Dexmedetomidine for patients undergoing diagnostic cardiac procedures: a noninferiority study

When anesthetizing children with congenital heart disease for diagnostic cardiac catheterization, anesthesiologists and cardiologists seek to use anesthetic regimens that yield minimal hemodynamic changes and allow for spontaneous ventilations. Recently, dexmedetomidine has been used as an anesthesia adjunct because of its sedative and analgesic properties and minimal ventilatory depressive effects. We tested the hypothesis that the combination of sevoflurane and dexmedetomidine is non-inferior to sevoflurane alone as it refers to hemodynamic measurements during diagnostic cardiac catheterization in children with a transplanted heart, one ventricle (Fontan procedure), or normal cardiac physiology. Patients were anesthetized with inhalation of sevoflurane in nitrous oxide/oxygen and, after baseline hemodynamic measurements, successive boluses of dexmedetomidine followed by continuous infusion were administered. In this study, non-inferiority was shown when differences at steady-state (dexmedetomidine + sevoflurane) compared to baseline (sevoflurane alone) and its associated 95% confidence interval fell completely within the range of plus or minus 20%. Forty-one (26 normal physiology, 9 cardiac transplantation, and 6 Fontan) patients were enrolled. Non-inferiority of sevoflurane + dexmedetomidine compared with sevoflurane alone was shown for heart rate, but not for arterial blood pressure in patients with normal and cardiac transplant physiology. In patients with normal cardiac physiology, non-inferiority was demonstrated for bispectral index. Therefore, while the lack of depressive respiratory effects and non-inferiority for heart rate are desirable, the lack of non-inferiority of dexmedetomidine + sevoflurane combination for arterial blood pressure do not justify the routine use of this combination compared with sevoflurane alone for children with congenital heart disease undergoing cardiac catheterization.