Nocturnal pulse oximetry as an abbreviated testing modality for pediatric obstructive sleep apnea

Objective. To determine the utility of pulse oximetry for diagnosis of obst ructive sleep apnea (OSA) in children. Methods. We performed a cross-sectional study of 349 patients referred to a pediatric sleep laboratory for possible OSA. A mixed/obstructive apnea/hyp opnea index (MOAHI) greater than or equal to 1 on nocturnal polysomnography (PSG) defined OSA. A sleep laboratory physician read nocturnal oximetry tr end and event graphs, blinded to clinical and polysomnographic results. Lik elihood ratios were used to determine the change in probability of having O SA before and after oximetry results were known. Results. Of 349 patients, 210 (60%) had OSA as defined polysomnographically . Oximetry trend graphs were classified as positive for OSA in 93 and negat ive or inconclusive in 256 patients. Of the 93 oximetry results read as pos itive, PSG confirmed OSA in 90 patients. A positive oximetry trend graph ha d a likelihood ratio of 19.4, increasing the probability of having OSA from 60% to 97%. The median MOAHI of children with a positive oximetry result w as 16.4 (7.5, 30.2). The 3 false-positive oximetry results were all in the subgroup of 92 children who had diagnoses other than adenotonsillar hypertr ophy that might have affected breathing during sleep. A negative or inconcl usive oximetry result had a likelihood ratio of .58, decreasing the probabi lity of having OSA from 60% to 47%. Interobserver reliability for oximetry readings was very good to excellent (kappa = .80). Conclusions. In the setting of a child suspected of having OSA, a positive nocturnal oximetry trend graph has at least a 97% positive predictive value . Oximetry could: 1) be the definitive diagnostic test for straightforward OSA attributable to adenotonsillar hypertrophy in children older than 12 mo nths of age, or 2) quickly and inexpensively identify children with a histo ry suggesting sleep-disordered breathing who would require PSG to elucidate the type and severity. A negative oximetry result cannot be used to rule o ut OSA.