A clinical study to evaluate the role of preoperative dexmedetomidine on attenuation of haemodynamic response to direct laryngoscopy and tracheal intubation

After approval of protocol by Institutional Ethics Committee and written informed consent, 80 adult patients of ASA (American Society of Anesthesiologists) physical status I /II of either sex, in the age group of 18 to 60 years who were scheduled to undergo elective surgery under general anaesthesia requiring tracheal intubation were included in the study. Using computer generated number table, patients were randomly divided into two groups of 40 each. Patients were allocated to one of the following group using sequentially numbered, sealed, opaque envelopes. Group I patients received dexmedetomidine, 0.5 microgram per kg i.v over 10 min and Group II patients received an equal volume of normal saline i.v over 10 min. After intubation anaesthesia was maintained with 33% of O2, 67% N2O and propofol infusion @ 50-80 microgram/kg/min. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), oxygen saturation (SpO2) , end tidal carbon dioxide (EtCO2)were continuously monitored and recorded at baseline, after completion of infusion of study drug, 5 min after completion of infusion of study drug, after induction, just before intubation, after intubation at 1 min, 3 min, 5 min, 10 min and 15 min. After recording the observations for 15 minutes, the rest of the anaesthetic procedure was carried out at the discretion of the attending anaesthesiologist. During study, the total dose of propofol required for induction was recorded. The side effects of the study drugs, if any, were also recorded. All the observations were recorded in the proforma attached and analyzed statistically using appropriate statistical test. Normality of data were checked by measures of skewness and kolmogorov smirnov tests. For normally distributed data students t- tests and for skewed data Mann Whitney U tests was applied for two groups. For time dependent changes, repeated measure ANOVA was applied. Data was presented as mean+-SD with p<.05 as significant.