Large dialysate volumes are often required to increase solute clearance for peritoneal dialysis patients. The resulting increase in solute clearance might be attributable to an increased plasma-to-dialysate concentration gradient and/or to an increased effective peritoneal surface area. One of the factors affecting the latter is the peritoneal surface area in contact with dialysate (PSA-CD). The aim of this study was to estimate the change in PSA-CD after a 50% increase in the instilled dialysate volume for patients undergoing peritoneal dialysis. PSA-CD was estimated by using a method applying stereologic techniques to computed tomographic (CT) scans of the peritoneal space. The peritoneal cavity of 10 peritoneal dialysis patients was filled with a solution containing dialysate, half-isotonic saline solution, and contrast medium. Peritoneal function tests and CT scanning of the abdomen were performed twice for each patient (with an interval of 1 wk), after instillation of a 2- or 3-L solution. Scanning of thin helical CT sections was performed, and 36 random sections of the abdomen were obtained after reconstruction. A grid was superimposed on the sections. The surface area was estimated by using stereologic methods. After instillation of the 2-L solution, the volume of the peritoneal solution at the time of CT scanning was 2.32 ± 0.05 L. The PSA-CD was 0.57 ± 0.03 m2, ranging from 0.41 to 0.76 m2. The use of the 3-L solution increased the peritoneal volume by 46 ± 2%. PSA-CD increased by 18 ± 2.3% to 0.67 ± 0.04 m2 (range, 0.49 to 0.84 m2; P < 0.01). Creatinine mass transfer increased from 112 ± 10 mg to 142 ± 11 mg (P < 0.0001). The slope of the change of the plasmato-dialysate creatinine concentration gradient with time decreased from -2.26 ± 0.23 × 10-2 to -1.97 ± 0.16 × 10-2 (P = 0.01). KBD-0 (permeability-surface area product or mass area transfer coefficient at time 0 of the dwell) increased from 10.6 ± 0.7 to 13.6 ± 1.2 ml/min (P < 0.02). These data demonstrate that increasing the instilled dialysate volume by 50% for peritoneal dialysis patients results in significant increases in the PSA-CD and KBD.
|Number of pages||6|
|Journal||Journal of the American Society of Nephrology : JASN|
|State||Published - 1 Oct 2002|
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