Anesthetic Management

All children should be monitored with standard monitoring that includes a pulse oximeter, a capnograph for end-tidal carbon dioxide (CO₂) monitor, precordial stethoscope, electrocardiogram, thermometer, and automated blood pressure cuff. Often, electromyography is used to avoid injury to the facial nerve. In these circumstances, neuromuscular blockade is avoided. Standard no oral intake (NPO) guidelines should be followed in nonemergent situations.

For mastoidectomy and tympanoplasty, the patient is positioned supine, with the head laterally rotated away from the affected side. It is important to carefully rotate the neck of a patient under general anesthesia because of the risk for atlantoaxial rotational subluxation (Brisson et al., 2000).

Induction of anesthesia can entail inhalational or intravenous induction. The anesthesiologist should consider endotracheal intubation without muscle relaxation or with a short-acting muscle relaxant so the facial nerve can be monitored during surgery. The use of nitrous oxide may be contraindicated during and after placement of the tympanic graft, because nitrous oxide accumulates in a closed gas space and increases the ambient pressure; some surgeons believe this tends to lift the graft away from its new site (Koivunen et al., 1996; Doyle and Banks, 2003).

The most common postoperative complication requiring unscheduled admission to the hospital for children who have undergone tympanomastoidectomy is postoperative nausea and vomiting (PONV) (Megerian et al., 2000). PONV has been attributed to surgical stimulation of the vestibular labyrinth, anesthetic techniques, or a combination of the two (Jellish et al., 1995; Dornhoffer and Manning, 2000). Propofol has antiemetic properties (Ved et al., 1996; Erb et al., 2002b). It appears that propofol used for induction and maintenance of anesthesia is superior to isoflurane or sevoflurane in reducing PONV after middle ear surgery (Jellish et al., 1995, 1999; Moore et al., 2003). The use of intravenous dexamethasone during surgery appears to decrease PONV in patients after undergoing tympanomastoid surgery (Liu et al., 2001).

Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) is a disorder of breathing during sleep characterized by prolonged partial upper airway obstruction (obstructive hypopnea) or intermittent complete obstruction (OSA) with or without snoring and associated with moderate to severe oxygen desaturation that disrupts normal sleep-time breathing and normal sleep patterns (American Thoracic Society, 1996). The most common cause of OSAS among children is upper airway narrowing with adenotonsillar hypertrophy. OSAS also occurs in infants and children with upper airway narrowing resulting from craniofacial anomalies, and in those with neuromuscular diseases, including cerebral palsy and muscular dystrophy (Marcus, 2001; Schwengel et al., 2009) (Box 24-1). See related video online at www.expertconsult.com.

In recent years, the epidemic increase in the prevalence of obesity during childhood seems to be contributing to substantial changes in the cross-sectional demographic and anthropometric characteristics of the children being referred for evaluation of OSAS. Although less than 15% of all symptomatic habitually snoring children were obese (i.e., >95th percentile for age and gender) in the early 1990s, more than 50% fulfilled the criteria for obesity among all referrals to a Kentucky sleep center by the mid 2000s (Gozal et al., 2006; Schwengel et al., 2009).

Adenotonsillar hypertrophy is the most common cause of OSAS in children. Many published papers, primarily case reports and case series, support the idea that tonsillectomy with or without adenoidectomy is often the cure for OSAS (Schechter et al., 2002; Garetz, 2008).

The peak prevalence of OSAS in children occurs between 2 and 8 years, which is the age when the tonsils and adenoids are large in relation to the child’s upper airways. The site of collapse is most commonly at the level of the adenoids or velopharynx (Isono et al., 1998; Isono, 2006). Although OSAS is associated with adenotonsillar hypertrophy, there must be other neuromuscular factors involved. These patients usually do not obstruct while awake, implying that sleep induces another dimension to OSAS. Some otherwise normal children with OSAS but with smaller tonsils and adenoids are cured by adenotonsillectomy, whereas others with larger tonsils and adenoids are not (Marcus, 2001). The patency of pharyngeal airway is maintained by tonic and phasic contractions of the upper airway dilator muscles, such as the genioglossus, geniohyoid, and velopalatine muscles (Isono, 2006). Compared with other inspiratory muscles (i.e., diaphragm and intercostal muscles), these upper airway muscles are preferentially depressed with sleep, sedatives, and general anesthetics (Ochiai et al., 1989, 1992) (see Chapter 3, Respiratory Physiology in Infants and Children). It is hypothesized that children with OSAS may have abnormal centrally mediated activation of their airway muscles, leading to a more collapsible upper airway (Marcus et al., 1994).

Fatty deposits of the upper airway structures, and subcutaneous fat deposits in the anterior neck region are the direct causes of airway obstruction in obese children (mostly adolescents), as well as in obese adults, with OSAS. In addition, increased adipose deposits in the chest wall and abdomen can reduce chest wall compliance as well as cephalad displacement of the diaphragm, causing inefficient ventilation by mass loading and decreased functional residual capacity of the lung (Dayyat et al., 2007; Schwengel et al., 2009). Obese patients have symptoms that differ from those in children with OSAS caused by adenotonsillar hypertrophy. Obese patients tend to have a significantly greater incidence of daytime sleepiness, insulin resistance, and systemic as well as pulmonary hypertension than children with adenotonsillar hypertrophy (Tauman et al., 2004). Furthermore, Tauman and coworkers recently observed a high failure rate for obese children with OSAS undergoing adentotonsillectomy.

Dayyat and colleagues (2007) differentiated between children with OSAS into two types. The type 1 child with OSAS is not obese but has disordered breathing secondary to marked lymphadenoid hypertrophy. The type 2 patient is obese with minimal lymphadenoid hyperplasia. Table 24-1 compares the common symptoms experienced by the two types of patients (Dayyat et al., 2007).

TABLE 24-1 Clinical Presentation of Pediatric Obstructive Sleep Apnea Types I and II

One of the most interesting areas of childhood OSAS research has been on the effects that OSAS has on systemic inflammation. Children with OSAS are at risk for developing inflammatory responses that may lead to endothelial dysfunction and atherogenesis (Gozal et al., 2008). School-aged children with OSAS have a higher serum C-reactive protein level than controls, and the elevation correlates with the severity of OSAS, and levels decrease after adenotonsillectomy (Gozal et al., 2007). Serum proteomic patterns in children with OSAS differ significantly from those in children who have primary snoring but do not have OSAS (Shah et al., 2006). In the Shah group’s study, proteomic profiling of serum samples in children with OSAS revealed differential expression of circulating proteins. Proteomics may play a future role in diagnosing OSAS in the snoring child.

Symptoms of OSAS include nocturnal snoring, breathing pauses, gasping, use of accessory muscles of respiration, enuresis, and excessive sweating (Messner, 2003). In addition, children with OSAS have a host of sequelae, which are usually reversible after adenotonsillectomy but can lead to perioperative complications during and after surgery. Children with OSAS may present with failure to thrive, although the cause of this growth failure is unclear (Sterni and Tunkel, 2003). Many of these children experience a growth spurt after surgery. Children with OSAS may have neurocognitive deficits such as poor learning, behavioral problems, and lower grades in school than non-OSAS children. Adenotonsillectomy improves functioning in these children (Marcus, 2001). Recent studies demonstrate that despite negative polysomnographic findings, the benefits of adenotonsillectomy are still observed in children with symptomatic airway obstruction, including improvements in behavior and quality of life (Leong and Davis 2007).

The diagnosis of OSAS is based on a thorough history and physical examination along with appropriate sleep studies, including polysomnography (Table 24-2 and Boxes 24-2 and 24-3). Snoring, increased respiratory efforts, periodic obstructive apnea, and oxygen desaturation while sleeping are the universal features of OSAS, which must be differentiated from the benign condition referred to as primary snoring.

TABLE 24-2 Polysomnographic Characteristics of Obstructive Sleep Apnea in Children and Adults

Polysomnography

Pediatric polysomnography includes measurement of end-tidal CO₂, electroencephalogram, chin EMG, chest wall movement, airflow through the nose and mouth, leg movement, and oxygen saturation via pulse oximetry (Box 24-4). After all events are reviewed and scored, several indices can be calculated. These include the apnea index and the apnea-hypopnea index, which are calculated for the entire sleep period, for both rapid eye movement sleep and non–rapid eye movement sleep. The term index refers to the number of events divided by the number of hours of sleep (Table 24-3). This calculation allows the comparison of polysomnograms of varying time lengths. The apnea index is determined using only apneas, whereas the apnea-hypopnea index includes both apneas and hypopneas (Wagner and Torrez, 2007).

TABLE 24-3 Respiratory Events that Can Be Seen During Polysomnography

It is helpful to divide the scores into severity-based categories (Table 24-4). OSAS severity can be used to determine the appropriate surgical center where the surgery should be performed and whether the child requires overnight observation (Box 24-5).

TABLE 24-4 Proposed Classification and Severity Criteria of Pediatric Sleep-Disordered Breathing

Although definitive diagnosis of OSAS is made by a positive polysomnogram, many children are not tested because the polysomnography laboratories specializing in children are few, and the tests are expensive and require an overnight stay (Sterni and Tunkel, 2003). Most children are diagnosed by recommendations set forth by the section of Pediatric Pulmonology Subcommittee on Obstructive Sleep Apnea, sans Polysomnography. This committee’s recommendations for otherwise healthy children older than 1 year are as follows (Schechter, 2002):

Severe, untreated OSAS may lead to pulmonary hypertension and cor pulmonale caused by nocturnal hypoxia and hypercarbia, resulting in compensatory changes in the pulmonary vasculature. Pulmonary vascular resistance increases, causing increased right ventricular strain. Severe cases may progress to pulmonary hypertension, arrhythmias, and cor pulmonale, which are reversible by performing early adenotonsillectomy (Miman et al., 2000). Children with OSAS also tend to have higher diastolic blood pressures. The cardiovascular changes appear to be the result of an increase in sympathetic tone that results from obstructive respiratory events (Marcus et al., 1998). Fortunately, few children develop clinically significant heart failure. It is prudent to pursue an aggressive cardiac evaluation if the child has a loud second heart sound, exercise intolerance, or diastolic hypertension. Because children are diagnosed earlier today, significant heart disease is rarely an issue (Marcus, 2001).

Preoperative Preparation

A careful review of the history, laboratory data, and physical examination results are essential for the optimal outcome of adenotonsillectomy. Careful evaluation of coagulation status is important before performing this procedure. If there is a history of easy bruising, frequent epistaxis, or positive family history, the prothrombin time, partial thromboplastin time, and platelet count should be obtained to rule out coagulopathies. In many pediatric institutions, a coagulation profile is obtained routinely for patients scheduled for adenotonsillectomy. However, in a prospective study of hemostatic assessment of patients before tonsillectomy, routine measurements of a coagulation profile were not useful predictors of postoperative bleeding (Close et al., 1994).

Although relatively mild, von Willebrand’s disease (i.e., reduced factor VIII, decreased platelet adhesiveness because of deficient von Willebrand factor) is the most common coagulopathy seen among patients scheduled for adenotonsillectomy. Children with von Willebrand’s disease or mild hemophilia A are treated preoperatively with desmopressin (1-desamino-8- d-arginine vasopressin [DDAVP]) (Prinsley et al., 1993). DDAVP is a synthetic analogue of vasopressin, which, in addition to its antidiuretic effect, stimulates endothelial cells and releases stored factor VIII and von Willebrand factor (Mannucci, 1988). The intravenous dosage of DDAVP is 0.3 mcg/kg, given over 20 minutes before anesthetic induction.

Patients who receive DDAVP are at increased risk for hyponatremia because of the retention of free water that occurs with DDAVP. Anesthesia care providers need to remember that intravenous fluids for these patients should be isotonic (preferably normal saline) and should be administered at one-half to two-thirds maintenance dosage. Patients who require intravenous fluids postoperatively should have their sodium monitored to assess for the development of hyponatremia.

The examiner should elicit a history of drug ingestion, especially acetylsalicylic acid. If the patient was given such drugs recently, surgery should be postponed, because these drugs cause platelet dysfunction for as long as 10 days and may cause excessive bleeding intraoperatively and postoperatively (Davies and Steward, 1977; Paradise, 2003).

During the preoperative visit, the patency of oral and nasal air passages is carefully examined. The patient’s mouth should be inspected for the degree of tonsillar hypertrophy or inflammation. The examiner should also have the child breathe with the mouth closed to evaluate the degree of nasal airway obstruction and estimate adenoidal hypertrophy. It is important to inspect the teeth routinely, because tonsillectomy is often performed on children who are losing their primary dentition. Any teeth missing preoperatively should be noted carefully. A tooth that is loose should be pointed out to the parent and child, with the explanation that it may be necessary to remove it while the child is anesthetized (it must then be saved). It is also possible for the surgeon to dislodge or chip teeth in the application of a mouth gag or during other intraoperative manipulations.

Anesthetic Management

All children should be monitored with a pulse oximeter, end-tidal CO₂ precordial stethoscope, electrocardiogram, thermometer, and automated blood pressure cuff. Oxygen saturation is determined in room air before the induction of anesthesia to establish the baseline value. If neuromuscular blockade is required, a nerve stimulator should be used to track the depth of paralysis. Standard NPO guidelines should be followed in nonemergent situations.

Children who are anxious preoperatively may receive sedation with oral midazolam. In older children scheduled for intravenous induction, EMLA cream (i.e., eutectic mixture of local anesthetics, 2.5% lidocaine and 2.5% prilocaine) is applied to the dorsum of both hands and sealed with plastic adhesives at least 1 hour before intravenous catheter insertion (see Chapter 9, Preoperative Preparation, and Chapter 13, Induction, Maintenance, and Recovery).

Adenoidectomy is a relatively short procedure (15 to 45 minutes), and many centers perform anesthesia without neuromuscular blockade and with less opioid than suggested in the following descriptions. Anesthesia is induced most commonly with oxygen, nitrous oxide, and sevoflurane. As with those undergoing myringotomies, children with adenotonsillar hypertrophy often have partial or complete nasal airway obstruction. The mouth must be kept open during the induction of anesthesia until the gag reflex is abolished and the oral airway is inserted. If necessary, moderate CPAP (10 to 15 cm H₂O), with jaw thrust during induction (before the patient is deep enough for oral airway insertion) helps to prevent the pharyngeal airway collapse that results from the relaxation of upper airway muscle tone (Reber et al., 2001; Bruppacher et al., 2003).

After the intravenous route is established, atropine or glycopyrrolate may be given for its anticholinergic effects. The patient’s trachea is intubated with a preformed oral (RAE) tube under deep inhalational anesthesia supplemented with a topical lidocaine spray to the vocal cords under a direct vision, an intravenous bolus of propofol, or an intermediate-acting, nondepolarizing muscle relaxant (e.g., cisatracurium, vecuronium). In older children, anesthesia may be induced intravenously with propofol (2 to 3 mg/kg) mixed with lidocaine (1 to 2 mg/mL of propofol) to reduce pain at the injection site, with or without anticholinergic agent or a muscle relaxant. Inhalation anesthetic or propofol infusion is continued thereafter with spontaneous or controlled ventilation. A cuffed endotracheal tube is recommended to reduce the chance of aspiration of blood and secretions and to reduce gas leaks around the tube. A cuffed endotracheal tube, 0.5 to 1.0 mm (inner diameter) smaller than the age-appropriate size, should be chosen to accommodate the passage of the cuff through the subglottis (Khine et al., 1997; James, 2001; Fine and Borland, 2004). The endotracheal tube is immobilized with adhesive tape over the middle of the lower lip (Fig. 24-4). The breath sounds on both sides of the chest should be auscultated carefully to avoid endobronchial intubation. The endotracheal tube is then held in place by the groove-bladed tongue depressor that is a part of the Ring adaptation of the Brown-Davis mouth gag (Fig. 24-5).

FIGURE 24-4 For tonsillectomy or adenoidectomy, an oral Ring, Adaire, Ellwyn (RAE) endotracheal tube is fixed over the middle of the lower lip.

FIGURE 24-5 Patient in position for tonsillectomy. A Brown-Davis mouth gag holds the mouth open. An oral Ring, Adaire, Ellwyn (RAE) endotracheal tube is fixed to the middle of the lower lip and is held in the groove of the tongue blade.

Anesthesia is maintained with supplemental opioids to reduce the requirement of the anesthesia maintenance agent and to provide postoperative analgesia. The physician may start with a loading dose of 1 to 2 mcg/kg of fentanyl, 50 to 100 mcg/kg of morphine, or 10 to 20 mcg/kg of hydromorphone given intravenously, with additional doses administered as needed. Children with moderate and severe OSAS should receive lower dosages of opioids to minimize the risk for prolonged apnea during emergence and postoperative upper airway obstruction. Brown and coworkers (2004) have shown that young age and low preoperative oxygen saturation were associated with lower postoperative morphine requirement. It appears that children with a minimal oxygen saturation of 85% or less during preoperative sleep required half the postoperative analgesic dosage required by children whose saturations were 85% or greater (Brown et al., 2006).

The use of NSAIDs during or after tonsillectomy is controversial. A meta-analysis suggested that there is an increased risk for bleeding and increased return to the operating room when NSAIDs such as ketorolac are used (Marret, 2003). Criticism of this meta-analysis focuses on the small number of patients evaluated, the varying types and dosages of NSAID, and the varying surgical techniques used for the tonsillectomy. A Cochrane database review evaluated the role of NSAIDs in posttonsillectomy bleeding and found no significant correlation between NSAID use and increased risk for posttonsillectomy bleeding (Cardwell et al., 2005). Practice among pediatric anesthesiologists varies. Some centers do not use NSAIDs during adenoidectomy or tonsillectomy, whereas others use them routinely (Allford, 2009).

There is evidence that high dosages of dexamethasone (up to 1 mg/kg, 25 mg maximum) reduce postoperative swelling and pain and decrease the incidence of PONV without apparent adverse effects attributable to dexamethasone (Pappas et al., 1998). Children receiving dexamethasone are more likely to advance to a soft-solid diet on the first postoperative day (Steward et al., 2003).

Bleeding during tonsil and adenoid surgery is seldom excessive, but massive hemorrhage has occurred with tearing of the carotid vessels (Smith, 1972, 1980). Homeostasis is usually obtained using electrocautery. There have been several reports of fires due to electrocautery-induced ignition of the endotracheal tube or packing during tonsillectomy. Fires are caused by combustible material in an oxygen-rich environment (Mattucci and Militana, 2003); management of airway fires is discussed later.

Children with OSAS tend to emerge from anesthesia more slowly than children without OSAS. This may be explained by their deficit in sleep arousal mechanisms. They seem to have elevated sleep arousal mechanisms in response to hypercarbia and increased upper airway obstruction (Marcus et al., 1998, 1999). Other subtle disturbances of sleep architecture may also be present (Bandla et al., 1999).

Techniques of Tonsillectomy and Adenoidectomy

A myriad of surgical techniques are used to perform tonsillectomy and adenoidectomy, and they use a mouth gag to give oropharyngeal exposure. The surgeon should use caution when placing and removing the mouth gag to avoid displacement of the endotracheal tube.

The adenoidectomy is performed either with a mechanical or a thermal technique (Hesham, 2009). Mechanical removal of the adenoids may be performed using curettes, adenotomes, or a micro-debrider. These mechanical techniques require nasopharyngeal packing to prevent bleeding, and the surgeon must remember to remove the packing at the end of the procedure. Thermal removal of adenoid tissue may employ electrosurgical cautery, radiofrequency ablation, or lasers, and it usually results in little bleeding.

Tonsillectomy can also be performed via mechanical or thermal techniques. Intracapsular removal of tonsil tissue is a newer approach that preserves the integrity of the tonsil capsule, and will be discussed later.

Mechanical removal of the tonsil has many technical variations. In general, an incision is made in the anterior pillar mucosa to expose the tonsil capsule, and using sharp or blunt dissection, the tonsil and capsule are removed together. Alternatively, a guillotine, or snare, is occasionally used to remove the tonsil without making an incision. This results in exposure of the underlying pharyngeal musculature with the perforating vascular supply to the tonsil, and hemostasis must be established. At the turn of the previous century, snare tonsillectomy with ether anesthesia was the standard, and hemostasis was achieved after prolonged observation of the surgical field to ensure passive wound clotting. This was less than ideal, and the mortality rate was unacceptably high. Today, active hemorrhage control is performed after removal of the tonsils. Some surgeons use dissolvable suture to ligate the bleeding points, but this is becoming less common. More often, electrosurgical cautery is used for hemostasis. This technique completes an electrical arc between the patient and the surgical instrument and has the potential to ignite flammable gases and combustible materials (such as the sponges in the nasopharynx used for tamponade of the adenoid bleeding). Case reports of airway fires have been reported with the use of electrosurgical cautery in tonsillectomy (Mattucci and Militana, 2003). It is suggested that the inspired oxygen levels be maintained as they are for the use of lasers in the airway (see Laser Surgery of the Larynx, later).

Thermal removal of the tonsil uses the electrosurgical unit or a radiofrequency unit for tonsil dissection. The most common radiofrequency unit in use is Coblation (ArthroCare, Austin, TX). Thermal removal of the tonsils and adenoids generally results in less blood loss, but it may be accompanied by slightly more postoperative pain than other techniques. A cuffed endotracheal tube, using moist throat packing and inspired oxygen levels of less than 40%, will minimize the risk for an airway fire (Johnson et al., 2002).

Intracapsular tonsillectomy is a newer technique that uses either the micro-debrider or the radiofrequency ablator to remove the tonsil tissue while preserving the tonsil capsule (Koltai et al., 2002). In effect, this may be considered a selective removal of the tonsillar mass, which is believed to be the most common cause of OSAS. Preservation of the capsule protects the underlying pharyngeal musculature, resulting in less postoperative pain and hemorrhage. Because the vascular supply is interrupted at a more terminal point, the muscular bed can contract around the vessels, providing better hemostasis. Initially, this technique was recommended only for those patients with OSAS. Recurrent infection is considered a contraindication, because this technique leaves behind residual tonsil tissue that may become reinfected. This technique is especially appropriate in those OSAS children 3 years of age and younger because of the lower postoperative pain scores and thus less opioid need (Solares et al., 2005; Colen et al., 2008). In general, the only risk of an intracapsular tonsillectomy is the rare (<1 in 1500) need to return for a complete tonsillectomy because of tissue regrowth leading to recurrent infectious tonsillitis.

At the conclusion of surgery, the surgeon usually suctions the pharynx and larynx under direct vision to prevent bleeding caused by agitation of raw mucosal surfaces by a suction catheter. Suctioning of the stomach contents may also remove swallowed secretions, blood, or residual preoperative sedative medications. Removal of these preoperative medications may decrease excess sedation in the postoperative period. Some surgeons elect to infiltrate 0.25% bupivacaine or other local anesthetic medications into the tonsillar fossa to aid in postoperative pain relief (Naja et al., 2005), whereas others feel that this analgesic technique may lead to premature discharge of patients who will then experience rebound pain when the local anesthetic wears off. This practice has occasionally been associated with airway obstruction after extubation.

After tonsillectomy, the anesthesia provider should always use a tonsil suction tip and should never blindly suction the nasopharynx or oropharynx after adenoidectomy or tonsillectomy. Suctioning should be directed toward the midline to avoid the lateral tonsil fossa. A soft nasopharyngeal airway may be inserted to facilitate airway patency for extubation. If adenoid hemostasis is adequate prior to insertion of the nasopharyngeal airway, usually no additional bleeding is encountered. Toward the completion of surgery, before a child regains active reflexes, the anesthesiologist should auscultate both sides of the chest to rule out the presence of aspirated blood or secretions and, under direct laryngoscopic visualization, examine the mouth and pharynx for blood and other debris that could cause airway irritation after extubation.

Laryngospasm may occur when the patient is extubated after tonsillectomy. Methods for avoiding this problem include extubating the trachea while the child is deeply anesthetized (not recommended for children with OSAS) or almost completely awake (see Chapter 13, Induction, Maintenance, and Recovery). Although intravenous lidocaine has not consistently proved helpful in preventing laryngospasm, application of local anesthetic before intubation or manipulation of the airway can reduce the incidence of laryngospasm during intubation and after extubation (Leicht et al., 1985; McCulloch et al., 1992; Landsman, 1997). It appears that lidocaine deposited locally in the laryngeal area suppresses laryngeal mucosa neuroreceptor transmission. However, lidocaine’s duration of action at laryngeal receptor sites is only 30 minutes, and its administration before intubation may not protect against laryngospasm at the time of extubation (Warner, 1996).

Before extubation, the lungs should be well expanded with an oxygen-air mixture at sustained high positive pressure (35 to 40 cm H₂O) several times (the vital capacity maneuver), to reopen intrathoracic airways and reverse atelectasis, which frequently develops during anesthesia and surgery; the patient should then be extubated under positive pressure (Benoit et al., 2002; Tusman et al., 2003) to prevent postoperative oxygen desaturation. Positive airway pressure at the moment of extubation causes a coughing motion, which helps to expel secretions around the vocal cords. Positive extending pressure on the upper airway walls also attenuates the excitation of the superior laryngeal nerve and may diminish the risk for laryngospasm (Suzuki and Sasaki, 1977; Sasaki, 1979) (see Chapter 3, Respiratory Physiology in Infants and Children, and Chapter 13, Induction, Maintenance, and Recovery).

Postoperative Management

Children with hypertrophic tonsils and adenoids tend to have increased airway obstruction in the immediate postoperative period. The presence of blood and secretions in the pharynx and larynx may provoke upper airway reflexes, leading to laryngospasm. These patients tend to become hypoxemic more often and perhaps more severely during the first several hours after surgery than patients undergoing procedures not involving the upper airways (Motoyama and Glazener, 1986). However, they seem to maintain their preoperative levels of oxygen saturation in room air thereafter, as determined with pulse oximetry (Motoyama and Borland, unpublished observations). Fortunately, serious complications after adenotonsillectomy are infrequent. Postoperative hemorrhage, however, does occur and can become a life-threatening catastrophe (discussed later). Postoperative emesis is relatively common because of pharyngeal mucosal irritation from surgery, which may stimulate the glossopharyngeal nerves, or from bloody secretions that are swallowed. It is therefore prudent for the anesthesiologist to administer antiemetics (e.g., ondansetron or metoclopramide) prophylactically, in addition to dexamethasone before the end of surgery (Pappas et al., 1998). Pain after tonsillectomy is mild to moderate and may be controlled by opioids given intraoperatively as part of anesthetic management or by supplementation (morphine, 50 mcg/kg; fentanyl, 0.5 to 1.0 mcg/kg; hydromorphone, 10 mcg/kg) in the postanesthetic care unit. Postoperative pain after adenoidectomy is relatively mild. Acetaminophen is a good adjunct to pain control in these patients.

It has been reported that children with OSAS have reduced opioid requirements after adenotonsillectomy. In addition, children with OSAS spontaneously breathing during halothane anesthesia are more likely to become apneic than non-OSAS children when treated with the same dosage of fentanyl (Waters et al., 2002). However, others have found no morbidity from opioid or benzodiazepine treatment in OSAS pediatric patients undergoing adenotonsillectomy (Helfaer et al., 1996; Sanders et al., 2006; Leong and Davis, 2007).

Preoperative sedation with benzodiazepines and postoperative treatment with opioids should be tailored to meet the needs of the patient. It would be prudent to titrate opioids, anticipating that the more severe the OSAS, the higher is the risk of opioid and benzodiazepine sensitivity. For patients with moderate or severe OSAS, many anesthesiologists prefer not to administer opioids until the patient has fully emerged from the anesthetic, has regained spontaneous ventilation, has been extubated, and is able to maintain an open airway with spontaneous ventilation. The patient’s opioid therapy may then be titrated carefully to achieve analgesia without respiratory compromise (Leong and Davis, 2007). During the immediate postoperative period, monitoring these patients in a postanesthetic care unit staffed with pediatric recovery room nurses allows a safe postoperative recovery with pain control.

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