Peritoneal Dialysis II: Peritoneal Dialysis Systems and Complications

Three primary methods exist: Acute Intermittent Peritoneal Dialysis (AIPD) for emergencies with dwell times of 30 minutes to 2 hours, Continuous Ambulatory Peritoneal Dialysis (CAPD) requiring four manual daily exchanges with 4-6 hour dwell times, and Automated Peritoneal Dialysis (APD) using a machine for four or more nightly exchanges. Each method offers different benefits for managing solute and fluid removal based on patient stability and lifestyle needs.

AIPD causes more gradual fluid shifts compared to hemodialysis, making it safer for unstable patients. Although less efficient at removing solutes and fluids, its gentler approach prevents sudden hemodynamic changes. This makes AIPD ideal for emergency situations involving uremia, acidosis, or severe electrolyte imbalances in critically ill patients.

A computerized cycler performs four or more exchanges nightly, each lasting 1-2 hours with 2-3 liters of dialysate. After each dwell period, waste-filled dialysate drains and fresh solution replaces it, enabling ongoing removal throughout the night. Some patients need 1-2 additional manual daytime exchanges to achieve adequate solute and fluid clearance.

Peritonitis results from contamination during catheter handling or exchanges. Common pathogens include Staphylococcus epidermidis and aureus, with gram-negative bacteria like Escherichia coli and Pseudomonas aeruginosa also responsible. Prompt antibiotic treatment is critical to prevent serious complications and infection progression in affected patients.

Increased intra-abdominal pressure from dialysate can cause hernias, particularly in older men and women with multiple pregnancies. Pressure also contributes to lower back pain and pulmonary issues including atelectasis and pneumonia. Pleuroperitoneal communication may cause pleural effusions, requiring regular exercise, orthopedic support, and proper positioning for management.

Protein loss occurs due to peritoneal membrane permeability and increases significantly during peritonitis episodes. Gradual protein loss over time can lead to malnutrition. Dietary adjustments with increased protein intake typically manage mild cases, though severe protein loss may require alternative dialysis methods or additional nutritional interventions.

Bleeding in effluent commonly occurs after catheter insertion and usually resolves independently without intervention. However, persistent or new bleeding may indicate intraperitoneal hemorrhage requiring immediate medical evaluation and assessment. Prompt clinical distinction between normal post-insertion bleeding and serious internal bleeding complications is essential for patient safety.