Identifying Children at Risk for Complications after Adenotonsillectomy. Wilson et al. (page 313)
Hypothesizing that assessment for obstructive sleep apnea (OSAS) might help predict risk for postadenotonsillectomy respiratory complications, Wilson et al. undertook a retrospective chart review of children referred for sleep studies at their institution. Out of 349 children referred for such studies between 1992 and 1998, 163 children had received adenotonsillectomy without concomitant procedures within 6 months of their referral. These were the patients whose medical charts were included in this study.
Authors grouped both home and laboratory polysomnography assessments under the general name of cardiorespiratory sleep study, or CRSS. Each patient's CRSS record was analyzed for several variables, and the study reports on the following four parameters: the apnea and hypoapnea index (OAH index), the oxygen saturation (SaO2) nadir, the desaturation index, and the percent time less than 90% saturation (T < 90%). The OAH index was defined as the number of respiratory events (apnea and hypoapnea) per hour of sleep. The severity of sleep-disordered breathing was classified as normal, mild, moderate, or severe depending on the number of episodes (from less than 1 to more than 5). The SaO2nadir was defined as the minimum oxygen saturation occurring during sleep, regardless of its duration.
Next, the investigators identified respiratory complications (such as desaturation and airway obstruction) and medical interventions (such as reintubation and positive pressure ventilation) noted in the patients’ postoperative medical records. Children who required interventions were further divided into minor and major intervention groups. There were 34 children (21% of the study population) who had required a medical intervention after respiratory complications. Ten required a major intervention (reintubation, admission to the intensive care unit) and 24 required a minor intervention (such as oxygen therapy beyond the usual period). Fourteen of those requiring a minor intervention (58%) had shown a preoperative SaO2nadir equal to or less than 80%, while 50% of the children requiring a major intervention had shown similar SaO2nadir values.
The authors identified age and presence of an associated medical condition as clinical predictors of postoperative respiratory complications. An OAH index of equal to or more than 5 events per hour, and a preoperative nocturnal SaO2nadir of equal to or less than 80% significantly increased the incidence of respiratory complications. Mild, moderate, and severe OSAS were associated with a 6, 14, and 31% incidence of respiratory complications respectively. Determination of nocturnal oxygen saturation may prove not only a cost-effective way to diagnose severe OSAS, but also to predict postoperative risk for complications in children about to undergo adenotonsillectomy.