Fentanyl and Propofol for Tracheal Intubation During Sevoflurane Induction Without Muscle Relaxants in Children

All patients fasted 6 h for solid food, but clear fluids will be given for up to 4 h pre- operatively. All patients will be pre-medicated with 0.3 mg/kg oral midazolam (maximum dose of 12 mg) 30 min before induction and EMLA cream will be applied to the dorsum of both hands 1 h prior to surgery. Children who refuse to take oral premedication will be excluded. One parent will be allowed to accompany the child into the pre-operative holding area. On arrival in the anesthetic room, baseline heart rate, pulse oximeter oxygen saturation and non-invasive blood pressure will be measured. A side-stream connector for the measurement of end-tidal sevoflurane concentration and end-tidal carbon dioxide will be introduced between the face mask and a Mapelson D breathing system.

• Anesthesia will be induced by a circle system using a vaporizer concentration of 6% sevoflurane in an oxygen flow of 6 L/min. After loss of consciousness and the eyelash reflex, sevoflurane concentration will be reduced to 3 % and intravenous access will be secured in all children using a 22-G cannula sited on the dorsum of a hand and the facemask ventilation will be then assisted using a 10 cm H2O inspiratory pressure at a ventilatory frequency of 16min. Once IV cannula is administered the inspired concentration of sevoflurane was decreased to 1% in oxygen.
• The investigating anesthetist will open a sealed envelope allocating the patient to one of two groups: Group 1 = fentanyl 2 μg/kg and propofol 2 mg/kg or Group 2 = fentanyl 2 μg/kg and propofol 3 mg/kg. Both test drugs will be made up to 10 ml with saline. In both groups, fentanyl will be first administered intravenously over 30 s followed by propofol over 20 s.
• Ninety seconds after administration of propofol, laryngoscopy and tracheal intubation with an appropriate sized non cuffed tube will be performed using a suitable sized Macintosh laryngoscope by a second an experienced unbiased anesthetist who enters the room and, unaware of the patient's randomization group. Intubating conditions will be evaluated as proposed by Viby-Mogensen and colleagues [9]. Five factors will be considered for assessment, jaw relaxation; ease of laryngoscopy; vocal cord position; coughing; and patient movement as excellent (1), good (2) or poor (3).
• Overall intubating conditions will be recorded as 'excellent' if all score 1, 'good' if any scored 2, and 'poor' if there will be any scores of 3. Intubation will not be attempted if the vocal cords is closed to avoid airway complications and any failure to intubate the trachea or prolonged coughing on intubation will be managed using suxamethonium or a non-depolarising muscle relaxant where clinically indicated.
• Following successful tracheal intubation, the study will be ended at this point, ventilation will be gently assisted and anesthesia will be maintained at the discretion of the anesthesiologist. In both groups HR, MAP and SPO2 will be measured immediately before the inhaled induction, after propofol administration, prior to intubation, immediately after intubation and at 2 and 5min min after intubation. Occurrence of bradycardia, hypotension or other significant complication will be recorded.
• The first investigating anesthetist is unblinded and responsible for preparing and administering all drugs. The second anesthetist will be blinded to drug allocation, intubate patients, record all parameters, and grade the airway conditions