Hemocontrol and Blood Pressure Control in Dialysis Patients

Overview

Volume overload contributes significantly to the pathogenesis of hypertension in hemodialysis patients. The Hemocontrol(HC)system (Gambro), which automatically adjusts ultrafiltration rate and dialysate conductivity according to blood volume variations during dialysis, has been suggested to improve hemodynamic tolerance and thus facilitate fluid removal. This randomized controlled trial was designed to compare the use of HC with standard hemodialysis to test the hypothesis that the use of the HC system may lower home blood pressure in comparison with standard hemodialysis as a primary endpoint. Secondary endpoints are a variation in the percentage of dialysis sessions requiring nurses' interventions for intra-dialytic hypotension and a change in the health-related quality of life of HD patients.

Hypertension is a common problem in patients undergoing chronic maintenance hemodialysis (HD) with a reported prevalence of 50 to 90 % \[Hörl, 2002\]. As a major risk factor for cardiovascular disease, hypertension contributes to the high rate of morbidity and mortality in ESRD patients \[Foley, 1996; Port, 1999\]. For a majority of dialysis patients, volume overload (VO) plays a major role in the pathogenesis of hypertension \[Fishbane, 1996; Rahman, 2000; Ventura, 1997\] and removing excess volume can often normalize blood pressure \[Fishbane, 1996\]. Unfortunately, correcting VO frequently proves to be difficult because of hemodynamic instability during HD sessions. As much as 20 to 50% of dialysis patients present with symptoms of intradialytic hypotension (IDH) \[Santoro, 2002\]. IDH increases nursing work load and negatively affects the efficacy of dialysis and the quality of life of HD patients. Different measures are used to avoid IDH, such as limitation of salt and water intake, avoidance of antihypertensive medication before dialysis, utilization of low temperature dialysate, and modeling of ultrafiltration and/or dialysate conductivity. These measures often generate mixed results. The Hemocontrol (HC) biofeedback system (Gambro®) has been reported to reduce hemodynamic instability and hypotensive episodes during hemodialysis \[Basile, 2001; Begin, 2002; Ronco, 2000; Santoro, 1994; Santoro, 1998; Santoro, 2002; Wolkotte, 2002\]. The HC system consists in a fully integrated biofeedback system that monitors and regulates blood volume contraction during hemodialysis through software-driven adjustments of ultrafiltration rate and dialysate conductivity. By improving hemodynamic tolerance during dialysis, the use of the HC system has been suggested to facilitate fluid removal and correction of VO, leading to improved control of hypertension. The present randomized controlled trial was designed to test the hypothesis that the use of the HC system would lower home BP in comparison with standard hemodialysis as a primary endpoint. Secondary endpoints are a variation in the percentage of HD sessions requiring nurses' interventions and a change in the health-related quality of life of HD patients.