Volume control in peritoneal dialysis patients guided by bioimpedance spectroscopy assessment

Background: Volume overload is a common problem in peritoneal dialysis patients and may contribute to the high cardiac mortality in this patient population. Controlling volume status is difficult due to the lack of appropriate and accurate assessment of dry weight. This randomized, controlled study was conducted to test if the recent use of overhydration value (OH) provided by bioimpedance spectroscopy and patients' education would help to control overhydration. Methods: 160 continuous ambulatory peritoneal patients were included in this study. All the patients were randomly allocated to 2 groups: in Group 1 the patients and their primary nurses were informed of the OH values provided by bioimpedance spectroscopy whereas in Group 2 the values were not revealed and patients' volume was measured by the standard methods. Fluid status was evaluated by means of repeated bioimpedance analysis and clinical assessment. Urine volume, blood pressure and use of antihypertensive medications were recorded. Results: There were no differences in gender, age, diabetes, height, weight and clinical hydration status between the 2 groups at the baseline. In Group 1, OH (p < 0.05), extracellular volume and the extracellular volume to intracellular volume ratio decreased steadily during the 3-month follow-up. On the contrary, all 3 parameters increased significantly in Group 2. SBP decreased significantly in Group 1 but increased significantly in Group 2. Conclusion: Our study shows that the use of OH as determined by bioimpedance spectroscopy may facilitate volume control in peritoneal dialysis patients.