How to initiate peritoneal dialysis (PD) in a post-coronary artery bypass grafting (CABG) patient with low cardiac output syndrome (LCOS) and anuria, without access to continuous renal replacement therapy (CRRT)?

Initiating Peritoneal Dialysis in Post-CABG Patient with LCOS and Anuria

In your post-CABG patient with low cardiac output syndrome and anuria, initiate PD immediately with low-volume supine dialysis using 500-1000 mL exchanges (approximately 10-15 mL/kg) performed hourly or every 2 hours in the supine position, then gradually increase to full-volume exchanges (2.0-3.0 L based on BSA) over 7-10 days as tolerated. 1

Immediate Initiation Protocol

Starting Parameters (First 48-72 Hours)

• Begin with reduced fill volumes of 500-1000 mL to minimize risk of dialysate leak, catheter dysfunction, and hemodynamic compromise in this critically ill cardiac patient 1
• Keep patient strictly supine during exchanges to reduce intra-abdominal pressure and leak risk 1
• Use short dwell times (1-2 hours initially) with frequent exchanges to maximize solute clearance in this anuric patient 1
• Monitor hemodynamics closely during each exchange, as fluid shifts may worsen LCOS 2

Volume Escalation Strategy (Days 3-10)

• Increase fill volume by 200-500 mL every 1-2 days as tolerated, targeting final volumes based on BSA 1, 3:
  • BSA <1.7 m²: target 2.0 L per exchange
  • BSA 1.7-2.0 m²: target 2.5 L per exchange
  • BSA >2.0 m²: target 3.0 L per exchange 1, 3
• Maintain supine position until reaching at least 1.5 L fill volumes without complications 1
• Watch for catheter dysfunction, leaks, or hernias during escalation—these occur in 13-27% of urgent-start cases 4

Target Prescription for Anuric Patient

Full-Dose Requirements

Since your patient is anuric (no residual kidney function), you must achieve the entire weekly Kt/V of 2.0 from peritoneal clearance alone 1, 3. This requires:

• Four 2.0-3.0 L exchanges daily for CAPD, or 1, 3
• Automated PD with 9-10 hours nightly PLUS mandatory daytime dwells (approximately 85% of anuric patients require daytime exchanges to reach targets) 1, 3

Critical Monitoring in First Month

• Measure delivered Kt/V and creatinine clearance at 2-4 weeks using 24-hour dialysate collections 1, 5, 3
• Assess volume status and ultrafiltration adequacy daily initially, then weekly 1, 3
• Perform peritoneal equilibration test (PET) at 4 weeks to characterize transport status and optimize prescription 5, 6

Special Considerations for Post-CABG/LCOS Context

Hemodynamic Management

• Avoid rapid ultrafiltration that could worsen cardiac output—use isosmolar or 1.5% dextrose initially if volume removal not urgent 7, 2
• Consider higher dialysate sodium (132-140 mEq/L) to reduce intradialytic hypotension risk 2
• Coordinate with cardiology regarding inotrope/vasopressor adjustments as uremia improves 2

Metabolic Correction Timeline

• Expect >50% reduction in urea within first 7 days even with urgent-start low-volume PD 4
• Potassium and bicarbonate normalize similarly to hemodialysis by day 7 4
• Total fluid removal averages 1.2 L less than hemodialysis in first week, but this difference is clinically manageable in most cases 4

Common Pitfalls to Avoid

Technical Errors

• Do not use full 2-3 L volumes immediately—this dramatically increases leak and dysfunction risk when starting <10 days post-catheter placement 1
• Do not allow patient upright positioning until tolerating at least 1.5 L volumes for 48 hours 1
• Do not assume nighttime-only automated PD will suffice—anuric patients almost always need daytime dwells to reach Kt/V targets 1, 3

Clinical Misjudgments

• Do not delay increasing prescription if Kt/V <2.0—mortality and malnutrition risk increase substantially below this threshold 1, 3
• Do not confuse poor drainage from catheter malposition with low transporter status—verify catheter function before adjusting prescription 5
• Do not overlook residual kidney function assessment—though your patient is currently anuric, even minimal recovery (>100 mL/day urine) significantly impacts prescription needs 1, 3

Outcome Expectations

Recent data show 90-day mortality is similar (20.8% PD vs 29.1% HD) in severe symptomatic uremia, with comparable uremia correction and technique survival 4. Your patient's LCOS and post-surgical status increase baseline risk, but PD remains a viable option when CRRT unavailable 8, 4.