When is Continuous Renal Replacement Therapy (CRRT) preferred over Hemodialysis (HD)?

From the Guidelines

Continuous Renal Replacement Therapy (CRRT) is preferred over Hemodialysis (HD) in hemodynamically unstable patients who cannot tolerate the rapid fluid and electrolyte shifts of conventional hemodialysis, as suggested by the most recent and highest quality study 1.

Indications for CRRT

The following conditions are indications for CRRT over HD:

• Hemodynamic instability, such as hypotension (systolic blood pressure <90 mmHg or requiring vasopressor support)
• Severe heart failure
• Cerebral edema
• Increased intracranial pressure
• Severe metabolic acidosis
• Hyperkalemia with hemodynamic compromise
• Multiple organ failure requiring precise volume management

CRRT Modalities

The main CRRT modalities include:

• Continuous venovenous hemofiltration (CVVH)
• Continuous venovenous hemodialysis (CVVHD)
• Continuous venovenous hemodiafiltration (CVVHDF) The choice of modality depends on the specific clinical situation and institutional practices.

Advantages of CRRT

CRRT allows for gentler fluid removal (typically 25-35 mL/kg/hour) and solute clearance over 24 hours, rather than the rapid changes that occur during a 3-4 hour hemodialysis session. However, CRRT requires continuous anticoagulation (typically with citrate or heparin), specialized ICU nursing care, and is generally more expensive than intermittent hemodialysis, as noted in 1 and 1.

Key Considerations

When choosing between CRRT and HD, it is essential to consider the patient's clinical status, available resources, and expertise of personnel, as emphasized in 1. The decision to use CRRT or HD should be based on the individual patient's needs and the specific clinical circumstances.

From the Research

Overview of Continuous Renal Replacement Therapy (CRRT) and Hemodialysis (HD)

• CRRT is preferred over HD in certain situations, including:
  • Patients with severe hyperphosphatemia 2
  • Patients with elevated intracranial pressure, cerebral edema complicating acute liver failure, sepsis or septic shock 2
  • Patients with lithium intoxication 2
  • Hemodynamically unstable patients 3, 4
• CRRT offers advantages over HD, including:
  • Greater hemodynamic stability 2, 3
  • Better fluid management 3
  • Greater solute control 3
  • Lower bleeding risk 3

Clinical Scenarios where CRRT is Preferred

• CRRT is the preferred dialysis modality for solute management, acid-base stability, and volume control in patients who are critically ill with AKI in the intensive care unit (ICU) 3
• Patients with multiorgan dysfunction syndrome, including AKI, may benefit from CRRT 5
• CRRT is indicated for patients with oligoanuric patients with diuretic resistant volume overload and hemodynamically unstable patients with acute renal failure and concomitant sepsis or multiorgan failure 6

Comparison of CRRT and HD

• There is no significant difference in mortality or renal recovery between CRRT and HD for critically ill patients with AKI 2, 4
• HD is more practical, cost-effective, and does not require anticoagulation, but may not provide the same level of hemodynamic stability as CRRT 5
• The choice of RRT modality should be based on the individual patient's needs, including hemodynamic status, coexisting medical conditions, and local expertise and resources 4