Comparison of the effects of lidocaine and magnesium sulfate on hemodynamic response to intubation and qt dispersion given prior to induction in hypertensive patients

The aim of this study was to investigate the effects of lidocaine and magnesium sulfate on hemodynamic response to intubation and QT dispersion given prior to induction.Following approval from the local ethics committee and written informed consent for study participation was obtained, 60 patients with a story of hypertension and regulated blood pressure, aged between 18 and 65 years, ASA status of I-II, scheduled for elective surgery, mallampati score I-II were included in the study. Patients with severe cardiac, hepatic, renal disorder and unregulated blood pressure were excluded from the study. Patients were also excluded if there was any history of allergy to drugs used in study. Patients where intubation took more than 30 seconds were excluded from study.Patients were randomly divided into 3 groups (all n=20). Before the induction of anaesthesia, the patients of magnesium sulphate group (Group-M) received magnesium sulphate 10 mg/kg whereas patients in lidocaine group (Group-L) received lidocaine 1 mg/kg in isotonic sodium chloride and total volume was adjusted to 15 ml. Patients in control group (Group-K) received 15 ml volume of isotonic sodium chloride. Anaesthesia was induced with propofol 2 mg/kg in all patients. After induction with propofol, 0,5 mg/kg rocuronium was given and then the patient?s trachea was intubated. Anaesthesia was maintained with sevoflurane 1,5%, - 2,5% in 50% N2O-O2 mixture. MAP, HR values and QT, QTc, QTd intervals were recorded at different times.There was no significant difference in HR between groups (p> 0,05). MAP values at 15 minutes after intubation were lower in Group M and L compared with the Group K (p< 0,05). When compared within groups, QT values at 1st minute were lower than the values measured at 5th minute in group M (p< 0,05). QT values were vsignificantly lower at 1st minute than the values at 5th minute and before induction in Group L and in Group K (p< 0,05). When compared within groups QTc values were higher at 1st and 5th minute in Group M (p< 0.05). And also QTd values were lower at 1st and 5th minute in Group M when compared within groups (p< 0,05). 1st minute QT value was significantly lower in Group L compared with the Group M (p< 0,05). 5th minute QT value of the Group L was significantly lower than Group M and K(p< 0,05). QTc value of Group L measured before induction was significantly lower compared with the Group K (p< 0,05) and 1st minute value of Group L was significantly lower than Group M (p< 0,05). 5th minute QTc value was significantly lower in Group L compared with the other groups 5th minute QTc values. (p< 0,05). 5th minute QTd value was significantly lower in Group M and L compared with the Group K (p< 0,05). In conclusion, magnesium applied intravenously before induction may be effective in the prevention of ventricular arrhythmias and associated complications by providing a reduction in QTd durations at the most intense periods of intubationinduced stress response.Key words: QT dispersion, hypertension, magnesium, lidocaine.