In this randomized clinical trail, 104 patients who are candidated for elective surgery under general anestheis and tracheal intubation will be enrolled.Inclusion criteria:
ASA physical status 1 or 2, Mallampati classification 1 or 2 , Aged between 18 and 60
Baseline BP less than 140/90 , Patients without history of difficult intubation or laryngoscopy , Patients without history of cardiovascular disease, hypertension, diabetes, pulmonary, and other systemic disease as well as cervical spine disease, and GERD , Patients without difficult laryngoscopy or intubation , Body mass index ≤ 30 , without consumption of any drugs effective on blood pressure or heart rate (e.g. betablocker or calcium channel blockers)
Exclusion criteria:
Patients failed to be ventilated by face mask following induction of anesthesia , Decrease more than 25% in heart rate (HR) and blood pressure (BP) after induction of anesthesia , Decrease in O2 saturation to ≤ 94% during ventilation or intubation , Cormack and Lehane score more than 2 at laryngoscopy , Failed intubation attempt which defined as patients requiring more than one attempt to achieve successful intubation, intubations that require more than 30s to be performed and also need for another person to complete the procedure.
All laryngoscopy and intubation procedures will be performed by a single investigator in year 3 of residency.Premedication,oxygenation and then induction of anesthesia will be performed as the same in both groups. one group will be intubated by mackintash laryngoscop and the other group by glidescop(video laryngoscop). Heart rate , systolic and diastolic blood pressure will be recorded at different times before and after intubation. Also thetime need for intubation between 2 groups will be measured and compared.