Influence of peritoneal dialysis solution on measurements of fluid status by bioimpedance spectroscopy

Purpose and methods

The accurate estimation of volume status is a central problem in dialysis patients. Recently, a bioimpedance spectroscopy (BIS) device (BCM Body Composition Monitor FMC, Germany) has attained growing interest in this regard. By processing the raw data for extracellular water (ECW) and intracellular water (ICW) by means of a validated body composition model, this device allows a quantification of the individual fluid overload (FO) compared to a representative healthy population. In this study, we addressed the issue whether the presence of peritoneal dialysate has an impact on measurements of FO by BIS in PD patients.

Results

Forty-two BIS measurements using the BCM device were performed both in the absence (D?) and presence (D+) of peritoneal dialysate in 17 stable PD patients. Data for ECW, ICW and FO (D+; D?) were analyzed by paired t test and linear regression. Mean FO was 0.99 ± 1.17 L in D? and 0.94 ± 1.27 in D+ (p = n.s. paired t test). Linear regression demonstrated an excellent degree of conformity between FO (D?) and FO (D+) (r ² = 0.93).

Conclusion

The presence of peritoneal fluid in PD patients has a negligible influence on measurements of FO by BIS. The BIS measurements can be therefore conveniently and reliably done without emptying the peritoneal cavity; this may facilitate the use of BIS in this particular group of patients.