Assessment of fluid status in CAPD patients using the body composition monitor

Abstract

Aims and objectives: To assess the degree of overhydration in our peritoneal dialysis patients and to examine the factors contributing to overhydration.

Background: Volume control is critical for the success of peritoneal dialysis, but dry weight has been difficult to ascertain accurately. Chronic fluid overload and hypertension are among the leading causes of mortality in dialysis patients.

Design: A cross-sectional observational study.

Methods: The body composition monitor (Fresenius Medical Care, Bad Homburg, Germany) is a bioimpedance spectroscopy device that has been validated for the assessment of overhydration. We used this body composition monitor device on all patients on continuous ambulatory peritoneal dialysis at our institution who met the inclusion criteria to assess their degree of overhydration.

Results: Thirty four (17 men, 17 women; mean age 44·5 ± 14·2 years) of a 45 continuous ambulatory peritoneal dialysis patients were enrolled. The mean overhydration was 2·4 ± 2·4 l. Fifty per cent of the patients were ≥2 l overhydrated. Overhydration correlated with male gender, low serum albumin, increasing number of antihypertensive agents and duration of dialysis. There was no difference in overhydration between diabetic and non-diabetic patients. Men were more overhydrated than women, had lower Kt/V and were older. Although, there was no difference in blood pressure between the genders, men had a trend towards a higher usage of antihypertensive agents.

Conclusion: Our study demonstrates that overhydration is common in peritoneal dialysis patients. Blood pressure should ideally be controlled with adherence to dry weight and low salt intake rather than adding antihypertensive agents even in the absence of clinical oedema.

Relevance to clinical practice: Body composition monitor is a simple, reliable and inexpensive tool that can be routinely used in the outpatient clinic setting or home visit to adjust the dry weight and avoid chronic fluid overload in between nephrologists review.