TY - JOUR T1 - Effects of pentobarbital on upper airway patency during sleep JF - European Respiratory Journal JO - Eur Respir J SP - 569 LP - 576 DO - 10.1183/09031936.00153809 VL - 36 IS - 3 AU - M. Eikermann AU - D.J. Eckert AU - N.L. Chamberlin AU - A.S. Jordan AU - S. Zaremba AU - S. Smith AU - C. Rosow AU - A. Malhotra Y1 - 2010/09/01 UR - http://erj.ersjournals.com/content/36/3/569.abstract N2 - We hypothesised that pentobarbital would improve upper airway mechanics based on an increase in latency to arousal and amplitude of the phasic genioglossus electromyogram (EMG), and a decrease in the active upper airway critical closing pressure (Pcrit). 12 healthy subjects received pentobarbital (100 mg) or placebo in a double-blind, crossover protocol. During wakefulness, we measured the genioglossus reflex response to negative pressure pulses. During sleep, carbon dioxide was insufflated into the inspired air. Airway pressure was then decreased in a stepwise fashion until arousal from sleep. With basal breathing during sleep: flow rate was lower in volunteers given pentobarbital; end-tidal CO2 concentration and upper airway resistance were greater; and Pcrit was unaffected (pentobarbital mean±sd -11.7±4.5 versus placebo -10.25±3.6 cmH2O; p = 0.11). Pentobarbital increased the time to arousal (297±63s versus 232±67 s; p<0.05), at which time phasic genioglossus EMG was higher (6.2±4.8% maximal versus 3.1±3%; p<0.05) as were CO2 levels. The increase in genioglossus EMG after CO2 administration was greater after pentobarbital versus placebo. Pentobarbital did not affect the genioglossus negative-pressure reflex. Pentobarbital increases the time to arousal and stimulates genioglossus muscle activity, but it also increases upper airway resistance during sleep. ER -