EXTRACELLULAR FLUID VOLUME DETERMINED BY BIOELECTRIC IMPEDANCE AND SERUM-ALBUMIN IN CAPD PATIENTS

Aim. To investigate the relationship between serum albumin and extrace llular fluid volume, as measured by multifrequency bioelectrical imped ance, in stable patients treated by CAPD. Method. Fifty-nine stable CA PD patients were assessed. Serum albumin (bromocresol green) and CRP, age, dialysate to plasma (D/P) creatinine ratio, normalized protein ca tabolic rate (nPCR), daily urine and peritoneal protein losses, and ex tracellular fluid volume (Vecf) were measured in each patient. Vecf wa s calculated as a percentage of actual body weight (Vecf% ABW), of lea n body mass derived from anthropometry (Vecf% LBM) and of total body w ater (Vecf% Vtbw). Comparisons between those with a normal serum album in (greater than or equal to 37 g/l) and those with a low serum ajbumi n (< 37 g/l) were made by Mann-Whitney U test. Correlations with serum albumin were sought by Pearson's test. Results. The D/P creatinine ra tio, daily peritoneal and urine protein losses, and extracellular flui d volume (Vecf% LBM and Vecf% Vtbw) were all significantly greater in patients with serum albumin < 37 g/l as compared to those greater than or equal to 37 g/l; P < 0.05. Age, CRP, and nPCR were not different. Serum albumin was negatively correlated with Vecf% LBM, r = -0.25; P = 0.05, Vecf% Vtbw, r = -0.39; P = 0.002, and daily urinary albumin los s, I = -0.25, P = 0.06. Conclusion. Hypoalbuminaemia is partly depende nt on subclinical overhydration in CAPD patients. Serum albumin is neg atively correlated with increased extracellular fluid volume and the p roportion of Vecf to Vtbw is increased in hypoalbuminaemic patients. M ultifrequency bioelectrical impedance is able to identify these abnorm alities.