What should my Continuous Renal Replacement Therapy (CRRT) removal goal be with a Central Venous Pressure (CVP) of 12 and Pulmonary Capillary Wedge Pressure (PCWP) of 18?

CRRT Fluid Removal Goals with CVP 12 and PCWP 18

For a patient with CVP of 12 mmHg and PCWP of 18 mmHg, the CRRT fluid removal goal should be to achieve a negative fluid balance while maintaining hemodynamic stability, with careful monitoring of perfusion parameters to guide the rate of removal.

Hemodynamic Assessment and Interpretation

Your patient's hemodynamic parameters indicate:

• CVP of 12 mmHg: At the upper limit of normal (8-12 mmHg)
• PCWP of 18 mmHg: Elevated above normal (6-12 mmHg)

These values suggest:

• Mild volume overload
• Potential cardiac dysfunction (elevated filling pressures)
• Need for careful fluid removal to optimize preload without compromising cardiac output

CRRT Fluid Removal Strategy

Initial Approach

• Start with a moderate fluid removal rate of 50-100 mL/hour
• Target a negative fluid balance of approximately 1-2 mL/kg/hour 1
• Adjust based on hemodynamic response and perfusion parameters

Monitoring Parameters During Fluid Removal

Monitor the following parameters hourly to guide adjustments:

• Mean arterial pressure (MAP): Maintain ≥65 mmHg 2
• Cardiac index (CI): Maintain >3.3 L/min/m² 1
• Central venous oxygen saturation (ScvO₂): Keep >70% 1
• Perfusion pressure (MAP-CVP): Maintain appropriate for age 1
• Capillary refill: Keep ≤2 seconds 1
• Urine output: Maintain >0.5 mL/kg/hour (if present) 2
• Peripheral temperature: Watch for cooling extremities 3
• Lactate/base excess: Monitor for worsening 3

Adjustment Algorithm

1. If hemodynamically stable with all parameters maintained:

   • Continue or gradually increase fluid removal rate

2. If showing signs of hemodynamic compromise:

   • Decrease or temporarily stop fluid removal if:
     • ScvO₂ drops below 70%
     • MAP falls below 65 mmHg
     • CI decreases below 3.3 L/min/m²
     • Peripheral extremities become cold
     • Lactate increases or base deficit worsens

3. Reassess every hour and adjust fluid removal rate accordingly 3

Special Considerations

Volume Status Assessment

• The elevated PCWP (18 mmHg) suggests left ventricular filling pressure is high
• CVP of 12 mmHg is at the upper limit of normal range
• These values together suggest the patient can likely tolerate careful fluid removal

Avoiding Common Pitfalls

1. Avoid excessive fluid removal rates:

   • Rapid fluid removal can precipitate hemodynamic instability
   • Protocol-driven approaches have shown that careful monitoring allows for significant fluid removal (up to 59 mL/kg/day) in selected patients 3

2. Don't rely solely on static pressure measurements:

   • CVP and PCWP are poor predictors of fluid responsiveness 1
   • Dynamic parameters provide better guidance for fluid management

3. Beware of fluid overload consequences:

   • Volume overload is associated with adverse outcomes, especially in acute lung injury 1
   • Maintaining negative fluid balance decreases ICU length of stay 1

4. Continuous monitoring is essential:

   • In one study, 12% of fluid removal rate evaluations required decreasing or stopping fluid removal 3
   • Most common reasons were: low ScvO₂ (28%), low MAP (23%), low CI (17%), and cold extremities (14%) 3

Conclusion

With a CVP of 12 mmHg and PCWP of 18 mmHg, your patient likely has some degree of volume overload and would benefit from careful fluid removal via CRRT. Start with a moderate removal rate (50-100 mL/hour), monitor hemodynamic parameters closely, and adjust hourly based on the patient's response to achieve optimal fluid balance while maintaining adequate tissue perfusion.