title: Continuous positive airway pressure in severe obstructive sleep apnea reduces pain sensitivity.
abstract: OBJECTIVE
  To evaluate effects of CPAP on pain sensitivity in severe OSA patients.
  
  
  METHODS
  Within-subject treatment study.
  
  
  METHODS
  Hospital-based sleep disorders center.
  
  
  METHODS
  Twelve severe OSA patients (7 men, 5 women), 50.2 ± 12.5 years, with no pain.
  
  
  METHODS
  The morning after a diagnostic nocturnal polysomnogram (NPSG), patients underwent a training session of finger withdrawal latency (FWL) testing to a radiant heat stimulus, a validated human behavioral model of thermal nociception. Baseline FWL in seconds was obtained after the training session. CPAP pressure was titrated on a second night in the laboratory. Two nights after titration, patients returned to sleep in the laboratory on CPAP. FWL was tested in the morning after awakening, after 6-8 wks of CPAP use, and finally (within 6-8 weeks) after 2 nights of discontinuation of CPAP. Mean FWL in seconds (sec) was compared using MANOVAs with nights as the within subject variable.
  
  
  RESULTS
  Apnea-hypopnea index (AHI) decreased from 50.9 ± 14.5 to 1.4 ± 1.0 with CPAP, and sleep continuity improved. In parallel, FWL increased significantly from a mean baseline of 9.8 ± 1.3 sec to 13.7 ± 5.1 sec (P = 0.01) and with continued CPAP use (5.1 ± 2.3 h nightly) for 6-8 weeks FWL remained elevated (21.1 ± 16.2 sec). After the 2-night CPAP discontinuation, apnea/hypopneas returned and sleep was fragmented (AHI = 32.6 ± 19.8). FWL decreased to 11.6 ± 5.9 sec relative to intermediate-term CPAP use (P = 0.03).
  
  
  CONCLUSIONS
  CPAP treatment reduces pain sensitivity in OSA patients. Future studies will focus on patients with OSA and chronic pain and identify mediating mechanisms.
authors: King Faisal Specialist Hospital & Research Center, Jeddah, Saudi Arabia.
authors: Imran
authors: I
authors: Khalid
authors: Timothy A
authors: TA
authors: Roehrs
authors: David W
authors: DW
authors: Hudgel
authors: Thomas
authors: T
authors: Roth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology / Q000628:therapy*; D055815:Young Adult