EFFECTS OF CONTROLLED BLOOD COOLING ON HEMODYNAMIC STABILITY AND UREAKINETICS DURING HIGH-EFFICIENCY HEMODIALYSIS

Although the use of cooled dialysate during hemodialysis is associated with stabilization of intradialytic BP, the effects of blood cooling on hemodynamics and urea kinetics in high-efficiency hemodialysis have not been completely studied. In particular, the effects of blood cool ing have not been elucidated in very short-time, high K/V dialysis tre atments, in which postdialysis urea rebound is maximized. In theory, b lood cooling could increase urea compartmentalization during treatment and decrease dialysis efficacy. Measurements of cardiovascular hemody namics and urea kinetics were performed in 15 patients (56 studies) du ring dialysis, using a blood temperature monitor with control of dialy sate temperature. Dialysate temperature was adjusted to either lower t he core temperature or raise the core temperature by, respectively, pr oducing neg ative heat-energy exchange (cooled dialysis) or keeping he at-energy exchange in the extracorporeal circuit neutral (thermoneutra l dialysis) so that energy was not transferred to or from the patient. Each subject was studied on both protocols, thereby allowing each ind ividual to act as his own control. Tn cooled dialysis, heat-energy exc hange in the extracorporeal circuit was -266 +/- 15 kJ per treatment, and dialysate temperature averaged 35.7 +/- 0.02 degrees C, In thermon eutral dialysis, heat-energy exchange in the extracorporeal circuit av eraged 5 +/- 31 kJ per treatment, and dialysate temperature averaged 3 7.1 +/- 0.02 degrees C, Dialysate cooling resulted in a reduction in m ean body temperature compared with thermoneutral therapy (-0.22 +/- 0. 04 versus +0.31 +/- 0.05 degrees C). Cooling resulted in a greater inc rease in peripheral vascular resistance index (+515 +/- 160 versus +11 4 +/- 92 dyn.sec/cm(5) per m(2)), an increase in mean arterial pressur e (+4 +/- 3 versus -4 +/- 4 mmHg), a reduction in the maximum intradia lytic fall in mean arterial pressure (-10 +/- 2 versus -18 +/- 3, mmHg ), and a reduction in staff interventions for hypotension or dialytic symptoms (6 of 28 versus 12 of 28 studies). These differences occurred without differences in the change in blood volume (-14.3 +/- 1.8% ver sus -13.9 +/- 2.2%) or cardiac index (-0.4 +/- 0.1 versus -0.4 +/- 0.2 , L/min per m(2)). Urea rebound (37 +/- 4% versus 38 +/- 3%) and effec tive Kt/V (1.29 +/- 0.05 versus 1.32 +/- 0.06) were not different betw een groups. Thus, body temperature cooling can be used to stabilize BP and reduce intradialytic events requiring staff intervention without compromising the efficacy of treatment in high-efficiency dialysis.