title: Inspiratory effort sensation to added resistive loading in patients with obstructive sleep apnea.
abstract: OBJECTIVE
  Repeated episodes of upper-airway occlusion are the main characteristics of patients with obstructive sleep apnea (OSA) during sleep. It has been reported that an impairment in the sensation of detection and a depression of ventilatory compensation to added load could be observed in such patients. In this study, we examined patients with OSA to evaluate the inspiratory effort sensation (IES), ventilation, and mouth occlusion pressures during added resistive loading while awake and to determine whether they can be reversed by nasal continuous positive airway pressure (CPAP) treatment.
  
  
  METHODS
  A hospital-based case-control study.
  
  
  METHODS
  A sleep laboratory of a medical unit in Japan.
  
  
  METHODS
  Seventeen patients with moderate to severe OSA and 10 control subjects were included in this study.
  
  
  METHODS
  All patients with OSA had undergone standard nocturnal polysomnography. Patients with OSA and control subjects were evaluated for IES measured by a modified Borg score, ventilation, and mouth occlusion pressure during control and inspiratory resistive loaded breathing. These tests were repeated in all patients with OSA after 2 weeks of nasal CPAP treatment.
  
  
  RESULTS
  IES to inspiratory resistive loading was lower in patients with OSA than in control subjects. There were no differences in ventilation and mouth occlusion pressure between patients and control subjects during loaded breathing. After 2 weeks of nasal CPAP, the decreased IES was increased in patients with OSA.
  
  
  CONCLUSIONS
  In patients with OSA, the decreased IES to inspiratory resistive loaded breathing is reversible with nasal CPAP. This could be one additional benefit of nasal CPAP in the treatment of OSA.
authors.affiliation: First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tun
authors.forename: W
authors.initials: W
authors.lastname: Hida
authors.forename: S
authors.initials: S
authors.lastname: Okabe
authors.forename: Y
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: H
authors.initials: H
authors.lastname: Kurosawa
authors.forename: M
authors.initials: M
authors.lastname: Tabata
authors.forename: K
authors.initials: K
authors.lastname: Shirato
mesh_terms: D000402:Airway Obstruction / Q000503:physiopathology; D000403:Airway Resistance / Q000502:physiology*; D000704:Analysis of Variance; D002245:Carbon Dioxide / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D011175:Positive-Pressure Respiration / Q000379:methods; D011312:Pressure; D012123:Pulmonary Ventilation / Q000502:physiology; D012119:Respiration; D015656:Respiratory Mechanics / Q000502:physiology*; D012677:Sensation / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000628:therapy; D013147:Spirometry
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen