What are the guidelines for initiating and managing peritoneal (PD) dialysis in patients with impaired renal function?

Peritoneal Dialysis: Initiation and Management Guidelines

Patient Selection and Pre-Dialysis Preparation

All treatment options (transplant, hemodialysis, and peritoneal dialysis) should be explained to patients in an unbiased manner, with modality selection based on medical suitability, patient preference, and absence of contraindications. 1

Initial Patient Evaluation

• Review the patient's medical condition and comorbidities to identify absolute or relative contraindications to PD (e.g., severe abdominal adhesions, active abdominal wall infection, inability to perform exchanges) 1
• If no medical contraindications exist and the patient is capable of self-therapy, allow the patient to choose their preferred modality 1
• Education should begin when patients reach CKD stage 4 (GFR <30 mL/min/1.73 m²) to allow adequate time for decision-making and access placement 1

Catheter Placement and Dialysis Initiation

Catheter Insertion Timing and Technique

• Wait 10 days to 2 weeks after catheter placement before starting PD to allow proper healing and reduce complications 1
• If dialysis must be started in less than 10 days following catheter placement, perform low-volume (typically 1-1.5 L), supine dialysis to minimize leak risk 1
• Flexible peritoneal catheters should be used where resources and expertise exist, with tunneling recommended to reduce peritonitis and peri-catheter leak 2
• Prophylactic antibiotics should be administered prior to catheter implantation 2

Baseline Assessment at Initiation

• Obtain baseline 24-hour urine collection for urea and creatinine clearance to calculate solute clearance, assess creatinine generation, and determine protein nitrogen appearance (PNA) 1
• Document the patient's weight and presence or absence of edema 1
• Explain that the prescription will be individualized and that instilled volumes will almost certainly need to increase over time 1

Initial Dialysis Prescription

Prescription Based on Residual Kidney Function (RKF)

PD may be initiated incrementally or as full therapy, depending on residual kidney function at the time of initiation. 1

For Patients with Estimated GFR ≥2 mL/min:

• Start with lower dialysis doses and supplement with residual kidney function to achieve target weekly Kt/Vurea of at least 2.0 1
• For CAPD: 2.5 L/day for BSA <1.7 m² 1
• Incremental approach example: If residual Kt/Vurea is 1.8 per week, only 0.2 peritoneal Kt/Vurea is needed; a single 2-L overnight exchange would contribute approximately 0.35 Kt/Vurea per week, achieving the target of 2.0-2.15 1

For Patients with Estimated GFR <2 mL/min:

CAPD Prescription (4 exchanges daily):

• BSA <1.7 m²: 2.0 L exchanges, 4 times daily 1
• BSA 1.7-2.0 m²: 2.5 L exchanges, 4 times daily 1
• BSA >2.0 m²: 3.0 L exchanges, 4 times daily 1

CCPD/APD Prescription (cycler-based):

• BSA <1.7 m²: 2.0 L cycles (9 hours/night) + 2.0 L daytime dwell 1
• BSA 1.7-2.0 m²: 2.5 L cycles (9 hours/night) + 2.0 L daytime dwell 1
• BSA >2.0 m²: 3.0 L cycles (9 hours/night) + 3.0 L daytime dwell 1

Critical Patient Education at Initiation

• Inform patients choosing APD that approximately 85% will need one or more daytime dwells in addition to nighttime cycling 1
• Explain that prescriptions will change over time as residual kidney function declines or peritoneal transport characteristics change 1

Adequacy Targets and Monitoring

Minimum Dialysis Dose Requirements

The minimum weekly Kt/Vurea target is 2.0 for patients with minimal residual function, combining both peritoneal and residual kidney clearance. 1

• For patients with peritoneal Kt/Vurea ≥1.7 or 24-hour urine output <100 mL, routine monitoring of residual kidney function is not required for adequacy assessment 1
• 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

Timing of Adequacy Assessment

• Perform peritoneal equilibration testing (PET) approximately 1 month after dialysis initiation to characterize peritoneal transport characteristics 3
• Obtain 24-hour dialysate and urine collections 2-4 weeks after initiation to measure Kt/Vurea and creatinine clearance 3
• Measure creatinine, urea, potassium, and bicarbonate levels regularly; daily monitoring is optimal in unstable patients 4

Indications for Increasing Dialysis Dose

• If a patient is not thriving without other identifiable cause, increase the dialysis dose regardless of measured adequacy 1
• Specific indications include uremic pericarditis, uncontrolled uremic symptoms, or persistent metabolic derangements 1

Prescription Adjustments Based on Transport Status

Low Transporters

• Generally require high-dose prescriptions (CAPD or CCPD) with larger volumes to achieve adequate creatinine clearance 3
• May need volumes increased to 2.5-3.0 L depending on body surface area 3
• Consider switching to hemodialysis if adequate clearance cannot be achieved despite maximal PD prescription 3

High/Rapid Transporters

• Benefit from continuous 24-hour dwells (rather than intermittent) to maximize middle-molecule clearance 1
• May require shorter dwell times to optimize ultrafiltration 3

Dialysate Solutions and Electrolyte Management

Solution Selection

• Commercially prepared solutions should be used when available 2
• In critically ill patients with significant liver dysfunction and elevated lactate, bicarbonate-containing solutions should be used 2
• A closed delivery system with Y-connection should be used to minimize infection risk 2

Potassium Management

• Once serum potassium falls below 4 mmol/L, add potassium to dialysate (using strict sterile technique) or provide oral/IV supplementation to maintain levels ≥4 mmol/L 2
• After 24 hours of successful dialysis, consider adding potassium chloride to achieve 4 mmol/L concentration in dialysate 2

Nutritional Monitoring

• Monitor serum albumin levels during monthly evaluations 1
• When obtaining 24-hour total solute clearances, measure dietary protein intake estimates (such as normalized protein nitrogen appearance) 1
• Nutritional status should be assessed at each monthly evaluation 1

Common Pitfalls and Critical Considerations

Compliance and Education

• Noncompliance is a major cause of delivered dose being less than prescribed dose 1
• Patient education should be continuous throughout PD, with teaching repeated at 6-month intervals or less 1
• Patients should understand target Kt/V and creatinine clearance values and their clinical significance 1
• Emphasize positive outcomes of adherence (improved survival, well-being) rather than negative consequences to prevent excessive anxiety 1

Technique Failure Prevention

• Infectious complications, particularly peritonitis, remain the main cause of PD failure and are associated with the highest morbidity and mortality 5
• Surgical observation is mandatory for any peritonitis case; absence of response to medical treatment within 48-72 hours indicates need for peritoneal cavity exploration 5
• Encapsulating peritoneal sclerosis is rare but serious, with 20% mortality; risk increases with duration of PD treatment 5

Indications for Transfer to Hemodialysis

• Consistent failure to achieve target Kt/Vurea and creatinine clearance despite maximal PD prescription 4
• Inadequate solute transport or fluid removal 4
• Recurrent peritonitis or catheter-related infections leading to membrane failure 5