What is the procedure for performing peritoneal dialysis in a patient with impaired renal function?

How to Perform Peritoneal Dialysis

Pre-Dialysis Patient Evaluation and Access Placement

Before initiating peritoneal dialysis, place a chronic peritoneal dialysis catheter (typically a double-cuffed Tenckhoff catheter) and ideally wait 10-14 days before starting full-volume dialysis to allow proper healing and reduce leak risk. 1

• Explain all renal replacement options (transplant, hemodialysis, and peritoneal dialysis) to patients in a non-biased manner 1
• Review medical comorbidities to identify absolute or relative contraindications to peritoneal dialysis 1
• Absolute contraindications include documented loss of peritoneal function or extensive abdominal adhesions limiting dialysate flow 2
• Relative contraindications include recent intra-abdominal foreign bodies, morbid obesity, severe malnutrition, and frequent diverticulitis 2
• The catheter can be placed surgically or percutaneously with equivalent 1-year catheter survival rates, though percutaneous placement shows lower infectious and mechanical complication rates in randomized trials 3

Immediate Post-Catheter Initiation Protocol (If Dialysis Needed Urgently)

If dialysis must be started within 10 days of catheter placement, begin with low-volume supine dialysis using 500-1000 mL exchanges performed hourly or every 2 hours with the patient strictly supine. 1, 4

• Use reduced fill volumes of 500-1000 mL (approximately 10-15 mL/kg) to minimize risk of dialysate leak, catheter dysfunction, and hemodynamic compromise 4
• Keep patient strictly supine during exchanges to reduce intra-abdominal pressure and leak risk 4
• Use short dwell times (1-2 hours initially) with frequent exchanges to maximize solute clearance 4
• Gradually increase to full-volume exchanges (2.0-3.0 L based on body surface area) over 7-10 days as tolerated 4
• Increase fill volume by 200-500 mL every 1-2 days as tolerated 4

Standard Initiation Protocol (After 10-14 Day Healing Period)

After the recommended 10-14 day healing period, initiate peritoneal dialysis with full-volume exchanges based on the patient's body surface area, residual kidney function, and lifestyle constraints. 1

Target Fill Volumes by Body Surface Area:

• BSA <1.7 m²: 2.0 L per exchange 4
• BSA 1.7-2.0 m²: 2.5 L per exchange 4
• BSA >2.0 m²: 3.0 L per exchange 4

Initial Prescription Strategy:

• Peritoneal dialysis may be initiated incrementally or as full therapy depending on residual kidney function at initiation 1
• For patients with significant residual kidney function (Kt/V urea ≥1.8 per week), only minimal peritoneal clearance (Kpt/V urea 0.2) is initially needed 1
• For anuric patients, the entire weekly Kt/V of 2.0 must come from peritoneal clearance alone 4

Dialysis Modality Selection

Peritoneal dialysis can be performed manually (continuous ambulatory peritoneal dialysis) with 4 solution changes throughout the day, or machine-assisted (automated peritoneal dialysis) with overnight cycling while the patient sleeps. 5

Continuous Ambulatory Peritoneal Dialysis (CAPD):

• Four 2.0-3.0 L exchanges daily performed manually by the patient 4
• Each exchange involves infusing dialysate, allowing a dwell period (typically 4-6 hours), then draining 5

Automated Peritoneal Dialysis (APD):

• Machine performs 9-10 hours of nightly exchanges while patient sleeps 4
• Approximately 85% of anuric patients require mandatory daytime dwells in addition to nighttime automated peritoneal dialysis to reach adequacy targets 1, 4
• For patients with minimal residual kidney function, use continuous 24-hour peritoneal dialysis (rather than intermittent) to maximize middle-molecule clearance 1

Baseline Assessment and Monitoring

Obtain baseline 24-hour urine collection for urea and creatinine clearance at initiation, then measure delivered Kt/V and creatinine clearance at 2-4 weeks using 24-hour dialysate collections. 1, 4

Initial Assessment:

• Collect 24-hour urine for urea and creatinine clearance calculations, assessment of creatinine generation, and protein nitrogen appearance (PNA) determinations 1
• Note patient's weight and presence or absence of edema 1
• Perform peritoneal equilibration test (PET) at 4 weeks to characterize transport status and optimize prescription 4

Ongoing Monitoring:

• All measurements of peritoneal solute clearance should be obtained when the patient is clinically stable and at least 1 month after resolution of peritonitis 1
• If peritoneal Kt/V urea is at least 1.7 or 24-hour urine output is less than 100 mL, monitoring of residual kidney function is not required for dose monitoring (though periodic measurement may still be valuable) 1
• More frequent measurements of peritoneal urea clearance or residual kidney function should be obtained when clinically indicated 1

Adequacy Targets and Prescription Adjustment

Target a minimum weekly Kt/V urea of 2.0 (combined peritoneal and residual kidney function) for all peritoneal dialysis patients. 4

• When calculating Kt/V urea, estimate V from either the Watson or Hume equation in adults 1
• Consider using the patient's ideal or standard weight (rather than actual weight) in the calculation of V 1
• Peritoneal creatinine clearance determination is of little added value for predicting mortality risk; adequacy targets are based on urea kinetics only 1
• Regardless of delivered dose, if a patient is not thriving and has no other identifiable cause, increase the dialysis dose 1

Fluid and Volume Management

Optimize extracellular water and blood volume through dietary sodium and water restriction, diuretics in patients with residual kidney function, and optimization of peritoneal ultrafiltration. 1

Ultrafiltration Strategies:

• Avoid long-duration dwells that frequently result in net peritoneal fluid absorption 1
• For automated peritoneal dialysis patients, shorten the day dwell and leave patient "dry" for part of the day, or drain and replace the day dwell partway through 1
• For continuous ambulatory peritoneal dialysis patients, switch to automated peritoneal dialysis without a long day dwell or use a night-exchange device to divide the nocturnal dwell 1
• Use icodextrin solution for long dwells (nocturnal in continuous ambulatory peritoneal dialysis, day in automated peritoneal dialysis) to increase peritoneal ultrafiltration and decrease extracellular fluid volume 1

Pharmacologic Support:

• High-dose loop diuretics can enhance urinary sodium and water removal in patients with residual kidney function 1
• ACE inhibitors and ARBs help maintain urinary volume and clearance better in peritoneal dialysis patients 1

Nutritional Monitoring

During monthly evaluation, estimate nutritional status by monitoring serum albumin levels and calculating dietary protein intake (such as normalized protein nitrogen appearance) when obtaining 24-hour total solute clearances. 1

• Continuous protein loss through the peritoneum can contribute to malnutrition 6, 2
• Low molecular weight macronutrients and micronutrients are lost during treatment 6

Critical Pitfalls to Avoid

• Do not use full 2-3 L volumes immediately when starting less than 10 days post-catheter placement—this dramatically increases leak and dysfunction risk 4
• Do not allow patient upright positioning until tolerating at least 1.5 L volumes for 48 hours 4
• Do not assume nighttime-only automated peritoneal dialysis will suffice in anuric patients—they almost always need daytime dwells to reach Kt/V targets 1, 4
• Do not delay increasing prescription if Kt/V is less than 2.0—mortality and malnutrition risk increase substantially below this threshold 4
• Do not confuse poor drainage from catheter malposition with low transporter status—verify catheter function before adjusting prescription 4
• Do not overlook residual kidney function assessment—even minimal recovery (greater than 100 mL/day urine) significantly impacts prescription needs 4

Patient Education at Initiation

Explain to patients at the start that their prescription will be individualized and that instilled volume will almost certainly need to increase over time. 1

• Inform patients choosing automated peritoneal dialysis that one or more daytime dwells will be needed in approximately 85% of cases 1
• Advise that total solute clearance will be monitored and that prescription may need to change if residual kidney function or peritoneal transport changes over time 1