Cardiac Inotrope use (paediatric)
An anaesthesia guideline on the use of inotropes for paediatric cardiac patients in PICU and OR
Inotropes - indication and dosage
Routine cases
< 3 months: Milrinone 0.5mcg/kg/min#
> 3 months: Dopamine 5mcg/kg/min
Modified Blalock-Taussig Shunt
Milrinone 0.25-0.5mcg/kg/min
Bidirectional Glenn procedure
Milrinone 0.25-0.5mcg/kg/min
Fontan procedure
Dopamine 5mcg/kg/min
+/- Milrinone 0.5mcg/kg/min
More complex surgery including Norwood /Sano*
Milrinone 0.25-0.5mcg/kg/min
+/- Adrenaline 0.05mcg/kg/min
+/- Noradrenaline 0.05mcg/kg/min
Tetralogy of Fallot repair
Milrinone 0.25-0.5mcg/kg/min
Noradrenaline 0.05mcg/kg/min
# A loading dose of milrinone will NOT be routinely given but the infusion rate may be run at a higher level for several hours initially.
* If this is inadequate then adrenaline may be increased to 0.1mcg/kg/min and noradrenaline added at a similar dose to adrenaline.
Patients who are vasoplegic, i.e. overdilated with good cardiac function but low blood pressure may require a vasopressin infusion. Start in those patients if requiring >0.1mcg/kg/min noradrenaline. Dose is 0.02-0.06U/kg/hr.
For ongoing hypotension/low CO in neonates consider a 10% calcium gluconate infusion at 0.5-1ml/hr targeting an ionised calcium level of 1.3-1.5mmol/L. DO NOT USE in older patients.
If inotropic requirements are increasing inform the cardiac surgeon and consider additional investigations (ECHO) and treatments such as opening the chest and/or mechanical support.
Rationale
Dopamine is not a good drug for infants due to increased O2 demand, interference with HPA and inhibition of hypoxic drive.
Milrinone is a good inodilator and lusitropic agent making it ideal for hearts with diastolic dysfunction but not so good for hypotensive patients.
Select the inotrope(s) required based on the underlying physiology and what you are trying to achieve.
Be prepared to alter inotropes if required.
Neonates/Infants especially can have poor cardiac function and normal or raised MAP. Do not stop inotropes for hypertension unless you are certain that cardiac function is good. If not then add in a vasodilator such as GTN or nitroprusside and continue the inotrope.