Early extubation of children after cardiac surgery has been suggested as a safe alternative to prolonged postoperative intubation. Early extubation is an essential stage in the "fast-track" protocol. Early extubation protect against the deleterious effects of mechanical ventilation such as laryngotracheal trauma, barotrauma, pneumothorax, mucus plugging in the endotracheal tube, incorrect positioning, kinking of the tube, accidental extubation and ventilator associated pneumonia. Dexmedetomidine is a useful sedative agent with analgesic properties, hemodynamic stability and ability to maintain respiratory function in mechanically ventilated patients facilitating early weaning. Dexmedetomidine blunts the sympathetic mediated hyperdynamic response to surgical stress and attenuates the cardiovascular and neuroendocrine responses to surgery in pediatric cardiac surgery patients operated on under cardiopulmonary bypass (CPB). The stress response to CPB is characterized by the release of a large number of neurohumoral substances, including catecholamines, vasopressin, prostaglandins, cortisol, and growth hormones. This response is more extreme in the neonate than that seen in adult cardiac surgical patients. Stimuli include prolonged foreign surface contact of the bypass machine, hypothermia, low perfusion pressure, and nonpulsatile perfusion