Effect of absolute blood volume measurement-guided fluid management on the incidence of intradialytic hypotension-associated events: a randomised controlled trial.

Abstract

Ultrafiltration to target weight during haemodialysis is complicated by intradialytic hypotension-associated adverse events (IHAAEs) in 10-30% of dialysis treatments. IHAAEs are caused by critical reductions in absolute blood volume (ABV), due to the interaction of ultrafiltration, refill and compensatory mechanisms. Non-randomised studies have suggested that ABV-guided treatment, using an indicator dilution technique employing the blood volume monitor on the dialysis machine, could reduce the incidence of IHAAEs. We performed an open-label randomised controlled trial. Patients were randomly assigned to adjustment of target weight guided by ABV measurements or standard care. The primary outcome was the change in the incidence of IHAAEs from baseline, defined as the percentage of treatment episodes in a 4-week period where the patient had a systolic blood pressure <90mmHg or symptoms of impending hypotension. ABV measurements were compared with anthropomorphometric estimation and the gold standard using isotope dilution. A total of 56 patients were randomised, of whom 29 were allocated to ABV-guided treatment and 27 to standard care. Overall baseline incidence of IHAAEs was 26.0%. ABV-guided treatment significantly reduced the incidence of IHAAEs compared with standard care, with a mean change from baseline of -9.6% [95% confidence interval (CI) -17.3 to -1.8) versus 2.4% (95% CI -2.3-7.2). The adjusted difference between the groups was 10.5% (95% CI 1.3-19.8; P=.026). ABV measurement had moderate agreement with other methods to estimate blood volume. The sensitivity for the previously suggested threshold of a post-dialysis normalised blood volume of 65ml/kg was observed to be 74% in this study. ABV-guided volume management significantly reduced IHAAEs compared with standard care. The clinical relevance of the previously suggested threshold of 65ml/kg cannot be firmly concluded on the basis of our results. If confirmed in a larger trial, this intervention could potentially change dialysis practice and impact patient care in a clinically meaningful way.