Use of dextran 70 to estimate peritoneal lymphatic absorption rate in CAPD

Peritoneal lymphatic absorption rate (LAR) in 15 patients on a CAPD program was measured by estimation of the disappearance of dextran 70 from the peritoneal cavity. The LAR was 1.03 +/- 0.45 ml/min. The cumulative lymphatic absorption, cumulative net transcapillary ultrafiltration, calculated net ultrafiltration (CUF) and measured net ultrafiltration (MUF) at 4 h exchange were respectively: 261 +/- 127 ml, 694 +/- 134 ml, 446 +/- 135 ml and 409 +/- 136 ml. Calculated and measured net ultrafiltration didn't differ significantly. An inverse correlation between MUF and LAR and a positive correlation between MUF and the ratio for dialysate glucose concentration at 4 hand dialysate glucose at 0 h (G4/G0) were observed (r = -0.522 and 0.547, respectively, p < 0.05). The multiple correlation coefficient between the MUF and LAR plus G4/G0 was higher (r = 0.617, p < 0.05). Peritonitis and the presence of diabetes didn't interfere with LAR. We have concluded that lymphatic absorption plus peritoneal transfer rate of glucose are important determinants of intraperitoneal volumes and that dextran 70 is a useful marker to measure lymphatic absorption.