Effects of cool dialysate in dialysis-related symptoms.

R. Marcen, Servicio de Nefrología, Hospital Ramon Y Cajal, Ctra Colmenar Viejo, Km 9.1, E-28034 Madrid (Spain) Dear Sir, In a previous double-blind short-term study [1], we observed the beneficial effects of cool dialysate on hemo-dialysis-induced symptoms in a group of selected patients with frequent episodes of symptomatic hypotension (SH). Later on, those results were confirmed when using cool dialysate for a 6-month period [2]. In both studies, the reduction in the percentage of symptomatic hemodialysis and in the prevalence of SH was similar. Other authors have reported indentical achievements when using a high-sodium dialysate [3–5]. Combined use of highsodium dialysate and low temperature produced the best results. Nevertheless, the beneficial effects of low temperature were greater when using low-sodium concentration dialysate, a situation prone to the development of SH [6]. In a previous article, Kerr et al. [7] pointed out that the benefit in lowering the dialysate temperature is small in relation to the placebo effect. However, the group of patients studied were not selected by the high incidence of cardiovascular instability during hemodialysis. Recently, we have evaluated 7,742 hemodialysis sessions performed in 60 patients (39 men and 21 women) during 12 months. The mean age of the patients was 51 years (range, 15–72 years) and all of them had been on dialysis for at least 1 year. Dialyses performed at 37 °C for 6 months (3,723 sessions) constituted the control period. Temperature was changed to 35 °C for the same length period (4,019 sessions) thereafter. Both temperature and conductivity were weekly checked by a sound thermistor and resistivitymeter placed at the in-line dialysis fluid. Dialysis schedule was 3–4 h, 3 times a week, using a Table 1. Incidence of SH and dialysate temperature