intercellular junctions of the mesothelial cells are in charge of most transport
mechanisms. Aquaporin channels have been identified and believed to be
responsible for at least 50% of the water transport through the peritoneum. [40]
However, convection and osmotic gradient seem to play the most important roles
in water movement across the membrane since small increases of the
intraabdominal pressure during PD and small solute concentration differences
effectively move water across the peritoneum. [39]
Transport or diffusion of solutes and small proteins through the peritoneal surface
is facilitated by electric differences across the membrane and mechanisms that
may involve active transport.
Indications and contraindications of PD
PD is preferable over hemodialysis in children less than 5 kg; lack of vascular
access and contraindications to anticoagulation. [20] Contraindications to PD
include congenital defects of the abdominal wall such as gastroschisis and
omphalocele, CDH, bladder exstrophy, obliterated peritoneal cavity and
peritoneal membrane failure. [20]
Termination of PD is common after peritonitis, ultrafiltration failure, peritoneal
adhesions and renal transplantation.
Technique
- Types of PD catheters
PD catheters are made of silicone or polyurethane and have
intraperitoneal and extraperitoneal segments connected by an intramural
segment which is tunneled in the muscular layer of the abdomen. The
tunneled portion of the PD catheter has two polyester cuffs of 1 cm in
length to secure the catheter in place and help reduce bacterial
contamination of the tunnel and the peritoneal cavity.
The intraperitoneal catheter segment may be straight or coiled with