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

Prevention and Management of Acute Kidney Injury in Pediatric Patients After Cardiac Surgery

Biomarkers should be used for early identification of AKI risk in pediatric cardiac surgery patients, followed by implementation of a comprehensive intervention strategy including avoidance of nephrotoxic agents, discontinuation of ACE inhibitors/ARBs, close monitoring of renal function, and goal-directed fluid therapy to reduce AKI incidence and improve outcomes. 1

Incidence and Impact of AKI

• 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 (ROSC) 1
• AKI significantly increases hospital costs, morbidity, and mortality in pediatric cardiac surgery patients 1
• Children with severe AKI requiring RRT or vasoactive support have significantly higher mortality rates 1

Risk Factors for AKI After Pediatric Cardiac Surgery

• Abnormal baseline creatinine 1
• In-hospital arrest location 1
• Higher number of epinephrine doses during arrest 1
• Post-cardiac arrest acidosis (serum pH <7.21) 1
• Cardiopulmonary bypass (CPB) exposure 1

Prevention Strategies

Early Risk Identification

• Use urinary biomarkers (tissue inhibitor of metalloproteinases-2 and insulin-like growth factor-binding protein 7) to identify patients at risk for AKI as early as 1 hour after CPB 1
• Implement biomarker-guided intervention strategies, which have been shown to reduce subsequent AKI in randomized trials 1

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, less nephrotoxic alternatives are available 1
• If aminoglycosides are necessary, administer as a single daily dose rather than multiple doses and monitor drug levels closely 1
• Adjust medication dosages for patients with impaired kidney function 1

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
• Consider early placement of peritoneal dialysis catheters for passive drainage or dialysis in high-risk infants 2, 3, 4
• Prophylactic peritoneal drainage has been shown to improve fluid output (48.8 mL/kg increased output over POD 1-5) with reduced need for diuretics in complex cases 5

Hemodynamic Management

• Use vasopressors in conjunction with fluids in patients with vasomotor shock 1
• 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

• Avoid hyperglycemia and maintain plasma glucose between 110-149 mg/dL (6.1-8.3 mmol/L) 1
• Avoid radiocontrast agents when possible in at-risk patients 1
• Consider increasing CPB flow to improve renal oxygenation during surgery 1

Management of Established AKI

Monitoring

• Closely monitor kidney function, including urine output and creatinine 1
• Monitor serum concentrations of nephrotoxic medications 1

Renal Replacement Therapy

• Consider early initiation of RRT, particularly in cases with fluid overload 1, 2, 3
• Peritoneal dialysis is often the preferred modality for infants after cardiac surgery and has been shown to be safe and effective 2, 3, 4
• Early peritoneal dialysis has been associated with improved outcomes including negative fluid balance, lower vasoactive medication needs, shorter duration of mechanical ventilation, and decreased mortality 2

Nutritional Support

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

Medications Not Recommended

• Diuretics should not be used to prevent AKI but may be used to manage volume overload 1
• Low-dose dopamine is not recommended to prevent or treat AKI 1
• Fenoldopam is not recommended to prevent or treat AKI 1
• Atrial natriuretic peptide is not recommended to prevent or treat AKI 1
• Recombinant human IGF-1 is not recommended 1
• Perioperative corticosteroids have not been shown to significantly improve clinical outcomes including AKI, and may increase blood glucose and need for insulin therapy 6

Common Pitfalls and Caveats

• Risk scoring systems for AKI after cardiac surgery have good discrimination for low-risk groups but poor discrimination for moderate to high-risk patients; therefore, all patients may benefit from preventive strategies 1
• Fluid overload is a major determinant of morbidity in infants after cardiac surgery; early management of fluid balance is crucial 2, 3
• There is currently no single medication or therapy proven effective for prevention or treatment of AKI in this population; a multi-modal approach is necessary 3, 4