The objective of this study was to investigate whether the α agonist dexmedetomidine has the ability to attenuate hypoxemia in pediatric patients undergoing palliative pulmonary artery reconstruction.From January 2009 to January 2013, a total of 25 pediatric patients with Tetralogy of Fallot, pulmonary atresia (ventricular septal defect), or persistent truncus arteriosus (I) were enrolled in our study. Due to hypoplastic pulmonary arteries, all patients received palliative pulmonary artery reconstruction. During the perioperative period, they were allocated to receive either dexmedetomidine (bolus dose of 0.3 μg/kg followed by an infusion of 0.2-0.3 μg/kg/h, n = 15) or control drug (n = 10) intravenously. Any desaturation was recorded. Heart rate, mean arterial pressure, pulse oximetry, and arterial blood gas parameters were measured during the perioperative period.There were no significant differences between the groups in hemodynamic variables. The arterial oxygen saturation and arterial blood gas parameters increased in the dexmedetomidine groups (P < 0.05).These findings suggest that the injection of dexmedetomidine can attenuate hypoxemia during palliative pulmonary artery reconstruction in pediatric patients.