What are the dialysis settings for a neonate on inotropes (inotropic medications) with acute kidney injury (AKI) and hemodynamic instability?

From the Guidelines

For neonates requiring sustained low-efficiency dialysis (SLED) while on inotropes, I recommend using a combination of HD or CKRt with eCmo, as it increases the patient's blood volume, enables the use of a larger cannula, and facilitates improved hemodynamic control, as suggested by the consensus panel for hybrid therapy 1.

Key Considerations

• The use of eCmo with HD or CKRt is particularly recommended in neonates who are hemodynamically unstable, have rapidly deteriorating neurological status, or have moderate or severe encephalopathy 1.
• The combination of HD or CKRt with eCmo can help to rapidly clear ammonia and improve hemodynamic stability, but it also carries an increased risk of causing a substantial cerebrovascular event, particularly in low-birth-weight neonates 1.

Dialysis Settings

• Blood flow rate: 3-5 mL/kg/min
• Dialysate flow rate: 300-500 mL/hour
• Small surface area dialyzer (0.02-0.1 m²) appropriate for the neonate's weight
• Ultrafiltration: begin conservatively at 1-2 mL/kg/hour to avoid hemodynamic instability
• Anticoagulation: minimal or avoided if possible; if needed, use regional citrate at 2-3 mmol/L or heparin at 5-10 units/kg/hour, as suggested by the KDIGO guidelines 1

Monitoring and Adjustments

• Monitor vital signs every 15-30 minutes, with continuous blood pressure monitoring
• Adjust inotrope doses as needed to maintain hemodynamic stability, typically increasing doses by 10-20% at initiation of dialysis
• Frequent assessment of electrolytes (every 2-4 hours initially) is essential, with particular attention to calcium, potassium, and phosphate levels
• The dialysate should contain sodium 140 mEq/L, potassium 3-4 mEq/L, calcium 2.5-3.5 mEq/L, and bicarbonate 30-35 mEq/L, as recommended by the KDIGO guidelines 1

From the Research

Dialysis Settings for Neonates on Inotropes

• The optimal dialysis settings for neonates on inotropes are not well-established, but studies suggest that peritoneal dialysis can be effective in this population 2.
• A study published in 2008 found that peritoneal dialysis creatinine clearance was not correlated with inotrope or vasopressor infusion in neonates after cardiac surgery 2.
• Another study published in 2018 highlighted the challenges of hemodialysis in neonates and infants, including high risks of mortality due to small blood flow volumes 3.

Inotrope Selection for Neonates

• The choice of inotrope for neonates is complex and depends on various factors, including the underlying condition and hemodynamic status 4.
• A study published in 2006 suggested that inotropes that reduce afterload, such as dobutamine, may be more appropriate in the transitional period, while those with more vasoconstrictor actions, such as dopamine, may be more appropriate later on 4.
• More recent studies have investigated the effects of different inotropes on renal function, with some suggesting that levosimendan may have renoprotective effects compared to other inotropes 5.

Considerations for Dialysis in Neonates on Inotropes

• The use of vasopressin in neonates on continuous renal replacement therapy (CRRT) has been associated with higher odds of adverse kidney outcomes, although earlier initiation may be beneficial 6.
• The optimal timing and dose of vasopressin in this population are not well-established and require further study 6.
• The selection of inotrope therapy should take into account the potential effects on renal function, as well as other factors such as hemodynamic status and underlying condition 5.