Spatial Distribution of Dialysate in Patients and its Implications to Intradialysate Diffusion
| Autor: | John Burke, Anthony C. LaMont, Brian Hills, Seamus Birch |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
medicine.medical_specialty
business.industry medicine.medical_treatment Continuous ambulatory peritoneal dialysis 030232 urology & nephrology Urology General Medicine Surgery Peritoneal dialysis 03 medical and health sciences 0302 clinical medicine Nephrology Ambulatory medicine In patient 030212 general & internal medicine Diffusion (business) Dialisis peritoneal business |
| Zdroj: | Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis. 22:698-704 |
| ISSN: | 1718-4304 0896-8608 |
| DOI: | 10.1177/089686080202200609 |
| Popis: | ObjectiveTo visualize and quantify the spatial distribution of dialysate in patients on continuous ambulatory peritoneal dialysis (CAPD) and, hence, estimate diffusion times for fluid “pockets” wherever intradialysate concentration gradients may not be dissipated by convective currents.DesignContrast medium was added to the dialysate of three supine CAPD patients before an exchange prior to computed tomographic (CT) scanning. Spatial information in the CT scanner was then downloaded to other computers and processed to produce impressive three-dimensional models of dialysate distribution using “wire frame technology.”ResultsModels differed between patients but all demonstrated pooling of dialysate in the paracolic gutters, subphrenic space, and, especially, in the pelvic cavity. Some pockets of fluid were almost isolated. Quantitatively, the models can account for over 80% of the volume of the exchange (2.5 L), displaying an effective area of contact of 913 – 1450 cm2between parietal peritoneum and dialysate. This amounts to only 11% – 21% of the anatomic area, again emphasizing the uneven distribution of dialysate. Ignoring very thin (< 0.1 mm) films of dialysate, the bulk (80%) had mean thicknesses ranging from 1.6 to 1.9 cm. Transcendental equations for bulk diffusion were then applied to these findings to determine a theoretical time for urea of about 2 – 3 hours to half-saturation, or 5 – 7 hours to 80% saturation, in the absence of convective currents.ConclusionsThe distribution of dialysate within the peritoneal cavity is very uneven, resulting in long diffusion times in fluid pockets wherever convective currents may be minimal. Hence, intradialysate diffusion should not be ignored when modeling peritoneal dialysis. |
| Databáze: | OpenAIRE |
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