Continuous positive airway pressure in severe obstructive sleep apnea reduces pain sensitivity.
STUDY OBJECTIVE
To evaluate effects of CPAP on pain sensitivity in severe OSA patients.


DESIGN
Within-subject treatment study.


SETTING
Hospital-based sleep disorders center.


PATIENTS
Twelve severe OSA patients (7 men, 5 women), 50.2 ± 12.5 years, with no pain.


INTERVENTIONS
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).


CONCLUSION
CPAP treatment reduces pain sensitivity in OSA patients. Future studies will focus on patients with OSA and chronic pain and identify mediating mechanisms.
['Khalid|Imran|I|', 'Roehrs|Timothy A|TA|', 'Hudgel|David W|DW|', 'Roth|Thomas|T|']
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 D017286:Polysomnography D020181:Sleep Apnea, Obstructive D055815:Young Adult
Pain sensitivity CPAP treatment obstructive sleep apnea syndrome