Chapter 93 Peritoneal Dialysis
Peritoneal dialysis (PD) removes toxic substances, body wastes, and excess fluids using the peritoneum (a semipermeable membrane) as an exchange surface. Solutes move from the bloodstream into the peritoneum and then into the dialysate. This occurs through diffusion (movement from an area of higher concentration to one of lower concentration). The dialysate is a hypertonic dextrose solution with a concentration similar to plasma. A higher percentage of dextrose will lead to a greater osmotic effect and more fluid removal.
The PD catheter is placed through a small abdominal incision or through a trocar-induced puncture hole into the peritoneal cavity. This catheter is connected to a system of fluid bags and tubing. A PD exchange consists of three steps: (1) filling (fluid flows into the abdomen), (2) dwell or equilibrium time (fluid remains in the abdomen), and (3) drain (fluid flows out of the abdomen). The “fill” bag is raised above the patient. Opening the clamp allows fluid to flow into the abdomen (approximately 10 minutes). During the dwell time, equilibration between plasma and dialysis fluid leads to removal of solutes and excess fluid. Typically, this ranges from 15 to 60 minutes, but it can last several hours depending on the type of PD. After the prescribed dwell or equilibrium time, the “drain” bag is placed below the patient to enable gravity drainage of the PD fluid (approximately 10 minutes). Fill and drain times will be affected by patency of the catheter, height of the fluid bags, patient position, and other factors. The type of dialysate, equilibrium times, and number of exchanges per day will be prescribed. It is important to maintain an accurate record of the exact amount of fluid instilled and drained.
PD is an alternative to hemodialysis in the treatment of acute and chronic renal failure in children. PD may be contraindicated for use or used with extreme caution with the following conditions:
• Abdominal defects that prevent effective PD or have an increased risk of infection (e.g., diaphragmatic hernia, omphalocele, gastroschisis, bladder extrophy, irreparable hernia)
• Extensive abdominal adhesions or loss of peritoneal functioning may lead to difficulty with catheter flow and effectiveness of PD.
• Body size limitation of either too small or too large. The abdominal cavity may be too small and/or unable to tolerate dialysate volume. Morbid obesity may also cause issues related to healing, effectiveness of treatment, and/or increased caloric absorption from dextrose in dialysate.
• Inflammatory or ischemic bowel disease (e.g., necrotizing enterocolitis, frequent episodes of diverticulitis) may lead to exacerbation of infection.
• Abdominal wall or skin infection may lead to contamination during catheter placement.
• Recent placement of an intraabdominal foreign body (e.g., ventricular-peritoneal shunt) may lead to leakage and/or peritonitis. Adequate healing time is needed.
• Severe malnutrition may be associated with problems with wound healing and/or peritoneal protein loss.
• Inability to tolerate PD volumes and/or inability to achieve desired clearance leads to the need for alternative methods of dialysis.
• Frequent peritonitis or other PD-related complications may warrant switching to hemodialysis.
NURSING ASSESSMENT
1. Assess the child’s underlying condition including medical diagnosis and conditions that PD may be contraindicated, fluid and electrolyte status, hemodynamic stability, body weight, and other related factors.
2. Assess the child’s ability to tolerate the procedure and therapy.
3. Assess the child’s response to therapy and the resolving of symptoms or improvement in underlying condition.
