Document Detail


Lymphatic versus nonlymphatic fluid absorption from the peritoneal cavity as related to the peritoneal ultrafiltration capacity and sieving properties.
MedLine Citation:
PMID:  1308683     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In this article we discuss the role of capillary fluid absorption via Starling mechanisms (the transcapillary hydrostatic pressure gradient opposed by the colloid osmotic pressure gradient as multiplied by the capillary UF coefficient) vs. lymphatic fluid absorption as determinants of the total fluid loss from the peritoneal cavity during continuous ambulatory peritoneal dialysis (CAPD). We also mention that, under nonsteady state conditions, there is in addition some net absorption of fluid into the interstitium of tissues surrounding the peritoneal cavity. Support for the contention that nonlymphatic fluid absorption directly into the capillaries is the major mode of fluid transport from the peritoneal cavity to the blood is given by measurements of the peritoneal-to-blood clearance of tracer albumin (or other proteins). Such measurements yield clearance values of the order of 0.2-0.3 ml/min in CAPD. This represents only about 20% of the total peritoneal fluid loss rate (1.2-1.3 ml/min) in ordinary CAPD dwells. Indirect support for a relatively low lymph flow is also derived from capillary physiology. Like continuous capillary walls, the peritoneal membrane shows a bimodal selectivity towards molecules of graded molecular size. Thus, small solute transport can be described as occurring by diffusion through numerous 'small' (approximately 50 A radius) pores, whereas large solute transport is consistent with blood-peritoneal convection through smaller numbers of 'large' (radius approximately 250 A) pores. Furthermore, peritoneal sieving data are compatible with the notion that large crystalloid osmotic pressure gradients cause fluid flow through a water-exclusive ('ultra-small' pore) pathway. A three-pore model of peritoneal selectivity can explain why small solute sieving coefficients are only 0.5-0.6, even though small solute reflection coefficients are close to zero. Another important implication of the three-pore concept is that the peritoneal UF-coefficient is much higher than previously thought, emphasizing the role of capillary absorption in the fluid loss from the peritoneal cavity in CAPD. It is concluded that fluid loss from the peritoneal cavity is dominated by capillary fluid absorption. Hence, lymphatic absorption accounts for just a small fraction of the peritoneal-to-blood absorption of fluid in peritoneal dialysis.
Authors:
B Rippe; E R Zakaria
Related Documents :
6723043 - Simplified determination of carboxyhemoglobin.
1760713 - Effects of different lipid emulsions on lymphocyte function during total parenteral nut...
15817503 - Water channels (aquaporins) and their role for postnatal adaptation.
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Blood purification     Volume:  10     ISSN:  0253-5068     ISO Abbreviation:  Blood Purif.     Publication Date:  1992  
Date Detail:
Created Date:  1993-10-14     Completed Date:  1993-10-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8402040     Medline TA:  Blood Purif     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  189-202     Citation Subset:  IM; S    
Affiliation:
Department of Nephrology, University Hospital, Lund, Sweden.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Absorption
Animals
Ascitic Fluid / metabolism*
Capillaries / ultrastructure
Cats
Humans
Lymphatic System / physiology*
Peritoneal Cavity / blood supply,  physiology*
Peritoneal Dialysis, Continuous Ambulatory
Porosity
Rats
Ultrafiltration

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Role of lymphatics in peritoneal dialysis.
Next Document:  Intraperitoneal fluid fluxes analyzed according to the 'three-pore' model in individual patients on ...