What are the strategies for preventing and managing Acute Kidney Injury (AKI) after pediatric cardiac surgery?

Prevention and Management of Acute Kidney Injury After Pediatric Cardiac Surgery

Early identification of risk factors and implementation of preventive strategies are essential for reducing the incidence and severity of acute kidney injury (AKI) after pediatric cardiac surgery.

Incidence and Impact

• AKI complicates 22-36% of cardiac surgical procedures in children, with 11.5% developing severe AKI and 6.4% requiring renal replacement therapy (RRT) within 48 hours of return of spontaneous circulation 1
• AKI significantly increases hospital costs, morbidity, and mortality in pediatric cardiac surgery patients 1, 2
• Children with severe AKI requiring RRT or vasoactive support have significantly higher mortality rates 3, 1
• Long-term follow-up studies show that 59.1% of children who developed AKI after cardiac surgery have at least one marker of kidney injury at 5-year follow-up 4

Risk Factors

• Abnormal baseline creatinine, in-hospital arrest location, higher number of epinephrine doses during arrest, and post-cardiac arrest acidosis (serum pH <7.21) are significant risk factors 3, 1
• Younger age (<12 months), longer cardiopulmonary bypass (CPB) time, and low preoperative hemoglobin are independent risk factors for AKI 5
• Significant hemoglobin concentration increase (>3 g/dl) from preoperative levels on postoperative day 1 is strongly associated with AKI development 5
• Presence of genetic syndromes increases risk of developing chronic kidney disease after AKI 4

Prevention Strategies

Early Risk Identification

• Implement biomarker-based early detection strategies using neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, and liver fatty acid-binding protein, which increase 2-4 hours after surgery 1, 2, 6
• Kidney injury molecule-1 and interleukin-18 represent intermediate biomarkers (increasing 6-12 hours after surgery) 2
• Utilize these biomarkers to guide early intervention strategies in high-risk patients 1, 6

Medication Management

• Avoid nephrotoxic agents in at-risk patients 1
• Discontinue angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) for 48 hours post-surgery 1
• Use aminoglycosides only when no suitable alternatives are available, administering as a single daily dose with close monitoring of drug levels 1
• Adjust medication dosages for patients with impaired kidney function 1
• Low-dose dopamine is not recommended for AKI prevention or treatment 1, 7

Fluid Management

• Implement goal-directed fluid therapy using standardized algorithms with quantified goals for blood pressure, cardiac index, systemic venous oxygen saturation, and urine output 1
• Use isotonic crystalloids rather than colloids for volume expansion in patients at risk of AKI 1
• Avoid starch-containing fluids in patients at risk of AKI 1
• Monitor for and prevent fluid overload, which is associated with worse outcomes in pediatric AKI 2, 8

Hemodynamic Management

• Use vasopressors in conjunction with fluids in patients with vasomotor shock 1
• When using dopamine, titrate carefully to the desired hemodynamic response, starting at 2-5 mcg/kg/min in patients likely to respond to modest increments of heart force and renal perfusion 7
• For more seriously ill patients, begin dopamine at 5 mcg/kg/min and increase gradually in 5-10 mcg/kg/min increments up to 20-50 mcg/kg/min as needed 7
• Monitor urine output closely when dopamine doses exceed 50 mcg/kg/min, and consider dose reduction if urinary flow decreases in the absence of hypotension 7
• Implement protocol-based management of hemodynamic and oxygenation parameters in high-risk perioperative settings 1
• Monitor and optimize cardiac output to ensure adequate renal perfusion 1

Other Preventive Measures

• Maintain plasma glucose between 110-149 mg/dL (6.1-8.3 mmol/L) to avoid hyperglycemia 1
• Avoid radiocontrast agents when possible in at-risk patients 1
• Consider increasing CPB flow to improve renal oxygenation during surgery 1
• Correct preoperative anemia and prevent hemoconcentration to potentially reduce AKI risk 5

Management of Established AKI

Monitoring

• Closely monitor kidney function, including urine output and creatinine 3, 1
• Monitor serum concentrations of nephrotoxic medications 3, 1
• Assess for fluid overload, which is associated with worse outcomes 2, 8

Renal Replacement Therapy

• Consider early initiation of RRT, particularly in cases with fluid overload 1
• Approximately 6.4% of children require RRT within 48 hours after cardiac arrest following cardiac surgery 3

Nutritional Support

• Provide 20-30 kcal/kg/day total energy intake for patients with any stage of AKI 1
• Do not restrict protein intake to prevent or delay RRT initiation 1
• Administer protein at 0.8-1.0 g/kg/day in noncatabolic AKI patients without need for dialysis, and 1.0-1.5 g/kg/day in patients with AKI on RRT 1
• Provide nutrition preferentially via the enteral route 1

Long-term Follow-up

• Implement long-term kidney function monitoring for all children who develop AKI after cardiac surgery 4
• Be vigilant for development of chronic kidney disease, which occurs in approximately 27.3% of children within 5 years after AKI 4
• Monitor for estimated glomerular filtration rate decline, which may occur at a rate of approximately 1.81 mL/min per 1.73 m² per year 4
• Screen for proteinuria, which is present in 40.9% of children at 5-year follow-up after AKI 4