Overnight oximetry as a screening tool for moderate to severe obstructive sleep apnoea in South African children

Background. Obstructive sleep apnoea (OSA) is common in children yet often overlooked, as symptom-based screening is unreliable. Polysomnography is regarded as the gold standard for the diagnosis of OSA, but is not widely available in South Africa (SA). Overnight oximetry is a validated screening tool for OSA.Objectives. To describe the impact and utility of overnight oximetry at a tertiary children’s hospital in SA.Methods. A retrospective descriptive study was conducted of patients screened for OSA by overnight oximetry at a paediatric referral hospital from December 2012 to December 2014. Clinical data were retrieved from the oximetry database and medical records. Recordings of ≥6 hours were considered adequate and included in the study. OSA severity was determined using the McGill score. Details on management and outcome were documented.Results. Oximetry studies in 137 of 153 patients were suitable for analysis (88 males (64.2%), median age 31.4 months (interquartile range (IQR) 15.8 - 65.8). Adenotonsillar hypertrophy was common (n=97, 70.8%), and 65 children (47.4%) had two or more underlying OSA risk factors. McGill’s score classified patients as follows: no/mild OSA n=55 (40.1%), moderate OSA n=23 (16.8%), severe OSA n=23 (16.8%) and very severe OSA n=36 (26.3%). Male gender, adenotonsillar hypertrophy and a lower weight-for-age z-score (–1.3 v. –0.7; p=0.038) were associated with severe to very severe OSA. Seventy-eight children (56.9%) were referred for surgery, 33 (24.1%) receiving urgent surgery within a median of 6 days (IQR 4 - 12). In contrast, 59 children (43.1%) with suspected OSA did not require surgical intervention.Conclusions. Overnight oximetry is a simple low-cost tool to assess severity of OSA and prioritise appropriate OSA management in resource-constrained settings such as SA.