Quantitative effects of head rotation angle on apnea hypopnea index in positional obstructive sleep apnea – a preliminary case series

Abstract Objectives Quantify the effects of head rotation and head incline on obstructive sleep apnea (OSA) severity. Design Single-arm, intervention study. Setting Pulmonary specialty clinic. Case presentation Ten adults diagnosed with positional OSA ranging from 32 to 64 years of age 6 females, 4 males reporting persistent daytime sleepiness and health issues with consistent use of CPAP. Intervention Standard polysomnography with a head angle sensor attached to the forehead and coaching to fall asleep with head at various rotation and incline angles and torso in supine and non-supine positions. Measurements OSA severity was scored according to American Academy of Sleep Medicine guidelines. Apnea hypopnea index (AHI) and peripheral capillary oxygen (SpO2) saturation were measured during each sleep epoch of unique head rotation, head incline, and torso position. Results Two participants (1 with no apneas and 1 with central sleep apnea) were excluded. Among the remaining 8 participants, average reduction in peak AHI was 66% (range 18–88%) with head rotation ≤ 20° above the horizon compared with > 20° above the horizon. The average of peak AHI values with head rotation ≤ 20° was significantly lower than with head rotation > 20° (20.0 vs 45.3, P = 0.002). Minimum SpO2 was significantly higher for head rotation ≤ 20° compared with > 20° (mean: 90.6% vs 84.3%, P = 0.03). In the torso supine position, average peak AHI was significantly lower with head rotation ≤ 20° compared with > 20° (7.1 vs 52.1, P P = 0.09). Conclusion These results support further exploration of maintaining head position ≤ 20° above the horizon to minimize AHI and oxygen desaturation in OSA patients. Trial registration Apnea Hypopnea Index Severity Versus Head Position During Sleep. ClinicalTrials.gov Identifier: NCT04086407 September 11, 2019 Registered retrospectively.