A Comparative Study to Analyse the Effectiveness of Intravenous 50% Magnesium Sulphate and Dexmedetomidine for Attenuation of Cardiovascular Stress Response during Laryngoscopy and Endotracheal Intubation

Background: Direct laryngoscopy and endotracheal intubation is almost always associated with hemodynamic changes due to reflex sympathetic discharge as hypertension, tachycardia, predisposition to cardiac arrhythmia and increased myocardial oxygen consumption. Objectives: To compare the attenuation of cardiovascular stress responses during laryngoscopy and endotracheal intubation using intravenous 50% Magnesium sulphate and Dexmedetomidine. Methods: A prospective randomized double blind comparative study of Dexmedetomidine versus 50% Magnesium sulfate for attenuation of cardiovascular stress responses was done in sixty patients aged between 20 to 60 years of physical status ASA grade I and ASA grade II undergoing elective surgery under general anaesthesia. All patients were divided into 2 groups of 30 patients each. Group-M received 30 mg/kg of Magnesium sulphate and Group-D received 1 µg/kg Dexmedetomidine intravenous infusion ten minutes before intubation. Both the groups were observed for changes in hemodynamic parameters i.e. heart rate (HR) systolic, diastolic blood pressure and mean arterial pressure at 0, 2 and 5 minutes post intubation. Results: Statistical analysis was performed using SPSS version 20 (USA). Heart rate was increased at 0 minute that is immediately after intubation in group D by 2.86 ± 1.74 bpm ( 3.52%) from pre induction mean value, while in group M it was 12.26 ± 2.96 bpm (14.69%) ( p = 0.0001), showing highly significant difference among both the groups. Similarly at 2 minutes after intubation rise in heart rate in group D is only 0.10 ± 1.90 bpm (0.12 %) while in group M it is 5.56 ± 2.18 bpm (1.79%) showing a statistically significant difference ( p = 0.0021). At 5 minutes after intubation both groups shows mean heart rate near pre induction mean values in group D it was 78.3 ± 7.15 bpm with a decrease of 3.17 bpm (-3.89%) while in group M it was 83.30 ± 8.73 bpm with a difference of -0.20% from pre induction (p = 0.0184). Systolic blood pressure, diastolic blood pressure and mean arterial pressure remain comparable in both the groups at 0, 2 and 5 minutes after intubation i.e. statistically not significant (p > 0.05). Therefore both dexemedetomidine and MgSO4 were effective in controlling the SBP, DBP & MAP after intubation. Conclusion: Magnesium sulphate is as effective as dexmedetomidine in attenuating the cardiovascular stress response to laryngoscopy and endotracheal intubation. Dexmedetomidine (1μg/kg) provides fairly good and sustained control over hemodynamic responses to the stress of laryngoscopy and intubation and is significantly better than MgSO4 (30mg/kg). So we conclude that dexmedetomidine is better alternative to MgSO4 for attenuation of stress responses of laryngoscopy and intubation.