What is the treatment for acute kidney injury after cardiac arrest?

Treatment of Acute Kidney Injury After Cardiac Arrest

The treatment of acute kidney injury (AKI) after cardiac arrest centers on close monitoring of kidney function, optimizing hemodynamics through goal-directed fluid therapy and vasopressor support, avoiding nephrotoxic medications, and initiating renal replacement therapy when indicated, particularly in cases with fluid overload. 1, 2

Monitoring and Early Detection

• Monitor kidney function closely including urine output and serum creatinine throughout post-cardiac arrest care, as patients are at high risk for developing AKI. 1
• AKI occurs in approximately 37-52% of cardiac arrest survivors, with onset typically within 1-2 days after return of spontaneous circulation (ROSC). 3
• In pediatric patients, 37% develop AKI after cardiac arrest, with 11.5% developing severe AKI and 6.4% requiring renal replacement therapy within 48 hours of ROSC. 1, 2
• Urinary biomarkers (tissue inhibitor of metalloproteinases-2 and insulin-like growth factor-binding protein 7) can identify at-risk patients as early as 1 hour after cardiopulmonary bypass in cardiac surgery patients. 2

Hemodynamic Optimization

Goal-directed fluid therapy is critical and should use standardized algorithms targeting specific hemodynamic parameters. 2, 4

Fluid Management

• Use isotonic crystalloids rather than colloids for volume expansion in patients at risk of AKI. 2
• Avoid starch-containing fluids in at-risk patients. 2
• Implement goal-directed fluid therapy with quantified targets for blood pressure, cardiac index, systemic venous oxygen saturation, and urine output. 2
• Volumetric (extravascular lung water index, global end-diastolic volume index) and arterial waveform-derived variables (pulse pressure variation, stroke volume variation) can guide fluid therapy and reduce AKI incidence. 4
• In one study, hemodynamic-guided fluid therapy (averaging 5449±1438 mL in first 24 hours) significantly reduced severe AKI compared to conventional monitoring (4375±1285 mL), with RIFLE 'I'/'F' occurring in only 4.3% versus 28.6%. 4

Blood Pressure Goals

• Target a mean arterial pressure of at least 65 mm Hg, though optimal blood pressure goals remain uncertain. 1
• Use vasopressors (such as norepinephrine) in conjunction with fluids in patients with vasomotor shock to maintain adequate perfusion pressure. 1, 2
• Titrate inotropic agents (such as dobutamine) and inodilators (such as milrinone) as needed to optimize cardiac output and systemic perfusion. 1
• Monitor central venous oxygen saturation with a target of 70% as a reasonable goal. 1

Medication Management

Nephrotoxic medications must be avoided or used with extreme caution. 1, 2

• Discontinue ACE inhibitors and angiotensin II receptor blockers for 48 hours post-cardiac arrest. 2
• Use aminoglycosides only when no suitable, less nephrotoxic alternatives are available, and when necessary, administer as a single daily dose with close monitoring of drug levels. 2
• Adjust medication dosages for patients with impaired kidney function. 1
• Closely monitor serum concentrations of nephrotoxic medications. 1
• Avoid radiocontrast agents when possible in at-risk patients. 2

Medications NOT Recommended

• Do not use low-dose dopamine to prevent or treat AKI. 2
• Do not use fenoldopam to prevent or treat AKI. 2
• Do not use atrial natriuretic peptide to prevent or treat AKI. 2
• Do not use recombinant human IGF-1 for AKI prevention or treatment. 2
• Diuretics should not be used to prevent AKI but may be used to manage volume overload once AKI is established. 2

Metabolic Management

• Target moderate glycemic control (144-180 mg/dL or 8-10 mmol/L) in adult patients with ROSC after cardiac arrest. 1
• Do not attempt tight glucose control (80-110 mg/dL) due to increased risk of hypoglycemia and potential for worse outcomes. 1
• Maintain plasma glucose between 110-149 mg/dL (6.1-8.3 mmol/L) in pediatric patients to avoid hyperglycemia. 2

Renal Replacement Therapy

Consider early initiation of RRT, particularly in cases with fluid overload. 2, 5

• Approximately 33% of AKI patients after cardiac arrest require RRT, with only 2% remaining dialysis-dependent at 30 days. 3
• The decision to initiate RRT should be based on clinical status including degree of fluid overload, electrolyte abnormalities, and acid-base status. 5
• Use of vasopressors is strongly associated with both development of AKI and continued need for post-discharge dialysis. 6
• Post-discharge dialysis is associated with significantly increased mortality risk (HR 2.57). 6

Nutritional Support for Established AKI

• Provide 20-30 kcal/kg/day total energy intake for patients with any stage of AKI. 2
• Do not restrict protein intake to prevent or delay RRT initiation. 2
• Administer protein at 0.8-1.0 g/kg/day in noncatabolic AKI patients without dialysis, and 1.0-1.5 g/kg/day in patients on RRT. 2
• Provide nutrition preferentially via the enteral route. 2

Risk Factors and Prognosis

Understanding risk factors helps identify patients requiring more aggressive monitoring and intervention:

• Major risk factors include: abnormal baseline creatinine, in-hospital arrest location, higher number of epinephrine doses during arrest (both total doses and rate of dosing), post-cardiac arrest acidosis (pH <7.21), initial non-shockable rhythm, longer duration of arrest, presence of shock, and higher blood lactate after resuscitation. 1, 7, 3
• AKI is associated with significantly increased mortality (OR 2.63, HR 1.35) and poor neurological outcomes (OR 2.22-2.27). 6, 8, 3
• Hospital mortality is 69.4% in AKI patients versus 52.0% in non-AKI patients. 6

Follow-up Care

• Ensure early follow-up after discharge for patients with AKI, as they are at higher risk for developing chronic kidney disease. 5
• Pediatric patients should receive follow-up within 3 months post-discharge, especially those with severe AKI. 5
• At 30 days post-cardiac arrest, many survivors achieve normal kidney function (eGFR >75 mL/min/1.73 m²), particularly younger male patients. 8

Common Pitfalls to Avoid

• Avoid under-resuscitation: Inadequate fluid therapy guided only by conventional monitoring increases AKI risk compared to hemodynamic-guided approaches. 4
• Avoid nephrotoxic medication exposure: This is a modifiable risk factor that requires vigilant attention in the post-arrest period. 1, 2
• Avoid delayed RRT initiation: Early consideration of RRT, particularly with fluid overload, may improve outcomes. 2, 5
• Avoid ignoring epinephrine dosing: Both total number and rate of epinephrine administration during arrest impact AKI risk and severity, suggesting potential epinephrine toxicity. 7