Body composition monitoring to manage fluid status in haemodialysis

Haemodialysis patients with little or no urine output usually experience periods of overhydration as they accumulate fluid between treatments through intake of salt and water. Many are also dehydrated when fluid is removed during dialysis. The time-averaged deviation from normal hydration will depend on the patient's fluid status after dialysis and his or her interdialytic fluid gains. Attempts to minimise the adverse effects of abnormal hydration begin by setting patients' ‘target’ weight to optimise their post-dialysis fluid status. However, the clinical indicators that are traditionally used to adjust target weight can be ambiguous or misleading. Body composition monitoring using multifrequency bioimpedance measurements can now provide an objective assessment of fluid status. The measurements are non-invasive and can be made in a few minutes before or after dialysis. If added to the complete clinical picture, this technology can improve outcomes and quality of life for patients.