Chapter 70 Anesthesia, Perioperative Care, and Sedation
The primary purpose of general anesthesia is to suppress the conscious perception of, and physiologic response to, noxious stimuli and to render the patient unconscious. Potent drugs are used to blunt physiologic responses to what would otherwise be life-threatening trauma (surgery). Intraoperatively, the anesthesiologist is responsible for providing analgesia as well as physiologic and metabolic stability (see Table 70-1 on the Nelson Textbook of Pediatrics website at 
www.expertconsult.com). This responsibility is facilitated by obtaining an adequate preanesthesia history (see Table 70-2 on the Nelson Textbook of Pediatrics website at 
www.expertconsult.com). The increased risk of morbidity and mortality in the perioperative period demands the utmost vigilance. The risk is even higher in certain disease states (see Table 70-3 on the Nelson Textbook of Pediatrics website at 
www.expertconsult.com).
Table 70-2 THE PREANESTHETIC HISTORY
Child’s previous anesthetic and surgical procedures:
Perinatal problems (especially for infants):
Other major illnesses and hospitalizations
Family history of anesthetic complications, malignant hyperthermia, or pseudocholinesterase deficiency
Respiratory problems:
Cardiac problems:
Gastrointestinal problems:
Exposure to exanthems or potentially infectious pathogens
Neurologic problems:
Hematologic problems:
Renal problems:
Psychosocial considerations:
Gynecologic considerations:
Current medications:
Allergies:
Dental condition (loose or cracked teeth)
When and what the child last ate (especially in emergency procedures)
Table 70-3 SPECIFIC PEDIATRIC DISEASES AND THEIR ANESTHETIC IMPLICATIONS
| DISEASE | IMPLICATIONS |
|---|---|
| RESPIRATORY SYSTEM | |
| Asthma | Intraoperative bronchospasm that may be severe |
| Pneumothorax or atelectasis | |
| Optimal preoperative medical management is essential; preoperative steroids may be required | |
| Difficult airway | Special equipment and personnel may be required |
| Should be anticipated in children with dysmorphic features or acute airway obstruction, as in epiglottitis or laryngotracheobronchitis or with an airway foreign body | |
| Patients with Down syndrome may require evaluation of the atlanto-occipital joint | |
| Patients with storage diseases may be at high risk | |
| Bronchopulmonary dysplasia | Barotrauma with positive pressure ventilation |
| Oxygen toxicity, pneumothorax a risk | |
| Cystic fibrosis | Airway reactivity, bronchorrhea |
| Risk of pneumothorax, pulmonary hemorrhage | |
| Atelectasis | |
| Patient should be assessed for cor pulmonale | |
| Sleep apnea | Pulmonary hypertension and cor pulmonale must be excluded |
| Careful postoperative observation for obstruction required | |
| CARDIAC | |
| Need for antibiotic prophylaxis for bacterial endocarditis | |
| Use of air filters; careful purging of air from the intravenous equipment | |
| Physician must understand the effects of various anesthetics on the hemodynamics of specific lesions | |
| Preload optimization and avoidance of hyperviscous states in cyanotic patients | |
| Possible need for preoperative evaluation of myocardial function and pulmonary vascular resistance | |
| Provide information about pacemaker function and ventricular device function | |
| HEMATOLOGIC | |
| Sickle cell disease | Possible need for simple or exchange transfusion based on preoperative hemoglobin concentration and percentage of hemoglobin S |
| Importance of avoiding acidosis, hypoxemia, hypothermia, dehydration, and hyperviscosity states | |
| Oncology | Pulmonary evaluation of patients who have received bleomycin, bis-chloroethyl-nitrosourea, chloroethyl-cyclohexyl-nitrosourea, methotrexate, or radiation to the chest |
| Avoidance of high oxygen concentration | |
| Cardiac evaluation of patients who have received anthracyclines; risk of severe myocardial depression with volatile agents | |
| Potential for coagulopathy | |
| RHEUMATOLOGIC | |
| Limited mobility of the temporomandibular joint, cervical spine, arytenoid cartilages | |
| Careful preoperative evaluation required | |
| Possible difficult airway | |
| GASTROINTESTINAL | |
| Esophageal, gastric | Potential for reflux and aspiration |
| Liver | High overall morbidity and mortality in patients with hepatic dysfunction |
| Altered metabolism of some drugs | |
| Potential for coagulopathy | |
| Renal | |
| Altered electrolyte and acid-base status | |
| Altered clearance of some drugs | |
| Need for preoperative dialysis in selected cases | |
| Succinylcholine to be used with extreme caution and only when the serum potassium level has recently been shown to be normal | |
| NEUROLOGIC | |
| Seizure disorder | Avoidance of anesthetics that may lower the threshold |
| Optimal control ascertained preoperatively | |
| Preoperative serum anticonvulsant measurements | |
| Increased intracranial pressure | Avoidance of agents that increase cerebral blood flow |
| Avoidance of hypercarbia | |
| Neuromuscular disease | Avoidance of depolarizing relaxants; at risk for hyperkalemia |
| Patient may be at risk for malignant hyperthermia | |
| Developmental delay | Patient may be uncooperative at induction |
| Psychiatric | Monoamine oxidase inhibitor (or cocaine) may interact with meperidine, resulting in hyperthermia and seizures |
| Selective serotonin reuptake inhibitors may induce or inhibit various hepatic enzymes that may alter anesthetic drug clearance | |
| Illicit drugs may have adverse effects on cardiorespiratory homeostasis and may potentiate the action of anesthetics | |
| ENDOCRINE | |
| Diabetes | Greatest risk is unrecognized intraoperative hypoglycemia; if insulin is administered, intraoperative blood glucose level monitoring needed ; glucose and insulin must be provided, with adjustment for fasting condition and surgical stress |
| SKIN | |
| Burns | Difficult airway |
| Risk of rhabdomyolysis and hyperkalemia from succinylcholine | |
| Fluid shifts | |
| Bleeding | |
| Coagulopathy | |
| IMMUNOLOGIC | |
| Retroviral drugs may inhibit benzodiazepine clearance | |
| Immunodeficiency requires careful infection control practices | |
| Cytomegalovirus-negative blood products, irradiation, or leukofiltration may be required | |
| METABOLIC | |
| Careful assessment of glucose homeostasis in infants | |
General Anesthesia
Analgesia
Providing analgesia for procedures both in and out of the operating room is a major responsibility and functions within a spectrum of care (Table 70-4). Techniques exist to provide profound pain relief during operative procedures for all patients, including the most critically ill infants. Blunting the physiologic responses to painful stimuli inhibits the stress response and its multiple deleterious physiologic and metabolic consequences. The response to painful and stressful stimuli is a potent stimulus of the systemic inflammatory response syndrome (SIRS), which leads to increased catabolism, physiologic instability, and increased mortality (Chapter 64). Appropriate use of medication, such as fentanyl anesthesia in neonates, reduces the incidence of postoperative bradycardia, hypotension, acidosis, interventricular hemorrhage, coagulation abnormalities, hypoglycemia, and death.
Table 70-4 DEFINITIONS OF ANESTHESIA CARE
MONITORED ANESTHESIA CARE
LIGHT SEDATION
Administration of anxiolysis and/or analgesia that obtunds consciousness but does not obtund normal protective reflexes (cough, gag, swallow, hemodynamic reflexes).
DEEP SEDATION
Sedation that obtunds consciousness and normal protective reflexes or possesses a significant risk of blunting normal protective reflexes (cough, gag, swallow, hemodynamic reflexes).
GENERAL ANESTHESIA
Administration of hypnosis, sedation, and analgesia that results in the loss of normal protective reflexes.
REGIONAL ANESTHESIA
LOCAL ANESTHESIA
NO ANESTHESIOLOGIST
An anesthesiologist will not be involved in the care of the child in any way.
Hypnosis and Amnesia
The blunting of both consciousness (hypnosis) and conscious recall (amnesia) is a crucial feature of pediatric anesthesia care. Awareness of painful, anxiety-provoking, and stressful conditions for children is just as deleterious, physically and psychologically, as the painful procedures themselves. Management is aimed at blunting the fear and emotional response during surgery, painful procedures (bone marrow aspiration, lumbar punctures), or nonpainful but anxiety-provoking procedures (MRI, CT). Many drugs provide anxiolysis, blunting of recall, and amnesia for such events (Table 70-5). Obtundation of consciousness may accompany the provision of analgesia. Hypnotic and sedative agents can induce altered consciousness without producing any analgesia; analgesia and obtunded consciousness are not synonymous. It is also possible to provide analgesia (local, spinal, or epidural analgesia) without obtunding consciousness.
| DRUG | USES AND IMPLICATIONS |
|---|---|
| MUSCLE RELAXANTS | |
| Succinylcholine | Used to facilitate endotracheal intubation and maintain muscle relaxation in emergency situations; now virtually never given routinely |
| A depolarizing neuromuscular blocking agent with rapid onset and offset properties | |
| Associated with the development of malignant hyperthermia in susceptible patients | |
| Degraded by plasma cholinesterase, which may be deficient in some individuals; such a deficiency may result in prolonged effect | |
| Fasciculations may be associated with immediate increases in intracranial and intraocular pressures as well as postoperative muscle pain | |
| Pancuronium, vecuronium, cis-atracurium, D-tubocurarine (curare) | Nondepolarizing neuromuscular blockers |
| Have less rapid onset than succinylcholine butare longer-acting | |
| Pancuronium is vagolytic, so may be of benefit in newborns, who have high levels of vagal tone; rarely used | |
| Vecuronium and rocuronium are metabolized by the liver and excreted in bile; the most commonly used | |
| Cis-atracurium is metabolized by plasma cholinesterase and therefore may be of benefit in patients with hepatic or renal disease | |
| Curare releases histamine and is long-acting | |
| HYPNOTICS | |
| Propofol | Rapidly acting hypnotic; amnestic, but not analgesic |
| Like pentothal, may cause hypotension | |
| Causes respiratory depression | |
| May increase the seizure threshold | |
| Great utility in titrated doses for sedation and with local anesthetic and short-acting opioid for outpatient procedures | |
| May suppress nausea | |
| Associated with the often fatal propofol infusion syndrome when used in prolonged intravenous infusion (>24 hr) and therefore not used for ICU sedation in children | |
| Etomidat | Cardiovascular stability on induction with no increase in intracranial pressure |
| Inhibits corticosteroid synthesis and increases ICU mortality | |
| Associated with myoclonus, potential difficulty with assisted ventilation, and pain on injection | |
| Ketamine | Hypnotic analgesic and amnestic |
| Causes sialorrhea and should be coadministered with an antisialagogue, such as atropine or glycopyrrolate | |
| May be associated with laryngospasm | |
| Causes endogenous catecholamine release, tachycardia, and bronchodilation | |
| Increases intracranial and intraocular pressures | |
| Decreases the seizure threshold | |
| Thiopental | Used to induce a state of unconsciousness; rarely used |
| Rapidly acting hypnotic, but not an analgesic | |
| Offset is by redistribution, not by metabolism | |
| May cause hypotension because of its myocardial depressant effects and by vasodilation | |
| Causes respiratory depression | |
| Releases histamine and may be associated with bronchospasm in susceptible individuals | |
| Increases the seizure threshold | |
| SEDATIVE-ANXIOLYTICS | |
| Benzodiazepines | May produce sedation, anxiolysis, or hypnosis, depending on the dose |
| May produce antegrade but not retrograde amnesia | |
| All agents raise the seizure threshold, are metabolized by the liver, and depress respiration, especially when administered with opioids | |
| Frequently administered as premedications | |
| Diazepam may be painful on injection and has active metabolites | |
| Midazolam can be administered by various routes and has a short half-life | |
| Lorazepam has no active metabolites | |
| Sedation effected by all benzodiazepines may be reversed by flumazenil, but respiratory depression may not be reliably reversed | |
| Dexmedetomidine | Produces anxiolysis, sedation, sympatholysis, by α2-receptor stimulation centrally; has mild analgesic properties |
| Side effects include hypotension and bradycardia | |
| Increasingly used for procedural sedation | |
| Continuous infusion for ICU sedation; currently limited to 24 hr | |
| ANALGESIC-SEDATIVES | |
| Opioids | Gold standard for providing analgesia |
| May cause respiratory depression | |
| Morphine and, to a lesser extent, hydromorphone may cause histamine release | |
| The synthetic opioids fentanyl, sufentanil, and short-acting alfentanil may have a greater propensity to cause chest wall rigidity when administered rapidly or in high doses and are also associated with the rapid development of tolerance; these 3 drugs have particular utility in cardiac surgery because of the hemodynamic stability associated with their use | |
| Remifentanil is an ultra–short-acting synthetic opioid that is metabolized by plasma cholinesterase; it may have particular utility when deep sedation and analgesia are required along with the ability to assess neurologic status intermittently | |
| INHALATIONAL AGENTS | |
| Nitrous oxide | Causes amnesia and mild analgesia at low concentrations |
| Danger of hypoxic mixture if the oxygen concentration is not monitored and preventive safety mechanisms are not in place | |
| Potent vapors | “Complete anesthetics”—they induce a state of hypnosis, analgesia, and amnesia |
| All are myocardial depressants, and some are vasodilators | |
| May trigger malignant hyperthermia in susceptible individuals | |
| Isoflurane and enflurane are fluorinated ethers and isomers | |
| Enflurane may lower the seizure threshold—rarely used | |
| Halothane has been the gold standard for performing inhalation induction of anesthesia in children, but sevoflurane, a newer drug, is also well tolerated and has more rapid kinetics (onset and offset) because of its low solubility in blood. No longer available in the USA. | |
| Sevoflurane is almost universally used for inhalation induction of anesthesia in children. | |
| All are bronchodilators at equipotent concentrations | |
| Isoflurane, enflurane, and especially desflurane are associated with a higher incidence of laryngospasm, when used for anesthetic induction, than sevoflurane | |
ICU, intensive care unit.
Sedation describes a medically induced state that is on a continuum between the fully alert, awakened state and general anesthesia (see Table 70-4). In addition to inducing unconsciousness and amnesia, general anesthesia obtunds or ablates critical physiologic reflexes; the most important are airway-protective reflexes: coughing, gagging, and swallowing. Cardiorespiratory reflexes are also obtunded with general anesthesia; respiratory depression and hemodynamic compromise may occur and may be profound. As sedation deepens toward general anesthesia, loss of airway patency, loss of airway-protective reflexes, and loss of cardiovascular stability occur. Light (minimal) sedation is anxiolysis without loss of these reflexes or airway patency. Deep sedation occurs when these reflexes are obtunded or lost (see Table 70-4). Adequate sedation in children may be accompanied by the actual or potential loss of vital reflexes. It is mandatory that those providing sedation for a child be able to detect the transition into deep sedation and general anesthesia and be prepared to manage the child’s airway and circulation, and provide cardiopulmonary resuscitation (CPR) if required.
Akinesia (Immobility or Muscular Relaxation)
Akinesia is the absence of movement. It is necessary to ensure safe and adequate operative conditions and to provide ideal conditions for advanced and meticulous surgery. Akinesia is produced with muscle relaxants (see Table 70-5). These agents facilitate respiratory management in the perioperative period and in critically ill patients. The absence of movement is neither the absence of pain nor the presence of amnesia. Whenever neuromuscular blocking agents are used, analgesia and sedation must be provided.
Physiologic Support
The need for anesthesia increases the need to monitor and support physiologic integrity and homeostasis. Sedation and anesthesia have significant and potentially life-threatening physiologic consequences (see Tables 70-4 and 70-5). Maintenance of adequate cardiorespiratory function, fluid management, electrolyte control, thermoregulation, and concern for all aspects of the child’s health are critical during anesthesia.
Vigilance
Constant, critical attention by physicians who understand the demands of the surgical procedure as well as the changes in physiologic status and their implications is mandatory to provide safe perioperative care for all children. Careful attention to a child’s preoperative condition is mandatory for minimizing the risk during perioperative care (see Tables 70-3 and 70-4).
