Sleep apnea is a common condition where breathing repeatedly stops and starts during sleep. It is especially common in patients with end-stage renal disease (ESRD), affecting up to half of these individuals. Researchers at TRI, led by Senior Scientist Dr. T Douglas Bradley, have hypothesized that fluid buildup in the body, as well as a shift in fluid from the legs towards the head at night, could contribute to sleep apnea severity.
Patients with ESRD regularly undergo dialysis to manage blood urea levels as well as fluid buildup, and those receiving overnight dialysis often have a reduction in sleep apnea severity. To test the role of fluid buildup in the causation of sleep apnea, Dr. Bradley and colleagues used a method known as ultrafiltration to remove excess fluid without performing hemodialysis. Ultrafiltration was carried out on 15 patients with ESRD on a non-dialysis day.
"Fluid removal by ultrafiltration was accompanied by remarkable improvements in sleep quality and a reduction of sleep apnea symptoms," Dr. Bradley says of the study results. "We found that the degree of improvement in patients was related to the degree of fluid volume reduction during ultrafiltration. These findings are important for our understanding of sleep apnea, highlighting the role of fluid overload in the development of sleep apnea, and also the ability to target fluid buildup for potential treatments, especially in patients with ESRD."
This work was supported by the Canadian Institutes of Health Research, Mitacs, the Canadian Thoracic Society, the European Respiratory Society, the Joseph M. West Family Memorial Fund and the Toronto Rehabilitation Institute. CT Chan holds the R. Fraser Elliot Chair in Home Dialysis and [no-lexicon]TD[/no-lexicon] Bradley holds the Clifford Nordal Chair in Sleep Apnea and Rehabilitation Research.
Effect of ultrafiltration on sleep apnea and sleep structure in patients with end-stage renal disease. Lyons OD, Chan CT, Yadollahi A, Bradley TD. American Journal of Respiratory and Critical Care Medicine. 2015 Jun 1. [Pubmed abstract]