From the Guidelines
For a patient on triple inotropic support, the recommended CRRT prescription typically includes a dose of 20-25 mL/kg/hour of effluent flow rate, as suggested by the most recent and highest quality study 1. The modality of choice is often continuous venovenous hemodiafiltration (CVVHDF) as it provides both diffusive and convective clearance, optimizing solute removal while maintaining hemodynamic stability. Some key points to consider when prescribing CRRT for these patients include:
- Anticoagulation should be approached cautiously, with regional citrate anticoagulation often preferred over systemic heparin to reduce bleeding risk in these critically ill patients, as recommended by 1.
- The ultrafiltration rate should be modest, typically starting at 50-100 mL/hour and titrating based on hemodynamic tolerance, as these patients are particularly sensitive to volume shifts.
- Blood flow rates should be maintained between 150-200 mL/minute to balance clearance needs with hemodynamic stability.
- Frequent reassessment of the patient's fluid status, electrolytes (particularly potassium, calcium, and phosphate), and acid-base balance is essential, with adjustments to the prescription made accordingly. This intensive approach is necessary because patients requiring triple inotropic support have severe cardiovascular compromise and are at high risk for hemodynamic collapse with conventional CRRT settings. It's also important to note that individualization of the intensity of CRRT may be required to meet a patient’s requirements for maintenance of electrolyte and fluid balance, as suggested by 1. In terms of specific CRRT prescription, the following parameters can be considered:
- Effluent flow rate: 20-25 mL/kg/hour
- Modality: CVVHDF
- Anticoagulation: regional citrate anticoagulation
- Ultrafiltration rate: 50-100 mL/hour
- Blood flow rate: 150-200 mL/minute
- Buffer: bicarbonate, as recommended by 1
- Replacement fluid: should comply with American Association of Medical Instrumentation (AAMI) standards regarding contamination with bacteria and endotoxins, as recommended by 1.
From the Research
CRRT Prescription for a Patient on Triple Inotropic Support
The following is a recommended CRRT prescription based on the available evidence:
- Modality: Continuous Venovenous Hemofiltration with Dialysis (CVVHD) 2
- Blood Flow Rate: 150-200 ml/min 2
- Dialysate Composition: Calcium-free dialysate with moderate sodium (135 mEq/l) and bicarbonate (28 mEq/l) concentrations 2
- Ultrafiltration Rate: Limited to that needed for overall fluid balance in the intensive care unit 2
- Anticoagulation: Regional citrate anticoagulation (RCA) with citrate infusion into the extracorporeal blood and calcium repletion in blood returned to the patient, proportional to blood flow 2, 3, 4
- Citrate Infusion Rate: Adjusted to maintain extracorporeal ionized calcium below 0.4 mM/l 2
- Calcium Repletion Rate: Adjusted to maintain systemic calcium levels within normal range 2, 5
Considerations for Patients with Liver Disease or Sepsis
- Liver Disease: Median filter life may be significantly lower (33.5 hours) compared to patients without liver disease 5
- Sepsis: No significant differences in renal recovery or hospital mortality were observed between patients with sepsis and those without 3