Mouth breathing during sleep and persistence of OSA after adeno-tonsillectomy in non-obese children

Objective: To evaluate the relationship between the percentage of total sleep time with mouth breathing (SMBP) and post-adeno-tonsillectomy apnea-hypopnea index (AHI) in non-obese children. Materials and Methods: Non-obese obstructive sleep apnea (OSA) children with pre- and post- TandA PSG done between August 2011 and February 2019 were reviewed and mouth breathing during sleep was manually scored. Percentage of total sleep time with mouth breathing (SMBP) was calculated. Its correlation with post-operative AHI >1.5/h was studied. Results: Fifty-nine children were included in the analysis and 47 of the study group (79.7%) were male. The mean age at pre-operative PSG was 9.2+/-3.1 years. The mean AHI dropped from 8.3+/-19.8 to 4.1+/-11.6 (P < 0.001). Thirty-one (50.8%) were cured of OSA defined as AHI<=1.5/h. There was a statistically significant positive correlation between post-operative log-transformed AHI and log-transformed SMBP (r=0.265, P = 0.044). The optimal SMBP for detecting residual OSA was 10.5%. The sensitivity, specificity, positive predictive value, negative predictive value and Youden Index were 0.86, 0.37, 0.57, 0.73 and 0.23, respectively. Post-operative children with SMBP >10.5% had higher risk for residual OSA (OR 4.2, 95%CI: 1.2–15.0, P = 0.029). Conclusion: Obstructive sleep apnea children with mouth breathing for more than 10.5% of total sleep time are more likely to have residual OSA after TandA.