Bioimpedance Spectroscopy-Guided Ultrafiltration Normalizes Hydration and Reduces Intradialytic Adverse Events in Hemodialysis Patients.

Abstract

Chronic fluid overload as well as excessive fluid removal are associated with increased morbidity and mortality in hemodialysis (HD) patients. The clinical method to probe the dry weight is often inaccurate and the bioimpedance spectroscopy (BIS) is shown to improve the accuracy. We compared the impact of BIS and clinical methods to guide ultrafiltration (UF) in a randomized controlled study on the intradialytic complications and blood pressure control in prevalent HD patients. Fifty patients on maintenance HD were randomized to BIS method (BIS-group) and clinical method (CL-group) to guide UF. The body composition monitor (BCM) was done post-HD in all patients at baseline and 2-weeks interval during the study period of 6 months to determine the hydration status, but the result was revealed only to the nephrologist managing the patients in BIS-group to probe the dry weight. The endpoints of the study were blood pressure control, intradialytic complications and anti-hypertensive drug burden. The mean age was 56.0 ± 12.0 years and 70% were male. There was significant increase in patients with normal hydration in BIS-group (20% vs. 88%, p = 0.0001), but remained similar to baseline in CL-group (40% vs. 48%, p = 0.3) at 6 months. The incidence of intradialytic hypotension was significantly reduced in BIS-group (4.84 ± 3.0 vs. 2.8 ± 3.13 events/patient/6 months, p = 0.003). There was 35% reduction in hypertensive pill burden in BIS-group with similar blood pressure, compared to CL-group. Post-dialysis underhydration was more common than over or normal hydration at baseline in our population, indicating that clinical method to probe dry weight often resulted in hypovolemia. BIS method to determine dry weight resulted in normalization in volume status and consequently resulted in significant reduction in intradialytic hypotension and anti-hypertensive pill burden over 6-month period.