Anzer Shah M.1 , Antony K.A.2
BACKGROUND Sympathetic system overactivity can result from direct laryngoscopy and intubation in general anaesthesia. This is often associated with tachycardia, hypertension, and arrhythmias and can rarely result in ischemia in susceptible individuals. Similar hemodynamic effects can result from surgical stimulation also. Deep plane of anaesthesia, intravenous opioids, beta blockers, lignocaine, dexmedetomidine, clonidine, alpha blockers, etc. are different techniques used to prevent this. There are many studies comparing various techniques but similar studies for comparing equal doses (1 mcg/Kg) of intravenous clonidine and dexmedetomidine are few. METHODS After obtaining institutional ethical committee clearance, a prospective observational study among 66 ASA class I and II patients was conducted and distributed among two groups with 33 in each, undergoing thyroidectomy under general anaesthesia. Patients were enrolled into two groups. The clonidine group received 1 mcg/Kg intravenous clonidine and the dexmedetomidine group 1 mcg/Kg intravenous dexmedetomidine as an infusion over 15 minutes before induction of general anaesthesia. The hemodynamic response to direct laryngoscopy and intubation, surgical incision and extubation as measured by the change in heart rate and blood pressure which were monitored in the perioperative period. At the end, duration of analgesia defined as the time of start of induction of general anaesthesia to the time of first request for rescue analgesic, or VAS (Visual Analogue Scale)= 40 mm were documented. The incidence of side effects, such as hypotension, bradycardia, were also monitored. All statistical analyses were carried out using the software Statistical Package for the Social Sciences (SPSS) Statistics version 19.0.0 with the help of a professional statistician. Data was expressed in its frequency and percentage as well as mean and standard deviation. RESULTS Analysis of the monitored data shows that patients in the dexmedetomidine group had more stable hemodynamic effects to direct laryngoscopy, intubation and surgical incision. The duration of analgesia of both the clonidine and dexmedetomidine were similar and did not show any significant statistical difference. Both the groups of patients had few cases of side effects like hypotension and bradycardia which were neither clinically nor statistically significant and these were easily remediable. CONCLUSIONS Use of dexmedetomidine is preferred to clonidine as intravenous premedication at 1 mcg/Kg dose.
