title: Neural Respiratory Drive and Arousal in Patients with Obstructive Sleep Apnea Hypopnea.
abstract: OBJECTIVE
  It has been hypothesized that arousals after apnea and hypopnea events in patients with obstructive sleep apnea are triggered when neural respiratory drive exceeds a certain level, but this hypothesis is based on esophageal pressure data, which are dependent on flow and lung volume. We aimed to determine whether a fixed threshold of respiratory drive is responsible for arousal at the termination of apnea and hypopnea using a flow independent technique (esophageal diaphragm electromyography, EMGdi) in patients with obstructive sleep apnea.
  
  
  METHODS
  Sleep center of state Key Laboratory of Respiratory Disease.
  
  
  METHODS
  Seventeen subjects (two women, mean age 53 ± 11 years) with obstructive sleep apnea/hypopnea syndrome were studied.
  
  
  METHODS
  We recorded esophageal pressure and EMGdi simultaneously during overnight full polysomnography in all the subjects.
  
  
  RESULTS
  A total of 709 hypopnea events and 986 apnea events were analyzed. There was wide variation in both esophageal pressure and EMGdi at the end of both apnea and hypopnea events within a subject and stage 2 sleep. The EMGdi at the end of events that terminated with arousal was similar to those which terminated without arousal for both hypopnea events (27.6% ± 13.9%max vs 29.9% ± 15.9%max, P = ns) and apnea events (22.9% ± 11.5%max vs 22.1% ± 12.6%max, P = ns). The Pes at the end of respiratory events terminated with arousal was also similar to those terminated without arousal. There was a small but significant difference in EMGdi at the end of respiratory events between hypopnea and apnea (25.3% ± 14.2%max vs 21.7% ± 13.2%max, P < 0.05].
  
  
  CONCLUSIONS
  Our data do not support the concept that there is threshold of neural respiratory drive that is responsible for arousal in patients with obstructive sleep apnea.
authors: State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China.
authors: Si-Chang
authors: SC
authors: Xiao
authors: State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China.
authors: Bai-Ting
authors: BT
authors: He
authors: Lane Fox Respiratory Unit, Sleep Disorders Centre, Guy's & St Thomas' NHS Foundation Trust, London, UK.|Department of Respiratory Medicine, King's College London School of Medicine, London, UK.
authors: Joerg
authors: J
authors: Steier
authors: Department of Respiratory Medicine, King's College London School of Medicine, London, UK.
authors: John
authors: J
authors: Moxham
authors: NIHR Respiratory Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, UK.
authors: Michael I
authors: MI
authors: Polkey
authors: State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China.
authors: Yuan-Ming
authors: YM
authors: Luo
mesh_terms: D000368:Aged; D001143:Arousal; D003964:Diaphragm / Q000502:physiology; D004328:Drive; D004576:Electromyography; D004947:Esophagus / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011312:Pressure; D012119:Respiration; D012120:Respiration Disorders / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D012894:Sleep Stages
keywords: OSA; arousal; diaphragm EMG; esophageal pressure; hypopnea