ABSTRACT
OBJECTIVE: To compare the effects of propofol and ketamine on systemic and pulmonary circulations in pediatric patients scheduled for elective cardiac catheterization. DESIGN: Prospective, randomized, and blinded. SETTING: University hospital. PARTICIPANTS: Children (n = 41) undergoing cardiac catheterization. INTERVENTIONS: All children were premedicated with oral midazolam 60 minutes before the procedure. Patients were separated into 3 groups according to shunts diagnosed by transthoracic echocardiography before the catheterization procedure: patients without cardiac shunt (Group I, n = 11), left-to-right shunt (Group II, n = 12), and right-to-left shunt (Group III, n = 18). A continuous infusion of propofol (100-200 microg/kg/min) or ketamine (50-75 microg/kg/min) was randomly started in all groups to obtain immobility during the procedure. Hemodynamic data, including systemic venous, pulmonary artery and vein, aortic saturations and pressures, were recorded; Qp/Qs were calculated. The same set of data was recorded before discontinuation of infusions at the end of the procedure. MEASUREMENTS AND MAIN RESULTS: After the propofol administration, in all 3 patient groups propofol infusion was associated with significant decreases in systemic mean arterial pressure. In groups with cardiac shunts (Group II and III), propofol infusion significantly decreased systemic vascular resistance and increased systemic blood flow, whereas pulmonary vascular resistance and pulmonary blood flow did not change significantly. These changes resulted in decreased left-to-right shunting and increased right-to-left shunting; the pulmonary-to-systemic flow ratio decreased significantly. On the other hand, after ketamine infusion, systemic mean arterial pressure increased significantly in all patient groups, but pulmonary mean arterial pressure, systemic vascular resistance, and pulmonary vascular resistance were unchanged. CONCLUSION: In children with cardiac shunting, the principal hemodynamic effect of propofol is a decrease in systemic vascular resistance. In children with intracardiac shunting, this results in an increase in right-to-left shunting and a decrease in the ratio of pulmonary to systemic blood flow, which may lead to arterial desaturation. Ketamine did not produce these changes. The authors suggested that during cardiac catheterization in children, both the anesthesiologists and cardiologists need to know that anesthetic agents can significantly alter the hemodynamic status in children with complex congenital heart defects and affect the results of hemodynamic calculations that are important for decision-making and treatment of these patients.