11 / 21
Nursing Education 2018
Journal of Nursing and Health Studies
ISSN: 2574-2825
Page 63
April 23-25, 2018
Rome, Italy
27
th
Edition of World Congress on
Nursing Education &
Research
R
emoval of uremic waste products and excess of accumulated
body fluid are the goals of peritoneal dialysis (PD) in the
treatment of patients with chronic renal failure. The peritoneum
used as a dialysis membrane consists of the mesothelial layer
and interstitial tissue, in which blood- and lymphatic vessels are
present. The microvessels allow transport of solutes and water
from the blood to the dialysis fluid in the peritoneal cavity. Solutes
like urea are transported by diffusion across the vascular wall;
fluid removal (ultrafiltration) requires a pressure gradient. The
latter consists of the intravascular hydrostatic pressure, which
drives fluid out of the microvessels to the interstitium through
interendothelial pores, but also of an osmotic pressure gradient.
The latter is created by adding high dosages of glucose to the
dialysis fluid.This is only effective, because the transcellular water
channel aquaporin-1 (AQP-1) is present in peritoneal endothelial
cells. AQP-1 is permeable towater only, not to solutes like glucose
and Na+. Consequently AQP-1 allows free water (water only)
transport (FWT). The osmotic gradient contributes to SPFT to a
limited extent only. During the first few years of PD about 40% of
the ultrafiltered volume consists of FWT and 60% of small-pore
fluid transport (SPFT). Loss of ultrafiltration capacity occurs
especially in long-term PD patients. It is mostly associated with
high solute transport rates, suggestive of an enlarged vascular
surface area leading to rapid disappearance of the osmotic
gradient. This affects especially SPFT. A longitudinal study
showed a marked reduction of SPFT after 4 years of PD, possibly
due to vascular abnormalities. FWT is markedly decreased in
patients who develop encapsulating peritoneal sclerosis. Binding
of free water by a collagen increase is the most likely explanation.
Determination of both SPFT and FWT are essential in the follow-
up of PD patients.
r.t.krediet@amc.uva.nlFluid removal in peritoneal dialysis
Raymond T Krediet
Academic Medical Centre, Netherlands
J Nurs Health Stud 2018, Volume 3
DOI: 10.21767/2574-2825-C1-003