Duration of Peritoneal Dialysis Treatment
Peritoneal dialysis (PD) runs continuously 24 hours per day, 7 days per week, with different modalities varying in how exchanges are performed rather than total treatment time.
Treatment Modalities and Their Duration
Continuous Ambulatory Peritoneal Dialysis (CAPD)
- Operates 24/7 with fluid continuously dwelling in the peritoneal cavity 1
- Requires 4 manual exchanges throughout the day, with each exchange remaining in the abdomen for several hours 2
- Each dwell period allows continuous solute and fluid removal 3
Automated Peritoneal Dialysis (APD)
- Also runs 24 hours daily but concentrates exchanges during nighttime hours 1
- Cycling machine performs exchanges overnight, typically 9-10 hours per night 1
- Approximately 85% of APD patients require one or more daytime dwells in addition to nighttime cycling to achieve adequate clearance 1
- The daytime dwell remains in place throughout waking hours, maintaining continuous dialysis 1
Nightly Intermittent Peritoneal Dialysis (NIPD)
- Reserved for specific patient populations (high/rapid transporters with significant residual kidney function) 1
- Performs exchanges only during nighttime hours without daytime dwells 1
- Less commonly used as initial therapy due to inadequate clearance in most patients 1
Key Distinction from Hemodialysis
Unlike hemodialysis which runs intermittently (typically 3-4 hours, three times weekly), PD provides continuous renal replacement therapy throughout the entire week 1. This fundamental difference means:
- PD delivers dialysis 168 hours per week versus hemodialysis's 9-12 hours per week 1
- The continuous nature allows for gentler, more physiologic solute and fluid removal 2
- Weekly clearance targets (Kt/V ≥2.0) account for this continuous treatment schedule 1
Clinical Implications
The continuous nature of PD means patients are "on dialysis" at all times, whether actively exchanging fluid (CAPD manual exchanges or APD nighttime cycling) or during dwell periods when dialysate remains in the peritoneal cavity performing clearance 2, 3. This differs fundamentally from asking "how many hours" hemodialysis runs, as PD is an ongoing process rather than intermittent sessions.