title: Effect of increased dialysate volume on peritoneal surface area among peritoneal dialysis patients.
abstract: 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 m(2), ranging from 0.41 to 0.76 m(2). 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 m(2) (range, 0.49 to 0.84 m(2); 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 plasma-to-dialysate creatinine concentration gradient with time decreased from -2.26 +/- 0.23 x 10(-2) to -1.97 +/- 0.16 x 10(-2) (P = 0.01). K(BD-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 K(BD).
authors.affiliation: Department of Nephrology, Rabin Medical Center-Golda Campus, Tel Aviv University Medical School, Petah Tikva, Israel. uzig@clalit.org.il
authors.forename: Avry
authors.initials: A
authors.lastname: Chagnac
authors.forename: Pearl
authors.initials: P
authors.lastname: Herskovitz
authors.forename: Yaacov
authors.initials: Y
authors.lastname: Ori
authors.forename: Tali
authors.initials: T
authors.lastname: Weinstein
authors.forename: Judith
authors.initials: J
authors.lastname: Hirsh
authors.forename: Miriam
authors.initials: M
authors.lastname: Katz
authors.forename: Uzi
authors.initials: U
authors.lastname: Gafter
mesh_terms: D000328:Adult; D000368:Aged; D003404:Creatinine / Q000032:analysis / Q000378:metabolism; D015314:Dialysis Solutions / Q000008:administration & dosage* / Q000737:chemistry; D004058:Diffusion; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis; D010537:Peritoneum / Q000378:metabolism*
chemical_list: D015314:Dialysis Solutions; D003404:Creatinine