What is the recommended night dwell duration for patients initiating peritoneal dialysis (PD)?

Recommended Night Dwell Duration for Patients Initiating Peritoneal Dialysis

For patients initiating peritoneal dialysis, a night dwell of 9 hours is recommended for optimal middle-molecule clearance and solute removal. 1

Rationale for Night Dwell Duration

The night dwell is a critical component of the peritoneal dialysis (PD) prescription that serves multiple important purposes:

• Maximizes middle-molecule clearance, which is time-dependent
• Optimizes solute removal during the longest uninterrupted period
• Improves volume control, directly impacting mortality and morbidity outcomes

Initial Prescription Considerations

When initiating PD, the following factors should guide the night dwell prescription:

1. Body Surface Area (BSA):

   • BSA < 1.7 m²: 2.0 L exchanges with 9-hour night dwell for CCPD
   • BSA 1.7-2.0 m²: 2.5 L exchanges with 9-hour night dwell for CCPD
   • BSA > 2.0 m²: 3.0 L exchanges with 9-hour night dwell for CCPD 1

2. Residual Kidney Function (RKF):

   • For eGFR < 2 mL/min: 9-hour night dwell with 2.0-3.0 L volume
   • For eGFR ≥ 2 mL/min: 9-10 hour night dwell with 2.5-3.0 L volume 1

Modality-Specific Considerations

For CAPD (Continuous Ambulatory Peritoneal Dialysis):

• The night dwell represents one of the four standard exchanges
• Should be optimized with appropriate volume based on BSA
• Typically the longest uninterrupted dwell period

For APD (Automated Peritoneal Dialysis):

• The cycler typically runs for approximately 9 hours overnight 1
• Multiple shorter cycles occur during this period
• A daytime dwell should be included to ensure 24-hour coverage

Transport Characteristics and Night Dwell

Peritoneal Equilibration Testing (PET) should be performed approximately 1 month after PD initiation to determine membrane transport characteristics 2. This will help optimize the night dwell:

• Low transporters: Require longer dwell times to achieve adequate solute clearance
• High transporters: May experience ultrafiltration problems with long dwells and might benefit from shorter dwell times or use of icodextrin for the night dwell

Optimizing Ultrafiltration During Night Dwell

For patients with hypertension or volume overload, ultrafiltration should be positive for all exchanges, including the night dwell 1. Strategies include:

• Using appropriate dextrose concentration
• Considering icodextrin for the long night dwell if ultrafiltration is inadequate
• Monitoring drain volumes monthly to ensure adequate ultrafiltration

Research shows that with icodextrin, ultrafiltration does not increase significantly beyond 10 hours of dwell time 3, suggesting that night dwells of 9-10 hours are appropriate when using this solution.

Practical Approach to Night Dwell Duration

1. Start with a standard 9-hour night dwell
2. Adjust based on:
   • Ultrafiltration results
   • Transport characteristics from PET
   • Patient's volume status
   • Residual kidney function

Common Pitfalls to Avoid

• Ignoring transport characteristics: Can lead to suboptimal clearance and ultrafiltration 1
• Neglecting volume status: May result in undetected volume overload 1
• Starting with full-volume exchanges immediately after catheter placement: Increases risk of leakage; begin with low-volume, supine dialysis 1
• Focusing solely on small-molecule clearance: Middle-molecule clearance requires adequate dwell time, making the night dwell essential

By following these guidelines and adjusting based on individual patient characteristics, the night dwell can be optimized to improve clinical outcomes in patients initiating peritoneal dialysis.