interviewed physicians would also perform an early (<day 7) tracheostomy if indicated (expected longer ICU course). The authors concluded that tracheostomy in Swiss ICUs is far from being standardized with regard to indication, timing, and choice of technique.

A randomized prospective study is required to examine the need for and the timing of tracheostomy in patients requiring prolonged mechanical ventilation. The findings of such a study would have significant impact on the clinical practice and hospital costs.²¹² Until then, the following recommendations of the Consensus Conference of 1989 are still valid²⁰⁴:

C Tracheostomy Techniques

Basically, two approaches are available for performing tracheostomy: conventional surgical tracheostomy (ST) and percutaneous dilatational tracheostomy (PDT). During the past 15 years, standard tracheostomy using an open surgical approach and the percutaneous techniques were used in parallel. Meanwhile, the use of PDT is still expanding, and several experts suggest PDT as the new gold standard for securing definitive airways in prolonged-ventilated adult patients. This might be true, but exceptions include neuroscience patients requiring prolonged cannula care. Furthermore, anesthesiologists must keep in mind that any procedure in airway management is influenced by individual experience and preference.

1 Conventional Surgical Tracheostomy

Tracheal dissection to provide relief from airway obstruction resurfaced in the diphtheria epidemic in the 19th century. The current technique for “conventional” ST was first described by Jackson¹⁹⁷ in 1909. Many variations exist in technique, but ST is preferably performed in the OR.²¹⁶ In critically ill patients for whom transport seems too risky, tracheostomy can also be performed in the ICU bed, although mainly under inferior surgical conditions. Positioning the patient with head and neck extended and a small pillow under the shoulders is a major part of successful technique. Overextension of the head should be avoided; the airway might be narrowed further, and the tracheostomy site might be erroneously too low (near innominate artery). The operating field should be prepared according to aseptic conditions. Patients who do not tolerate this position may assume a sitting or semi-recumbent position.

After proper preparation, palpate the landmarks (e.g., thyroid and sternal notch, cricoid cartilage), and make a 3-cm vertical skin incision extending inferior to the cricoid cartilage. Some advocate a horizontal incision because of the better cosmetic results. Subcutaneous fat can be resected using electrocautery, and the inferior limit of the surgical field should be screened for the proximity of the innominate artery. Dissect platysma until the midline raphae between the strap muscles are identified. Strictly adhere to the midline to avoid bleeding and paratracheal structures. After retracting the strap muscles laterally, the pretracheal fascia and the thyroid isthmus are exposed. The thyroid may be retracted out of field, but a resection is recommended due to the reduced incidence of postoperative bleeding complications. Securing the cricoid cartilage with a hook and superior traction improves control of the tracheal entry. Tracheal incision should be performed between the second and third or the third and fourth tracheal rings. The first tracheal ring should always be left intact to protect the cricoid cartilage.

Several options for a semipermanent tracheostomy exist; a T-, U-, or H-shaped tracheal opening can be made, with the tracheal flaps sutured to the neck skin. Creation of a U-shaped flap (“Björk flap”) is not recommended because of the increased risk of flap necrosis. No tracheal cartilage should be resected, to reduce the risk of tracheal stenosis.

A permanent tracheostoma is necessary for patients who indefinitely require secure transluminal access (e.g., head injury). For the creation of a permanent stoma, a small portion of the anterior tracheal wall is resected, and skin flaps are sutured to the rectangular tracheal opening (Fig. 46-12).

Figure 46-12 Permanent epithelialized tracheostoma.

(From Hartung, Osswald, Petroianu, editors: Die Atemwege. Wissenschaftliche Verlagsgesellschaft, Stuttgart, 2001, p 159.)

2 Percutaneous Dilatational Tracheostomy Techniques

During the 1990s, a dramatic change in airway management for long-term ventilatory support occurred with the introduction of percutaneous approaches to the trachea. Percutaneous tracheostomy was first described by Shelden and colleagues¹⁹⁸ in 1955, but the approach never became popular because of severe complications.¹⁹⁹ With the introduction of the Seldinger technique by Ciaglia and others,²⁰⁰ a triumphant advance of percutaneous tracheostomy began because of presumed advantages (Box 46-3).

Box 46-3 Major Advantages of Percutaneous Approach to Tracheostomy

1. Bedside procedure

2. Easy to learn

3. Reduced personnel

4. Reduced incidence of wound infection

Simpson and associates²¹⁷ showed that the number of critically ill patients at their facility undergoing tracheostomy had increased from 8.5% to 16.8% of all critically ill patients since the introduction of PDT. This represents a doubling of the proportion of ICU patients undergoing tracheostomy. Tracheostomy was also performed significantly earlier, at a median of 4 days versus 8 days of mechanical ventilation. Of approximately 31,000 tracheostomies performed in Germany (~80 million population), more than 50% were PDTs.

The question of which technique, ST or PDT, is better for tracheostomy remains to be answered definitively.

a Percutaneous dilatational tracheostomy according to Ciaglia

Pasquale Ciaglia introduced PDT in 1985 as an alternative approach to conventional ST.²⁰⁰ Using the original Ciaglia technique, the correct puncture site in the midline between first or third tracheal ring is identified, the trachea punctured (free aspiration of 20 mL air possible), and a guidewire inserted. Over this guidewire, special dilators are introduced, and the anterior wall of the trachea is dilated until an opening with a diameter of approximately 36 French is achieved (Fig. 46-13). Advantages of this method are short duration of the procedure and bedside performance. However, contraindications must be considered (Box 46-4).

Figure 46-13 PercuQuick set for percutaneous tracheostomy.

(Courtesy of Rüsch, Essilengen, Germany.)

Box 46-4 Contraindications to Percutaneous Dilatational Tracheostomy

1. Trauma or infection in region of presumed stoma, with inability to localize trachea

2. Palpable vessels at puncture site

3. Coagulation disorders (PLT <30,000/µL; PTT >50%)

4. FIO₂ >0.8

5. Known or suspected difficult airway

To enhance patient safety, Marelli and colleagues²¹⁸ proposed that the entire procedure be monitored fiberoptically. The use of a FOB prevents endotracheal insertion out of the anterior midline or injury to the posterior tracheal wall, particularly during dilatation. A drawback of FOB control is that its insertion into the airway results in a partial obstruction of the ventilatory path thereby compromising ventilation.²¹⁹

For performing PDT, the anesthetized patient is positioned with the head and neck extended. The anterior part of the neck is cleaned and draped in accordance with thyroid surgery guidelines. The FOB is then introduced through the tracheal tube in place, and the correct puncture site is identified. For this purpose, the ETT must be drawn back toward the glottic opening, and the FOB must be inside the ETT to prevent erroneous puncture of the scope (after the procedure, the scope must undergo a complete evaluation to prevent water intrusion).²²⁰

After puncturing the trachea in the midline between the first and third tracheal ring, a guidewire is inserted under fiberoptic vision (Fig. 46-14A). Puncturing must be done in the midline, in the middle between the tracheal cartilages. Puncture near a tracheal ring must be prevented because cartilage damage or fractures are associated with late complications such as tracheal stenosis (Fig. 46-14B). Thereafter, a guidance cannula is slid over the guidewire and a 1.5-cm skin incision made. The puncture site is then dilated with seven (hydrophilic) plastic dilators up to a diameter of 36 F (12 mm) (Fig. 46-14C). Lastly, the tracheal cannula (maximum ID of 9 mm) is inserted as guided by a medium-sized dilator (Fig. 46-14D). A slight resistance is often encountered during cannula insertion, which is overcome by using sufficient lubricating fluid and rotating movements during insertion. After cannula insertion, the FOB is removed from the ETT and inserted into the tracheal cannula, to verify correct placement, optimize cannula insertion depth, and remove bloody secretions from trachea and bronchi.

Figure 46-14 Percutaneous tracheostomy according to Ciaglia. See text for details.

(Courtesy of Rüsch,Vienna. Modified from Ciaglia P et al: Elective percutaneous dilatational tracheostomy: a new simple bedside procedure—preliminary report. Chest 87:715–719, 1985.)²⁰¹

b Percutaneous dilatational tracheostomy according to Griggs

In 1989, Schachner and associates²²¹ presented a single-dilatation tracheostomy forceps over a guidewire (Rapitrach; Fresenius, Runcom, Cheshire, UK), which carried a relatively high incidence of injury of the posterior tracheal wall. In 1990, Griggs and coauthors²²² developed another guidewire dilating forceps (Portex, Kent, England) with a smooth rounded tip (modified Howard-Kelly forceps with blunt edge). The procedure is characterized by a similar approach as the Ciaglia technique with transillumination (diaphanoscopy), puncturing of the trachea (18-gauge needle), guidewire insertion, and skin incision (Fig. 46-15). All neck structures are slightly dilated by one small dilator. Next, the specially designed forceps is inserted through the guidewire until the trachea is reached, and the skin and pretracheal tissues are dilated by opening the blades. The forceps is carefully advanced into the trachea under fiberoptic control, with the tip of the forceps pointing toward the carina. By pulling both branches of the forceps apart, the trachea is also dilated. According to the Ciaglia technique, the tracheal cannula chosen is then inserted by means of an adequate dilator over the guidewire.

Figure 46-15 Percutaneous tracheostomy according to Griggs.

(Courtesy of Rüsch, Vienna. Modified from Griggs WM et al: A simple percutaneous tracheostomy technique. Surg Gynecol Obstet 170:543–545, 1990.)

c Translaryngeal Tracheostomy According to Fantoni

The translaryngeal approach for tracheostomy (TLT) was introduced in 1996 by Fantoni and coworkers.^223,224 In contrast to all other percutaneous techniques, the initial puncture of the trachea is directed cranially (Fig. 46-16). After tracheal puncture, a guidewire is passed through the needle and passed toward the oropharynx alongside or inside the tracheal tube. The patient is then reintubated with the kit’s 5-mm-ID tube, and the wire is connected with the tracheal cannula. The cannula is then advanced through the pharynx into the trachea by constantly pulling on the guidewire. The pointed head is then pulled out the anterior tracheal wall and soft tissues of the neck. Next, the pointed head is cut off, and the cannula is to be rotated 180 degrees downward using a plastic obturator. Thereafter, the fiberoptic scope is inserted through the cannula to check correct positioning in the trachea.

Figure 46-16 Percutaneous tracheostomy according to Fantoni.

(Courtesy of Rüsch, Vienna.) (Modified from Fantoni A, Ripamonti D: A non-derivative, non-surgical tracheostomy: the translaryngeal method. Intensive Care Med 23:386–392, 1997.)

The major advantage of this approach is that minimal or no skin incision is necessary, minimizing the bleeding risk. Typical problems encountered with TLT are: difficulties with the intratracheal rotation of the cannula, the need for changing the ETT, and potential contamination of the tube during oropharyngeal passage.

Byhahn and coworkers²²⁵ investigated practicability and early complications of Fantoni’s TLT technique in 47 ICU patients. No severe complications (aspiration or bleeding) were observed; only oxygenation deteriorated in about one fourth of the patients. The authors concluded that TLT is a valuable alternative technique to Ciaglia’s approach, but should be performed only in patients requiring a fraction of inspired oxygen concentration (FIO₂) of less than 0.8. Westphal and associates²²⁶ compared TLT with the Ciaglia approach in a prospective study of 90 patients. Although success and complication rates were similar between the groups, problems during the procedure were far more common with the TLT technique, especially in positioning the guidewire correctly. Cantais and others²²⁷ prospectively compared forceps-dilational and translaryngeal technique in 100 adult critically ill patients. Fantoni’s translaryngeal technique took nearly twice as long as forceps-dilation (13 vs. 7 minutes, respectively). Although minor bleeding episodes were less in the Fantoni group, major complications were more common, and unsolvable technical problems were encountered in 23% of patients. Nevertheless, the authors concluded that both techniques are safe, and physicians should be able to choose their preferred technique.

d Rotating dilatational tracheostomy (PercuTwist)

The PercuTwist technique (Teleflexmedical Ruesch, Kernen, Germany) offers an alternative real single-step percutaneous tracheostomy approach (Figs. 46-17 and 46-18). Preparation, puncturing of the trachea, and guidewire insertion are performed according to the Ciaglia and Griggs techniques (Fig. 46-17, 1 and 2). After needle removal, an 8-mm to 10-mm skin incision is made (Fig. 46-17, 3), and a special hydrophilic dilation screw (suited for either 8 or 9 mm ID tracheal cannulas) is slid over the guidewire until the skin incision is reached (Fig. 46-17, 4). Using slight pressure, the dilator is turned clockwise until the first threads are advanced into the pretracheal soft tissues (Fig. 46-17, 5). The PercuTwist is then carefully advanced without pushing until the tip of the screw is fiberoptically visualized inside the trachea (Fig. 46-19). The screw is then advanced into the trachea twist by twist under gentle elevation of the anterior tracheal wall. The dilator is removed by counterclockwise rotation, and the tracheal cannula is inserted using an insertion dilator guided by the in situ guidewire (Fig. 46-17, 6 and 7).

Figure 46-17 PercuTwist. See text for details.

(Courtesy of Rüsch, Vienna.)

Figure 46-18 Performance of PercuTwist tracheostomy.

(Courtesy of Rüsch, Vienna.)

Figure 46-19 Fiberoptic control of the PercuTwist technique.

(Courtesy of Teleflexmedical Ruesch, Vienna.)

Frova and Quintel²²⁸ reported the use of the PercuTwist system in 50 consecutive ICU patients and found a 100% success rate without serious complications. Tracheal ring fractures were observed in 4 of 50 patients (8%), but no posterior tracheal wall injury. Westphal and coworkers²²⁹ studied 10 consecutive patients and reported no early complications besides minor bleeding (<20 mL) in two patients. In a prospective randomized study in 70 consecutive patients, Byhahn and associates²³⁰ compared safety and efficacy of PercuTwist and Blue Rhino tracheostomy. In the PercuTwist group, complications occurred in 12 patients, including posterior wall tears, tracheoesophageal fistula, false cannula passage, and four failures to insert the cannula, compared with seven complications in the Blue Rhino group. However, no statistically significant differences in minor and overall complications were observed between the two techniques. This major complication rate of 33% in the PercuTwist group was in vast contrast with the results of Sengupta and coauthors,²³¹ who observed about 90 patients over 20 months of routine use of PercuTwist. All procedures performed were graded as having absent or minimal bleeding, although six patients had abnormal clotting profiles. Grundling and colleagues²³² also reported no severe complications in 54 patients of a prospective observational clinical study. A rare complication of tracheostomy is tracheal ring fracture, which was also described with the PercuTwist technique.²³³

Yurtseven and others²³⁴ reported on 130 patients undergoing tracheostomy using three different techniques. The main finding was that PercuTwist (n = 45) was associated with minimal complications (two patients with longitudinal tracheal abrasion) and appears to be an easy to perform and practical alternative to standard PDT (n = 44, four longitudinal abrasions, one posterior tracheal wall injury, and one tracheal ring rupture) and the guidewire dilating forceps (GWDF) group (n = 41; two cases of longitudinal tracheal abrasions, one posterior tracheal wall injury). Furthermore, operating times using PercuTwist were significantly shorter than in the other groups (9.9 ±1.1, 6.2 ±1.4, and 5.4 ±1.2 minutes in PDT, GWDF, and PercuTwist groups, respectively).

Imperiale and associates²³⁵ reported on intracranial pressure changes during tracheostomy using PercuTwist. Use of PercuTwist did not cause secondary intracranial hypertension insult and therefore could also be considered safe in a select population of brain-injured patients.

A distinct advantage of the PercuTwist technique over all other percutaneous approaches is that the stoma remains open after removal of the screw, and immediate emergency intubation of the stoma with a small tracheal tube is possible. With all other devices, dilated stoma closes by the tissue pressure immediately after removal of the dilators.

e Ciaglia Blue Rhino

The technique of PDT has constantly been evolving. In 1998 a modification was introduced called Ciaglia Blue Rhino (Percutaneous Tracheostomy Introducer Kit, Cook Critical Care). The standard multiple dilators were replaced by a single, sharply tapered dilator shaped similar to the horn of a rhino (Fig. 46-20). The dilation process can be performed in a single step, without the need to change dilators (Fig. 46-21). Therefore, the risk of injury to the posterior tracheal wall, bleeding episodes, and impaired oxygenation by repeated airway obstruction during the dilation process may be reduced.²³⁶

Figure 46-20 Ciaglia Blue Rhino dilator set for percutaneous tracheostomy.

(Courtesy of Rüsch, Vienna.)

Figure 46-21 Single-step Ciaglia Blue Rhino: a modified technique for percutaneous dilatational tracheostomy. See text for details.

(Modified from Byhahn C et al: [Ciaglia Blue Rhino: a modified technique for percutaneous dilatation tracheostomy—technique and early clinical results]. Anaesthesist 49:202–206, 2000.)

The Percutaneous Tracheostomy Introducer Set consists of a puncture needle, guidewire, small dilator and special Blue Rhino dilator, and three curved stylets for placement of the tracheostomy tube. Instructions are as follows²³⁷:

1. Withdraw the ETT under fiberoptic control to a level above the assumed puncture site.

2. Make a horizontal skin incision and puncture the trachea in the midline between the second and third tracheal cartilage rings.

3. Introduce the guidewire using the Seldinger technique.

4. Withdraw the needle, and introduce the guiding catheter.

5. Predilate the puncture canal with the small dilator.

6. To increase the dilator’s external smoothness, moisten the Blue Rhino dilator with a few milliliters of saline solution or distilled water.

7. Advance the wet dilator over the guidewire and guiding catheter through the soft tissues and into the trachea up to its marking of 38-F external diameter. The dilation should require a minimum of force because of the dilator’s smoothness (Fig. 46-21A and B).

8. Ensure the Blue Rhino PDT set contains three hard-rubber stylets of different sizes with cone-shaped tips. The tracheostomy tube should be armed with its corresponding stylet.

9. Advance this perfectly fitting unit into the trachea (Fig. 46-21C).

10. Afterward, withdraw the stylet and confirm the correct position of the tracheostomy tube using fiberoptic bronchoscopy.

11. Connect the tube with the respirator, and remove the ETT.

In a small, prospective, randomized study in 2000, Byhahn and others²³⁷ compared the classic PDT with the Blue Rhino in 50 critically ill patients and reported a relatively high incidence of cartilage damage (9 of 25 cases), but no life-threatening complications with either method. In 2002, Fikkers and associates²³⁸ assessed perioperative, early, and late complications in 100 consecutive Blue Rhino tracheostomies. Success rate was 98%, with minor and major complications observed in 30% and 12%, respectively. Tracheal stenosis was observed in one patient (over 6-12 months). In 2003, Dongelmans and others²³⁹ showed that the use of Blue Rhino in an ICU environment is associated with a very low rate of major and minor complications.²⁴⁰ In a retrospective study of 318 tracheostomies, Bhatti and associates²⁴⁰ reported a low complication rate similar to open surgical tracheostomy, concluding that the complication rate of PDT can be reduced further with experience and use of strict protocols, making it even safer than an open ST.

In 2005, Kost and colleagues²⁴¹ evaluated 500 adults; 309 underwent PDT using Ciaglia Blue Rhino (single dilator), and 191 used the Ciaglia Percutaneous Tracheostomy Introducer Kit (multiple dilator). Total complication rate was 9.2% (6.5% in Blue Rhino and 13.6% in multidilator group). The most frequent intraoperative complications were brief oxygen desaturation (14 patients) and bleeding (12 patients). This study also identified ASA class IV patients as having a significantly increased risk of complications. Johnson²⁴² and Ambesh²⁴³ and coworkers showed that the single-dilator technique decreased operative time compared with the serial-dilator technique. In both studies, complication rates were not increased by single-step dilation. In 2007, De Leyn and colleagues²⁴⁴ performed a systematic review and recommended the modified Blue Rhino as the technique of choice, based on its simplicity and short procedure time (level 2c). In 2010, Dempsey and colleagues²⁴⁵ reported a prospective evaluation of the single-tapered-dilator technique, with tracheostomies performed in 589 patients (2003-2009). PDT was attempted in 576 patients and successfully completed in 572. Four attempts were stopped due to bleeding. In 149 patients (26%) intraoperative technical difficulties were encountered. Early complications occurred in 16 patients (3%). Significant late complications occurred in four patients; in two patients, a trachea-innominate fistula was found and led to the death of both patients. The mortality directly attributable to PDT was 0.35%.

Based on clinical studies and personal experience, the single-step PDT currently is the most widely used technique.^245–248

f Ciaglia Blue Dolphin

In 2009, Gromann and associates^249,250 studied a modified PDT called Blue Dolphin, a balloon dilation technique that exerts mainly radial force to widen the tracheostoma. This force may reduce complications such as fracture of tracheal cartilage rings or injuries to the posterior tracheal wall (Fig. 46-22).

Figure 46-22 Ciaglia Blue Dolphin set balloon percutaneous tracheostomy introducer: a, introducer needle; b, wire guide; c, 14-F dilators; d, balloon-tipped catheter loading dilator assembly; e, Cook inflation device.

(From Gromann TW et al: Balloon dilatational tracheostomy: initial experience with the Ciaglia Blue Dolphin method. Anesth Analg 108:1862–1866, 2009.)

Surgical Procedure

1. Ensure optimal placement of patient with full extension of head and neck.

2. Perform surgical disinfection and sterile covering of the operative area.

3. Manually examine the cricoid cartilage.

4. Make a 1-cm to 2-cm, horizontal surgical incision.

5. Puncture the trachea at the level between the second and third tracheal cartilages.

6. Ensure puncture of the trachea using bronchoscopy.

7. Place the guidewire using the Seldinger technique.

8. Enlarge the puncture canal with the blue, short introducing dilators.

9. Attach the prepared inflation device to the balloon port on the balloon-catheter assembly.

10. Remove the introducing dilators; the guidewire remains in situ.

11. Introduce the prepared tracheostomy tube.

a. Fill up the balloon with normal saline using the inflation pump (max pressure, 11 atm).

b. Hold this pressure for at least 15 seconds.

c. Deflate the balloon.

d. Simultaneously insert the balloon-catheter assembly, loading dilator, tracheostomy tube, and guidewire.

e. When tracheostomy tube is in place, remove the rest of the assembly.

f. Inflate the tracheal tube–balloon cuff.

g. Verify by bronchoscopy.

In the primary study by Gromann,²⁵⁰ 20 patients underwent this procedure at the ICU bedside, and surgery averaged 3.3 ±1.9 minutes. There were no injuries of the posterior tracheal wall, no bleeding requiring treatment, or wound infections. One patient had a fracture of a tracheal ring, and another patient had subcutaneous emphysema.

In 2010, Cianchi and others²⁵¹ compared this new Blue Dolphin system with the Ciaglia Blue Rhino system in 70 ICU patients. Surgical procedure time in the Blue Rhino group was significantly shorter than in the Blue Dolphin group (1.5 vs. 4 minutes). Limited intratracheal bleeding requiring no intervention was more frequent in the Dolphin group. Although Blue Rhino was associated with fewer tracheal injuries and time for procedure was shorter, the authors concluded that PDT using the Ciaglia Blue Dolphin technique is a feasible and viable option in ICU patients.

D Airway Management During Tracheostomy

During puncture of the trachea, the endotracheal tube must be withdrawn just below the vocal cords to protect the bronchoscope and tube cuff. Therefore, alternative approaches such as ventilatory support using a laryngeal mask airway or a Fastrach have been suggested.^252–254 In an RCT, Dosemeci and colleagues²⁵⁵ studied LMA as an alternative airway for management during PDT in 60 patients, concluding that LMA is an effective and successful ventilatory device. It improves visualization of the trachea and larynx during fiberoptic-assisted PDT and prevents the difficulties associated with use of the ETT, such as cuff puncture, tube transection by the needle, and accidental extubation. However, Ambesh and associates²⁵⁶ clearly demonstrated that changing ETT to LMA might result in potentially life-threatening complications, including loss of the airway during PDT. In a prospective randomized study, they compared the safety and efficacy of ETT versus LMA ventilation during PDT in 60 critically ill patients. Although the complication rate was low in the ETT group (7% ETT impalement, 7% cuff puncture, and 3% accidental extubation), a high rate of complications was observed in the LMA group (33% incidence of airway loss, inadequate ventilation, and gastric distention). A change of the ETT for an LMA during the performance of tracheostomy therefore cannot be recommended and may only be an alternative method for patients not intubated before the procedure.

E Perioperative and Early Complications of Tracheostomy

A number of potential complications may occur during or immediately after PDT (Box 46-5). Bleeding is the most common perioperative complication, with incidence up to 4%.²⁵⁷ After controversial statements, routine chest radiography for identifying complications at an early stage is not longer recommended after tracheostomy placement, unless there are signs of unexpected compromise of air exchange.^258,259 Ambesh and associates²⁴³ compared two percutaneous single-dilator techniques (Blue Rhino, Griggs dilating forceps) in 60 consecutive patients. Percutaneous access to the trachea was possible in all patients, with significantly more difficult cannulations in the Griggs group (30% vs. 7%). Overdilatation of the stoma occurred more frequently in the Griggs group (23% vs. 0%), whereas Blue Rhino was often associated with tracheal ring fractures (30% vs. 0%). Some variation in complications is seen with different techniques for PDT. The single-dilator technique (Blue Rhino) appears to be fast and incurs no more risk than the multiple-dilator technique of Ciaglia.^238,242

F Late Complications of Tracheostomy

Many mechanisms may cause late complications after tracheostomy.⁴⁶ The most important factors may be placement of the tube, especially prolonged intubations; leaving the tube in place for prolonged periods, possibly related to inflated cuff; and abnormal healing at the site of injured tracheal mucosa. Clinically relevant late complications after tracheostomy occur in up to 65% of patients.^260–263 The most common and important complication is development of granulation tissue. Granulation tissue occurs subclinically or presents as failure to wean patients from ventilator, failure to decannulate, or as upper airway obstruction with respiratory failure after decannulation.²⁶⁴ Further late complications include tracheal stenosis, aspiration pneumonia, tracheomalacia, and tracheoesophageal fistula²⁶⁵ (Table 46-10).

After its introduction by Ciaglia in 1985,²⁰⁰ many investigators have reported their experience with the technique and have concluded that PDT is safe and cost-effective. Vigliaroli and others²⁶⁶ reported their clinical experience with Ciaglia’s dilational tracheostomy over 6 years in 304 patients, 41 of whom were evaluated for late complications. No perioperative death occurred, and early complication rate was 5%. No late complications (e.g., tracheal stenosis) were observed in any of the fiberoptically investigated patients during follow-up to 180 days.

Escarment and associates²⁶⁷ evaluated the safety and complication rates of the Griggs technique in a consecutive series of 162 ICU patients. Early intraoperative complications occurred in 17%, being minor technical difficulties without morbidity (e.g., inadvertent extubation, difficult cannulation, hemorrhage). Average cannulation duration was 25 days, and stoma closure was effective in all patients after about 3 to 4 days. Follow-up was available in 81 patients, and endoscopic evaluation of the airways 3 months after decannulation was performed in 73 patients; 62 (85%) were normal, seven (10%) had granulation tissue at the stoma site, and four (5%) had tracheal stenosis, with dyspnea in two patients (3%).

Norwood and colleagues²⁶⁸ determined the incidence of tracheal stenosis and other late complications after PDT in 422 patients undergoing tracheostomy between 1992 and 1999 (Ciaglia approach). Of the 340 survivors, 100 were interviewed and further evaluated by fiberoptic laryngotracheoscopy and tracheal computed tomography. CT scans identified mild stenosis (11%-25%) in 21% of patients (all asymptomatic), moderate stenosis (26%-50%) in 8%, and severe stenosis (>50%) in 2% of patients (Fig. 46-23; see also Fig. 46-11A).

Figure 46-23 Patient with 45% tracheal stenosis. A, Axial view of normal trachea just above stoma level. B, Axial view of stoma level; arrows denote areas of anterior and lateral stenosis. C, Coronal view with circled area of stenosis; dotted arrow denotes false vocal cords; solid arrow indicates true vocal cords. D, Sagittal view with circled area of stenosis.

(From Norwood S et al: Incidence of tracheal stenosis and other late complications after percutaneous tracheostomy. Ann Surg 232:233–241, 2000.)

Hotchkiss and coworkers²⁶⁹ performed a cadaver study to evaluate the stoma and surrounding insertion site for laryngotracheal injury in six fixed cadaver specimens. Puncture and dilation were performed using the Blue Rhino technique, and no fiberoptic control of the procedure was used. Puncture level was accurately predicted in only 50% of cadavers. Anterior tracheal internal wall mucosal injury was observed in all specimens. Cartilaginous injury was severe in five of six specimens that sustained multiple comminuted injuries to two or more adjacent tracheal rings. The authors concluded that the injuries observed may significantly contribute to the development of tracheal stenosis. However, no data are presented on the potential impact of bronchoscopic guidance on the incidence of these complications.

Leonard and others²⁷⁰ assessed the late outcome following forceps tracheostomy in a prospective observational study of 49 patients. Tracheal stenosis was observed in one patient (2%), whereas other, minor complications (e.g., change in voice, 49%) were observed frequently. However, whether this was caused by the preceding translaryngeal intubation or the technique of tracheostomy could not be determined.

The main problem of PDT leading to tracheal stenosis is that tracheal rings are forced into a position that creates the opening for the cannula. This maneuver is capable of deforming the tracheal cartilage so that it protrudes into the airway (Fig. 46-24).

Figure 46-24 Suprastomal stenosis. Anterior tracheal wall is invaginated into the lumen.

(From Koitschev A, et al: Tracheal stenosis and obliteration above the tracheostoma after percutaneous dilational tracheostomy. Crit Care Med 31:1574–1576, 2003.)

Koitschev and associates²⁷¹ reported on three patients with severe tracheal stenosis/obliteration after PDT (Figs. 46-25 and 46-26). In all patients, tracheal narrowing occurred above the level of the stoma. The authors speculated the cause was a procedure-related mechanism (tracheal ring invagination and consecutive development of granulation tissue) rather than a mechanism based on the duration of cannulation (normally producing stenosis below the stoma).

Figure 46-25 Endotracheal view revealing invagination of the cartilage rings.

(From Koitschev A, et al: Tracheal stenosis and obliteration above the tracheostoma after percutaneous dilational tracheostomy. Crit Care Med 31:1574–1576, 2003.)

Figure 46-26 Anatomic specimen of resected trachea: front (A) and back (B) views. Arrows indicate scar tissue above the stoma.

(From Koitschev A, et al: Tracheal stenosis and obliteration above the tracheostoma after percutaneous dilational tracheostomy. Crit Care Med 31:1574–1576, 2003.)

In conclusion, PDT seems to be a safe, relatively simple, and quick procedure that can performed at bedside. Early complications and infection rate (~2%) might be even lower and cosmetic results better than with surgical tracheostomy. However, PDT must be performed by an experienced operator at the correct puncture site, straight in the midline between two tracheal rings, and may never be performed without fiberoptic guidance.²⁷² All special techniques proposed are characterized by special drawbacks or complications. The Blue Rhino technique is associated with a relatively high incidence of tracheal ring fractures (~30%), whereas the PercuTwist approach has a higher risk of posterior tracheal wall injury. It is therefore difficult to compare “percutaneous dilatational tracheostomy” to the conventional surgical approach, since these are completely different techniques with different success and complication rates. Much larger studies over a longer time studying clearly defined patients and techniques are necessary to clarify the incidence of late complications after PDT. Currently, it is too early to draw definitive conclusions on PDT versus surgical tracheostomy.

G Conventional (Surgical) vs. Percutaneous Tracheostomy

Comparing PDT with historical data of complications of ST is erroneous and may give a biased picture. Moreover, varying definitions and different techniques used by the authors make interpretation of data difficult. Complication rates for ST vary widely, between 6% and 66%, with mortality of 2%.²⁷³ To reduce this incidence of complications and to perform a bedside procedure, the different percutaneous techniques have been proposed.

Special reference to early complications shows that serious bleeding can occur with either ST or PDT, but appears to be less frequent with PDT.²⁷⁴ Considerable danger arises in the significant rate of posterior tracheal wall perforation with development of tension pneumothoraces when using PDT.²⁷⁵ To avoid posterior tracheal wall injury, guidewire and guiding catheter should be firmly stabilized during PDT, and fiberoptic visualization of the entire process is obligatory. In common, pneumothorax is infrequent when using PDT but occurs in 1% to 3% when using ST.²⁷⁶

Numerous studies suggest minimal difference in acute serious complications between ST and PDT,²⁷⁷ while others propose a learning curve and a significantly lower complications rate thereafter. Petros²⁵⁷ clearly showed a learning curve in performing tracheostomy after prospectively evaluating 234 PDTs (Fig. 46-27).

Figure 46-27 Learning curve for perioperative complications during percutaneous dilatational tracheostomy.

(From Petros S: Percutaneous tracheostomy. Crit Care 3:R5–R10, 1999.)

Massick and colleagues²⁷⁸ performed a prospective analysis of complication incidence for the first 100 PDTs (Ciaglia) performed in a local community hospital. The authors clearly demonstrated a learning curve, with the first 20 patients exhibiting a significantly higher incidence of perioperative as well as late complications. Furthermore, patients with suboptimal anatomy were found to have significantly increased complication rates independent of operator and institutional experience. PDT has a steep learning curve, with most perioperative, postoperative, and late complications occurring in the first 20 patients.

Beiderlinden and others²⁷⁹ assessed the incidence of early complications of fiberoptically guided PDT beyond the learning curve (all investigators performed >100 PDTs). With 133 consecutive patients undergoing PDT (114 conventional Ciaglia technique and 22 Blue Rhino), tubes were fixed at the skin, and no routine tube exchanges were performed. Insertion of the tracheal tube was easy or modestly difficult in 87%, and no procedure-related deaths occurred. The incidence of tube-related complications (e.g., tracheal wall lesion, bleeding, cannula misplacement) was low, 0.7%. Fracture of tracheal rings was observed in 24%. Despite this finding, the authors concluded that with experience in performing PDT, fixation of the tracheal cannula, and omission of routine tube changes, the complication rate is low.

Several studies compared ST and PDT technique, in addition to multiple reviews and four meta-analyses.^{265,280–282} At present, no consensus exists as the optimal approach in terms of minimizing complications.

Dulguerov and associates²⁸⁰ performed a meta-analysis comparing surgical and percutaneous access to the trachea. Study patients were grouped as having surgical tracheostomy from 1960 to 1984 (17 investigations in 4185 patients), surgical tracheostomy from 1985 to 1996 (21 studies in 3512 patients), or PDT (27 studies in 1817 patients). The highest perioperative and postoperative complication rates were observed in the “older” surgical studies (9% and 33%, respectively). Although perioperative complication rates were higher in the percutaneous studies (10% vs. 3%), postoperative complications were lower compared with the surgical approach (7% vs. 10%). However, this meta-analysis was criticized because studies on percutaneous tracheostomy without fiberoptic control were also included. Furthermore, it is difficult to perform a meta-analysis on this topic because not only percutaneous versus surgical approaches were compared. The percutaneous group is a mix of several different procedures and techniques used (i.e., with or without fiberoptic control, Ciaglia or Griggs technique).

Subsequently, Delaney and coauthors²⁶⁵ performed a systematic review and meta-analysis, including 17 RCTs involving 1212 patients. Pooled analysis showed no statistical difference in mortality or major complications. The rate of wound and stoma infections was low, 6.6%, but infections were significantly less common in the PDT group. Unfortunately, studies rarely include long-term follow-up, and significant late complications may be missed.

In a meta-analysis, Freeman and associates²⁸¹ examined five studies (236 patients) and found that PDT was associated with a lower overall postoperative complication rate, less perioperative bleeding, and lower incidence of stomal bleeding and stomal infection. In addition, PDT was quicker than ST by 9.84 minutes. The meta-analysis of Higgins and Punthakee²⁸² included 973 patients from 15 RCTs (490 PDTs and 483 STs). The author found significantly fewer complications in PDT with respect to wound infection and unfavorable scarring. Consequently, overall complications trended toward favoring the percutaneous technique. PDT appeared to be more cost-effective by freeing up OR resources, including time and personnel; providing greater feasibility in terms of bedside capability; and allowing nonsurgeons to perform the procedure safely^282,283 (Tables 46-11 and 46-12). Most authors reported lower complication rates with the individual percutaneous technique used^272,284 (Table 46-11). Tracheostomy is increasingly performed outside the OR and by PDT rather than ST technique.²⁸⁵

TABLE 46-11 Comparison of Overall Complications for Open vs. Percutaneous Tracheostomy, Including Adjusted Values for Minor Hemorrhage

From Higgins KM, Punthakee X: Meta-analysis comparison of open versus percutaneous tracheostomy. Laryngoscope 117:447–454, 2007.

OR, Odds ratio; CI, confidence interval.

Bowen and colleagues²⁸⁶ performed a retrospective medical chart review. Over 23 months, 213 patients received ST (n = 74) or PDT (n = 139). Perioperative complications occurred in five of 74 patients (6.76%) during PDT (whereas three patients, 4.1%, required emergent operative exploration of the neck) versus three of 139 patients (2.2%) during ST. Surgical time for PDT in the ICU was significantly shorter and cost less than ST performed in the OR.

In conclusion, all studies clearly show that adequate training and teaching is the major factor reducing complications with PDT. Until those issues are cleared, PDT can be recommended with some exceptions. Especially in patients presenting with a short thick neck, goiter, or difficult airway, PDT should be performed only by an experienced physician, with a physician prepared for ST present.²⁸⁷ The most important part is fiberoptic control of the entire procedure, since erroneous punctures or direct trauma of the esophagus or tracheal wall are prevented or recognized early.²⁸⁸