Short-Term Effects of Intradialytic Hypoxemia on Plasma Markers of Hypoxia

Short episodes of intradialytic hypoxemia (IDH) are a common but still under-recognized complication of hemodialysis with clinically significant consequences. The aim of the study was to analyze the effect of IDH on the secretion of hypoxia-inducible factors 1 and 2 and sirtuin 1. The study group consisted of 49 chronic hemodialysis patients, mean age 58.8 ± 15.3 years. Pulse oximetry was continuously recorded throughout hemodialysis. Blood was collected three times during a single mid-week hemodialysis session and at the start of the next mid-week session to assess levels of sirtuin 1 (SIRT1), hypoxia-inducible factor 1 (HIF-1), and hypoxia-inducible factor 2 (HIF-2). IDH, defined as a decrease in blood oxygen saturation below 90%, occurred in 22 (45%) patients. The mean time of hypoxemia during dialysis was 0.52% of the total hemodialysis session time. Plasma SIRT1 and HIF-2 concentrations did not change significantly during hemodialysis, whereas plasma HIF-1 levels decreased significantly. Multiple regression analysis showed that pre-dialysis plasma SIRT1 and HIF-1 explained a significant portion of the variability of blood oxygen saturation during hemodialysis. Pre-dialysis plasma levels of sirtuin 1 and HIF-1 could be considered predictors of the decline in blood oxygen saturation during hemodialysis sessions; they also determine the degree of variability of this parameter during the procedure.