Bicarbonate- versus lactate-based CAPD fluids: a biocompatibility study in rabbits

Previous in vitro biocompatibility studies have shown bicarbonate-based continuous ambulatory peritoneal dialysis (CAPD) fluids to be superior to those based upon lactate/acetate. To evaluate these findings in vivo, 41 rabbits were subjected to CAPD for four weeks in a randomized prospective study using either Dianeal, a commercially available dialysis fluid containing lactate, or 87b, a bicarbonate-based CAPD fluid. Ten rabbits with CAPD catheters, which were flushed with a heparin solution every 36 hours, served as controls. None of the control rabbits showed clinical or histopathological signs of peritonitis, while 8 of 20 in the Dianeal group and 6 of 21 in the 87b group contracted peritonitis. Four rabbits in the Dianeal group had to be sacrificed early due to severe peritonitis. Post mortem examinations, including scanning and light microscopy, did not reveal any macroscopic or microscopic differences among the three groups of noninfected animals. No significant distinctions between the groups could be made for body temperature, weight gain, dialysate volume, dialysate differential leukocyte count, dialysate protein content, and food intake during the course of the study. In conclusion, the present animal model did not reveal any major difference in the biocompatibility between the lactate- and the bicarbonate-based CAPD fluids.