Many reports note that the use of cool dialysate has a protective effect on blood pressure during hemodialysis (HD) treatments. However, formal clinical trials in which dialysate temperature is tailored to the body temperature of appropriately selected hypotension-prone patients are lacking. We investigated the effect of thermal control of dialysate on hemodynamic stability in hypotension-prone patients selected from 27 centers in nine European countries. Patients were eligible for the study if they had symptomatic hypotensive episodes in 25% or more of their HD sessions, assessed during a prospective screening phase over 1 month. The study is designed as a randomized crossover trial with two phases and two treatment arms, each phase lasting 4 weeks. We used a device allowing the regulation of thermal balance (Blood Temperature Monitor; Fresenius Medical Care, Bad Homberg, Germany), by which we compared a procedure aimed at preventing any transfer of thermal energy between dialysate and extracorporeal blood (thermoneutral dialysis) with a procedure aimed at keeping body temperature unchanged (isothermic dialysis). One hundred sixteen HD patients were enrolled, and 95 patients completed the study. During thermoneutral dialysis (energy flow rate: DeltaE = -0.22 +/- 0.29 kJ/kg x h), 6 of 12 treatments (median) were complicated by hypotension, whereas during isothermic dialysis (energy flow rate: DeltaE = -0.90 +/- 0.35 kJ/kg x h), the median decreased to 3 of 12 treatments (P < 0.001). Systolic and diastolic blood pressures and heart rate were more stable during the latter procedure. Isothermic dialysis was well tolerated by patients. Results show that active control of body temperature can significantly improve intradialytic tolerance in hypotension-prone patients. Copyright 2002 by the National Kidney Foundation, Inc.
