Assessment of body fluid status in hemodialysis patients using the body composition monitor measurement technique.

AIMS AND OBJECTIVES: The main objective of the study was to correlate the target dry weight in haemodialysis (HD) patients as assessed clinically by nephrologists to those measured by the Body Composition Monitor (BCM - Fresenius) machine. The second objective was to compare pre and postdialysis changes of extracellular fluid and clinical parameters.

BACKGROUND: Clinical assessment of target dry weight in HD patients remains problematic. Inaccurate dry weight resulted in hypovolaemic or overhydration states. The BCM (Fresenius) utilises bioimpedance technology for body fluid monitoring and has been extensively validated.

DESIGN: This was a prospective cross-sectional study on consecutive patients who underwent HD and gave informed consent. Methods.  The target dry weights of these patients were first assessed by their attending nephrologists and appropriate ultrafiltration prescribed. Their body fluid statuses were then measured with the BCM before and after HD treatment.

RESULTS: Eighty HD patients (37 men, 43 women) with a mean age of 55 ± 13 years and a mean duration on HD of 71 ± 56 months were studied. The dry weight measured by BCM significantly correlated with dry weight assessed by the nephrologists. The mean dry weight was higher when assessed by the nephrologists compared to that by BCM. Only systolic blood pressure and not other components of blood pressure reduced after HD treatments.

CONCLUSION: The BCM is a rapid and easy-to-use tool that can help HD nursing staffs to adjust patients' dry weights between nephrologists' reviews thus optimising HD therapy and patient outcomes.

RELEVANCE TO CLINICAL PRACTICE: We propose that experienced HD nursing staff be trained in the use of the BCM or other simple bioimpedance machines to help monitor patient overhydration and approximate dry weight in consultation with the nephrologists responsible for the care of these patients so as to obviate excessive residual overhydration between nephrology reviews.