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Complications of ambulatory anesthesia in pediatric populations are similar in many ways to those that may be encountered in adults. Higher incidences of adverse events are reported for children with higher ASA classifications, and children less than one month old and less than one year old are particularly prone to anesthesia‐related complications [22]. For pediatric and adult patients, much of the risk of complications from anesthesia can be attributed to underlying disease states and surgical risk factors. Nonetheless, there is an additional element of risk in the pediatric population due to decreased physiological reserve.

Children, far from being miniature adults, are different in fundamental anatomical and physiological ways. The immature cardiac, hepatic, renal, and respiratory systems in the child mean that large differences in drug effects, drug metabolism, and cardiac and respiratory compensations exist. Some of these differences are predictable, whereas others are not. In general, the interpatient variability in the pediatric patient can be far greater than that in an adult, necessitating more caution in the provision of anesthesia and complicating the titration of common anesthetic drugs.

Since children are smaller and weigh less than adults, the total doses of anesthetic drugs that may be safely given will be less. Due to the immaturity of the hepatic liver enzymes at birth, infants do not metabolize drugs as effectively as adults, and the clearance of many drugs can be prolonged significantly, with most individuals attaining full liver microsomal function at about one year of age [16]. Other physiological systems take longer to reach maturity, particularly the cardiovascular and respiratory systems.

The pediatric airway is characterized by a more cephalad position of the larynx, a thicker epiglottis, and angulation of the true vocal folds, which can make direct visualization more challenging (see Figure 1.1) [20]. In addition, the narrowest part of the pediatric airway occurs at the level of the cricoid cartilages just below the vocal folds; in contrast, the narrowest portion of the adult airway is typically the glottis itself. The chest wall and upper airway of the infant and young child are more compliant such that collapse of the airway occurs more easily and leads to airway obstruction [20]. Not only are children more prone to airway obstruction, but their increased oxygen and metabolic demand makes them more sensitive to hypoxia. Respiratory arrest can quickly lead to cardiac arrest if not promptly addressed.

Fig. 1.1. Compared to an adult airway, the pediatric airway demonstrates more cephalad position of the vocal folds, a wider and angled epiglottis, a relatively larger tongue and lymphoid tissue (including lingual tonsil), and a narrower funnel‐shaped cricoid cartilage.

The pediatric cardiovascular system is different from that of adults as well. In children, cardiac output is maintained primarily through heart rate rather than systemic vascular resistance. A sudden or sustained decrease in heart rate can precipitate a severe drop in blood pressure and cardiac output in a child due to the relative lack of compensation via increase in peripheral vascular resistance. In practice, this means that most cardiac arrests in children are preceded by bradycardia.

Children also have an increased body surface area relative to their mass and are more susceptible than adults to hypothermia and insensible fluid losses. They may be more prone to hypoglycemia and dehydration and less able to tolerate prolonged preoperative fasting.

Children are frequently less able to communicate effectively, less cooperative, and more prone to anxiety and emotional outbursts. The increased emotional lability of some children can make these patients challenging to manage preoperatively and can complicate and prolong the postoperative recovery period. The age and anticipated level of cooperation of a given child patient often dictate the anesthetic plan, with pediatric patients sometimes requiring oral premedication prior to the planned procedure.

The range of complications that can occur in pediatric patients during ambulatory anesthesia is the same as for adults, though not all complications occur with similar frequency. In children, respiratory complications are among the most frequently reported serious adverse effects. The overall rate of adverse events is higher in children than in adults, ranging from 1.45% to as high as 6% in different studies [15, 23, 24].