The role of segmental bioelectrical impedance technique in the assessment of intraperitoneal ultrafiltration volume with peritoneal dialysis patients

OBJECTIVE: To investigate the role of segmental bioelectrical impedance technique (SBIA) in the assessment of intraperitoneal ultrafiltration volume with peritoneal dialysis patients. METHOD: We selected the patients at the Department of Nephrology of the First Affiliated Hospital of Zhengzhou University and measured the segmental bioelectrical impedance by a German Fresenius body composition analyzer (the Fresenius whole body composition measurement (BCM) machine was used as a segmental machine in this study). An alternating current (5 kHz, 0.05–0.7 mA) was continuously released during the measurement. The released current penetrated the peritoneal cavity on both sides of the body, from which the segmental resistance at a frequency of 5 kHz was obtained from the multifrequency data (R5/Ω). Baseline BIA measurements were initiated after the patient entered the supine position for 5–10 min, then dialysate was instilled into the peritoneal cavity. BIA measurements were performed at 10-min intervals during the retention of dialysate in the abdomen and finally ended when dialysate drainage was complete. Real-time intraperitoneal volume estimated by SBIA (IPV(SBIA))and ultrafiltration volume estimated by SBIA(UFV(SBIA)) was calculated. At the same time, the actual ultrafiltration volume at the end of peritoneal dialysis was weighed and measured (UFV(MEA)). RESULTS: A total of 30 patients were included in the study, 9 patients withdrew from the study due to subjective factors during the measurement process, and 21 patients completed the study. The correlation coefficient R(2) of UFV(SBIA) and UFV(MEA) was 0.21 (p < 0.05). Bland-Altman analysis showed that the bias of UFV(SBIA) to the actual UFV(MEA) was 0.12 L, and the 95% agreement limit was between −0.5 L and 0.74 L, which confirmed that UFV(SBIA) measured by electrical impedance method and UFV(MEA) measured by weighing method were in good agreement. The time required to reach the maximum ultrafiltration volume (UFV(SBIA)) was 108 ± 68 min, and the mean value of the maximum ultrafiltration volume (Max UFV(SBIA)) was 1.16 ± 0.60 L. CONCLUSION: The segmental bioelectrical impedance technique can be used to assess the intraperitoneal ultrafiltration volume of peritoneal dialysis patients in real-time and effectively. This method may guide the dialysis fluid retention time and the maximum ultrafiltration volume in PD patients.