Determination of the pharmacodynamic interaction of propofol and dexmedetomidine during esophagogastroduodenoscopy in children

Objectives: Propofol is a sedative‐hypnotic drug commonly used to anesthetize children undergoing esophagogastroduodenoscopy (EGD). Dexmedetomidine is a highly selective alpha‐2 adrenergic receptor agonist that has been utilized in combination with propofol to provide anesthesia. There is currently no information regarding the effect of intravenous dexmedetomidine on the propofol plasma concentration–response relationship during EGD in children. This study aimed to investigate the pharmacodynamic interaction of propofol and dexmedetomidine when used in combination for children undergoing EGD. Methods: A total of 24 children undergoing EGD, ages 3–10 years, were enrolled in this study. Twelve children received dexmedetomidine 1 μg·kg^?1 given over 10 min as well as a continuous infusion of propofol delivered by a computer‐assisted target‐controlled infusion (TCI) system with target plasma concentrations ranging from 2.8 to 4.0 μg·ml^?1 (DEX group). Another group of 12 children undergoing EGD also received propofol administered by TCI targeting comparable plasma concentrations without dexmedetomidine (control group). We used logistic regression to predict plasma propofol concentrations at which 50% of the patients exhibited minimal response to stimuli (EC₅₀ for anesthesia). Results: The EC₅₀ ± se values in the control and DEX groups were 3.7 ± 0.4 μg·ml^?1 and 3.5 ± 0.2 μg·ml^?1, respectively. There was no significant shift in the propofol concentration–response curve in the presence of dexmedetomidine. Conclusion: The EC₅₀ of propofol required to produce adequate anesthesia for EGD in children was unaffected by a concomitant infusion of dexmedetomidine 1 μg·kg^?1 given over 10 min.