Recruiting people for with undiscovered or untreated obstructive sleep apnea for clinical trials is tedious and expensive. Stopping CPAP on study subjects with severe OSA might be unethical due to increased cardiovascular risk … but would it? What if (researchers asked) we just stopped it for a tiny little while? Then, like, studied them really quick and put them back on CPAP before their blood vessels noticed the difference? There would suddenly be a huge population of potential research subjects.
That’s the premise of this pilot study by Kohler et al, who randomized 41 OSA patients to continue or stop CPAP for 2 weeks. Those who stopped had abrupt return of OSA with daytime somnolence (Epworth up by 2.7), worse endothelial function (flow-mediated dilation), higher systolic blood pressure (by 8 mm Hg) and heart rate (by 6 beats). Measured psychomotor performance (driving simulator & vigilance tests), inflammatory markers, insulin sensitivity and lipids did not change in 2 weeks. They pronounce this method safe and propose temporarily stopping CPAP on people with OSA to enroll them into trials of short duration.
Kohler M et al. The effects of CPAP therapy withdrawal in patients with obstructive sleep apnea: a randomised controlled trial. Am J Respir Crit Care Med 2011; 184:1192-1199.