Quantitative effects of trunk and head position on the apnea hypopnea index in obstructive sleep apnea

Abstract

Study Objectives: To test the hypothesis that head position, separately from trunk position, is an additionally important factor for the occurrence of apnea in obstructive sleep apnea (OSA) patients. Design: Prospective cohort study. Setting: St. Lucas Andreas Hospital, Amsterdam, the Netherlands. Patients and Participants: Three hundred patients referred to our department because of clinically suspected OSA. Interventions: N/A Measurements and Results: Patients underwent overnight polysomnography with 2 position sensors: one on the trunk, and one in the mid-forehead. Of the 300 subjects, 241 were diagnosed with OSA, based on an AHI > 5. Of these patients, 199 could be analyzed for position-dependent OSA based on head and trunk position sensors (AHI in supine position twice as high as AHI in non-supine positions): 41.2% of the cases were not position dependent, 52.3% were supine position dependent based on the trunk sensor, 6.5% were supine position dependent based on the head sensor alone. In 46.2% of the trunk supine position-dependent group, head position was of considerable influence on the AHI (AHI was > 5 higher when the head was also in supine position compared to when the head was turned to the side). Conclusions: The results of this study confirm our hypothesis that the occurrence of OSA may also be dependent on the position of the head. Therefore in patients with a suspicion of position-dependent OSA, sleep recording with dual position sensors placed on both trunk and head should be considered.