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FOCUS POINTS
The increased metabolic rate of children comparing to adults requires a different selection of vasoactive drugs to restore and maintain the oxygen delivery to the tissues and support the circulation during periods of stress or sepsis.
Phenylephrine has a very narrow therapeutic spectrum in the pediatric population, mostly limited for patients with tetralogy of Fallot (TOF) and hypertrophic obstructive cardiomyopathy (HOCM)
Milrinone is used in pediatric patients with congenital heart disease, cardiomyopathy, and heart failure and in patients with increased pulmonary vascular resistance (PVR).
Dopamine is still used to improve tissue perfusion and urine output in neonates and premature infants.
Newborn myocardium contractility depends significantly on serum calcium levels. Hypocalcemia needs to be promptly identified and corrected.
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SYMPATHOMIMETIC DRUGS, INOTROPES, AND VASOACTIVE DRUGS
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Epinephrine is an endogenous catecholamine that is being produced and secreted in the blood stream by the adrenal medulla after direct stimulation from sympathetic efferent fibers. It combines with pre- and postsynaptic adrenergic receptors in the periphery to generate a stress response. Epinephrine has more pronounced β1 and β2 receptor effect and less α1 and α2 effect. It produces a positive inotropic and chronotropic effect on the heart and causes splanchnic vasoconstriction and vasodilation of the skeletal muscle vascular bed in order to facilitate the flight or fight response. Additionally, it increases gluconeogenesis and glycogenolysis, supplying the body with the nutrients to meet the high metabolic demands associated with the stress state. As a β1-agonist, it is a very effective bronchodilator.
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In clinical practice, epinephrine is used as an infusion for patients with left ventricular systolic dysfunction or right heart failure in order to increase the oxygen delivery to the body. It increases the oxygen consumption of the myocardium, which can be a limitation on its use for older adult patients with coronary artery disease. The absence of coronary artery disease in the pediatric population makes epinephrine the choice of preference.
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The infants and children have high metabolic demands with an oxygen consumption of 10 to 14 mL/kg for infants dropping to 5 to 7 mL/kg after the first year. The oxygen demand increases even more in critically ill or septic patients, and a pharmacologic support that increases the cardiac output helps the cardiovascular system meet this demand.1,2
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Most common uses of epinephrine in pediatric patients are as follows:
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Sepsis and hypotension in the ICU: Epinephrine is the first drug of choice for critically ill patients with a wide range of doses. The effects of the treatment on the oxygen delivery can be indirectly assessed by measuring the blood pressure or directly measured by the mixed venous saturation (SvO2) or using NIRS (near-infrared spectroscopy). When the pharmacological treatment fails, patients may require extracorporeal membrane oxygenation (ECMO) support. Most of these patients have been on high doses ...