Hydromorphone as an adjuvant induction agent in reducing rocuronium induced pain and hemodynamic changes during tracheal intubation

Groups are divided according to the pretreatment drugs : (a)hydromorphone (hydromorphone group), (b) fentanyl (fentanyl group) or (c) normal saline (normal saline group) During preoxygenation with 100% oxygen, the study drug was injected over 30 sec and an investigator blinded to the study drug observed the signs of side effects, such as apnea or coughing, for 30 sec. The study drugs were 5 ml of either intravenous (IV) hydromorphone hydrochloride 2 mg (Dilid registered trademark, Ha Na Phram, Seoul, Korea; hydromorphone group, n = 65) or intravenous (IV) fentanyl citrate 100 microgram (Gu Ju Pharm, Seoul, Korea; fentanyl group, n = 67) or intravenous (IV) normal saline (sodium chloride, Joong Wae Pharm, Seoul, Korea; saline group, n = 62).Then 2.5% thiopental sodium 5 mg/kg was injected over 5 sec. After the loss of consciousness and eyelash reflexes, when the appropriate end tidal carbon dioxide curve appeared on capnography upon trial of mask ventilation with the fraction of oxygen ratio (FiO2) 1.0, rocuronium 0.6 mg/kg was injected over 5 sec. The time interval between the study drug injection and rocuronium injection was set to be < 90 sec in all patients. Two anesthesiologists, one who administered the study drug and another to conduct the anesthetic induction, assessed the patient response during and immediately after rocuronium injection in a double-blinded manner. The two investigators were educated beforehand to grade the patient response according to the scale proposed by Shevchenko and colleagues 12: 1 = no movement, 2 = movement at the wrist only, 3 = movement/withdrawal involving the arm only (elbow/shoulder), 4 = generalized response, withdrawal or movement in more than one extremity. Sevoflurane was started after the rocuronium injection and was adjusted to maintain an end-tidal concentration of 2.5-3.0 vol% in 100% oxygen. Two minutes after the rocuronium injection, the anesthesiologist who had more than 4 years’ experience of anesthetic practice performed tracheal intubation and applied controlled ventilation in order to maintain normocarbia without ballooning the cuff for 1 min to avoid stimulation. The patient movement and the status of vocal cord relaxation were observed during tracheal intubation. Anaesthesia was maintained with sevoflurane (end-tidal concentration of 2-3 vol%). The time interval between the study drug injection and intubation was designed to be within three to four minutes in all patients. The intubation time, which was defined as the time from mouth opening to obtaining the appropriate capnographic trace, was measured in all patients. The mean arterial pressure and heart rate were measured upon arrival at the operating room, 1 min before and after tracheal intubation. If there was an increase of heart rate (> 40% in baseline) and/or increased blood pressure with ST change in electrocardiogram after intubation, the administration of IV esmolol (0.3 mg/kg) was available.