TY - JOUR T1 - Mechanical response to electrical- and neuro-stimulation of the genioglossus (GG) in propofol-sedated OSA patients JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - 1424 AU - Yaniv Dotan AU - Louis Gaitini AU - Arie Oliven Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/1424.abstract N2 - Pharyngeal collapsibility during sleep is believed to increase primarily due to decline in dilator muscle activity. However, it is well documented that GG-EMG increases during apneas and hypopneas. The magnitude of increase is limited, however, as arousal terminates the respiratory disturbance. In the present study we prevented arousal by “drug-induced sleep” with propofol. We induced prolonged hypopneas in 17 patients with OSA by lowering CPAP after discontinuation of propofol, and monitored GG-EMG, flow and the area (CSA) at the site of collapse (pharyngoscopy) until arousal. Prolonged hypopnea triggered a dramatic increase in GG-EMG. The mechanical response to this physiological drive to the GG was compared to baseline condition (after lowering CPAP from holding pressure), electrical stimulation (ES) of the GG, and after arousal.View this table:Before arousal from sedation, flow remained unchanged despite the large increase in GG-EMG activity, while inspiratory CSA decreased. ES of GG, however, increased CSA and flow. Arousal resulted in fast enlargement of CSA and restoration of unobstructed flow, associated with marked reduction in GG EMG. We conclude that during propofol-induced sedation (and presumably also during sleep), pharyngeal collapse is due to inadequate mechanical response to activation of the GG, which occurs despite the well preserved mechanical response of this muscle to ES. ER -