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Hemodynamic effects of dobutamine after cardiopulmonary bypass in children
Insights
Dobutamine effectively increases cardiac output in children post-heart surgery but causes significant heart rate increases. This tachycardia may limit its use in pediatric patients after cardiopulmonary bypass.
Area of Science:
- Pediatric Cardiology
- Pharmacology
- Critical Care Medicine
Background:
- Dobutamine is a synthetic inotropic agent known to increase cardiac output in adults.
- Its efficacy and safety in pediatric patients after congenital heart disease surgery require further investigation.
Purpose of the Study:
- To evaluate the effects of dobutamine infusion on cardiac function and hemodynamics in children after cardiopulmonary bypass.
- To determine the optimal dosage and assess potential side effects in this population.
Main Methods:
- Eleven pediatric patients undergoing surgical correction of congenital heart disease received dobutamine infusions at escalating doses (1, 4, 7, and 10 micrograms/kg x min).
- Hemodynamic parameters including cardiac index, heart rate, blood pressure, stroke volume, and peripheral vascular resistance were monitored.
Main Results:
- Dobutamine significantly increased cardiac index at doses of 4, 7, and 10 micrograms/kg x min (23%, 23%, and 16% respectively).
- Significant increases in heart rate (up to 47% in one patient) and blood pressure were observed.
- Infusion discontinuation was necessary in 4 subjects due to excessive tachycardia.
Conclusions:
- Dobutamine acts as an effective inotropic agent in children, primarily through beta-1 receptor stimulation, leading to a chronotropic effect.
- The drug can cause significant tachycardia in pediatric patients, potentially reaching unacceptable levels and limiting its use post-cardiopulmonary bypass.
Abstract:
The synthetic inotropic agent, dobutamine, has reportedly increased cardiac output in adults after cardiopulmonary bypass with minimal side effects. Its use in children, after surgical correction of congenital heart disease, was tested by infusing the drug at 1, 4, 7, and 10 micrograms/kg x min in 11 children. While significant increases in cardiac index above control (23, 23, and 16% at 4, 7, and 10 micrograms/kg x min, respectively) were observed, this was achieved at the expense of significant increases in heart rate (15, 24, and 10%). This increase in heart rate (47% in one child) necessitated discontinuing the infusion in 4 subjects. There were also significant increases in systolic and mean blood pressure with no change in stroke volume or peripheral vascular resistance. The authors conclude that in children, dobutamine is an effective inotropic agent acting principally by stimulating beta 1-receptors in the myocardium producing a predominantly chronotropic effect without significant changes in peripheral vascular resistance. Given the intrinsically higher heart rate of children, the levels of tachycardia produced by the drug in some instances reach unacceptable levels and as such, may make dopabutamine unsuitable for use in children after cardiopulmonary bypass.