Aim of the study is to compare the optimal time needed for successful tracheal intubation with immediate 8% sevoflurane and incremental sevoflurane induction in surgical pediatric patients undergoing adenotonsillectomy without using muscle relaxants or opioids

Investigators studied 100 pediatric surgical patients admitted to Sulaimani Teaching Hospital in the Otorhinolaryngology, Head and Neck Surgical Department, from the first of June 2011 to the first of September 2011, Children aged 2-7 years,both genders, ASA physical statuses І and II (ASA I: a healthy normal patient, while ASA II: a patient with mild systemic disease with no functional limitations) were scheduled for elective adenotonsillectomy operations. They were randomly divided into two equal groups according to the induction method.

Group 1 (G1) using incremental induction with sevoflurane (1-8 %) in 100% O2, the vapor concentration is increased by 1% every few breaths.

Group 2 (G2) high concentration of sevoflurane (8%) in 100% O2 from the beginning of induction.

None of them is given premedication or any other adjunct drugs until successful intubation is done; ventilation was assisted and then controlled when possible. If upper airway obstruction occurred, an oropharyngeal airway was immediately inserted. Attempts were made to obtain venous access before laryngoscopy. All patients monitored with electrocardiography (ECG), noninvasive blood pressure monitoring (NIBP), pulse oximetry, and temperature measurements.

Children with extreme weight, suspicion of difficult airway, moved during laryngoscopy, or more than one trial of laryngoscopy needed were excluded from this study.

The endotracheal tube (ETT) size was selected by using the formula (age/4) + 4.5. Only a single laryngoscopy attempt was allowed. Small, brief movements of extremities occurring after (ETT) placement did not considered as exclusion criteria. Anesthesia was delivered by anesthetic machine (Datex Ohmeda), using an Ayer's T-piece with Jackson Ree's modification system, with a fresh gas flow of 6 L/min through a Sevoflurane vaporizer.

Patients were observed until eyelash reflex disappears, pupils centered and constricted. Jaw relaxation and movements were monitored. Ventilation was controlled till the time of laryngoscopy; the vocal cords were completely visible, orotracheal intubation done with Macintosh laryngoscope blade size 2 by the same anesthetist for all the patients. The time from induction until successful tracheal intubation is recorded.

Inclusion Criteria:

• Children 2-7 years old American society of anesthesiologists physical status class 1 and 2 scheduled for elective adenotonsillectomy operations

Exclusion Criteria:

• Children with extreme weight, suspicion of difficult airway, moved during laryngoscopy, or more than one trial of laryngoscopy needed