Sleep apnea is defined as a pause in breathing during sleep lasting ≥10 seconds and accompanied by at least a 4% decline in oxygen saturation from baseline despite continued respiratory efforts. Hypopnea is defined as an incomplete reduction of airflow lasting ≥10 seconds, with 50% or more reduction in tidal volume. The Apnea-Hypopnea Index is the number of apnea and hypopnea occurrences per hour during sleep (see Table 2-1). Obstructive sleep apnea (OSA) is defined as the repetition of these apneic or hypopneic spells ≥5 times per hour with symptoms associated with sleep-disordered breathing (eg, daytime hypersomnolence, cor pulmonale, and polycythemia).
The essential feature of OSA in children is increased airway resistance during sleep. Adenotonsillar hypertrophy, allergic rhinitis, turbinate hypertrophy, deviated septum, and maxillary constriction can cause airway narrowing in children. Other factors include abnormal central arousal disorder, abnormal bony anatomy, disordered neural control of airway caliber or sensation, and decreased pharyngeal tone in patients with neuromuscular conditions such as may be seen in certain types of cerebral palsy. There is an increased incidence of OSA among children with syndromes affecting their upper airway (mandibular hypoplasia in Treacher Collins or Pierre Robin syndrome; maxillary hypoplasia in Crouzon, Apert, or Pfeiffer syndrome; relative macroglossia in Down syndrome). Therefore, OSA is often a multifactorial disorder with overlapping influences that together predispose the patient to obstructed breathing.
Some 1-3% of children have OSA, and morbidities associated with OSA include symptoms of habitual problems (pauses, snorts, and gasps), daytime behavioral problems, enuresis, disturbed sleep, and daytime somnolence. It may result in a significant degree of hypercarbia and hypoxemia, leading to neurocognitive impairment, failure to thrive, dyspnea, systemic or pulmonary hypertension, and even death from cor pulmonale or arrhythmias.
The peak incidence of OSA occurs between 2 and 6 years of age and is related to when a physiological enlargement of tonsils and adenoids has occurred relative to the midfacial skeleton, which significantly expands from 6 years of age.
Key questions to ask parents during the preoperative evaluation:
Does your child have difficulty breathing during sleep?
Have you observed symptoms of apnea?
Have you observed sweating while your child sleeps?
Does your child have restless sleep?
Does your child breathe through his/her mouth when awake?
Are you worried about your child’s breathing at night?
Do you have any family history of obstructive sleep apnea, sudden infant death syndrome, or apparent life-threatening events?
Does your child have behavioral problems?
Overnight polysomnography is the gold standard for the diagnosis of OSA. Overnight home pulse oximetry also provides a useful stratification of severity and may predict postoperative complications. For example, pediatric patients with significant OSA, defined as 85% or less oxygen saturation, have an increased sensitivity to opioids. Children with an oxygen saturation nadir of <85% on polysomnography required half the morphine dose needed by those with less desaturation to achieve the same level of analgesia.
Cardiac evaluation, specifically echocardiography, is recommended for any child with signs of right ventricular dysfunction, systemic hypertension, or multiple episodes of desaturation below 70%.
Noninvasive nasal positive-pressure ventilation is a common medical treatment for OSA in children. Children with very severe OSA who are at risk for persistent OSA and those with cardiovascular complications from OSA should be considered for preoperative continuous positive airway pressure/bilevel positive airway pressure (CPAP/BiPAP) therapy. Effective CPAP/BiPAP therapy may improve pulmonary hypertension and reduce the patient’s surgical risks. The child’s preoperative CPAP/BiPAP regimen can also be used in postoperative care.
Adenotonsillectomy is the surgical treatment of choice for children with OSA.