Abdominal compression increases upper airway collapsibility during sleep in obese male obstructive sleep apnea patients

Study objectivesAbdominal obesity, particularly common in centrally obese males, may have a negative impact on upper airway (UA) function during sleep. For example, cranial displacement of the diaphragm with raised intra-abdominal pressure may reduce axial tension exerted on the UA by intrathoracic structures and increase UA collapsibility during sleep.DesignThis study aimed to examine the effect of abdominal compression on UA function during sleep in obese male obstructive sleep apnea patients.SettingParticipants slept in a sound-insulated room with physiologic measurements controlled from an adjacent room.ParticipantsFifteen obese (body mass index: 34.5 +/- 1.1 kg/m2) male obstructive sleep apnea patients (apnea-hypopnea index: 58.1 +/- 6.8 events/h) aged 50 +/- 2.6 years participated.InterventionsGastric (PGA) and transdiaphragmatic pressures (P(DI)), UA closing pressure (UACP), UA airflow resistance (R(UA)), and changes in end-expiratory lung volume (EELV) were determined during stable stage 2 sleep with and without abdominal compression, achieved via inflation of a pneumatic cuff placed around the abdomen. UACP was assessed during brief mask occlusions.Measurements and resultsAbdominal compression significantly decreased EELV by 0.53 +/- 0.24 L (P=0.045) and increased PGA (16.2 +/- 0.8 versus 10.8 +/- 0.7 cm H2O, P ConclusionsAbdominal compression negatively impacts on UA collapsibility during sleep and this effect may help explain strong associations between central obesity and obstructive sleep apnea.Daniel L. Stadler, R. Doug McEvoy, Kate E. Sprecher, Kieron J. Thomson, Melissa K. Ryan, Courtney C. Thompson, Peter G. Catchesidehttp://www.ncbi.nlm.nih.gov/pubmed/2004159