A Dose – Response Study of Magnesium Sulfate in Suppressing Cardiovascular Responses to Laryngoscopy & Endotracheal Intubation

K Montazeri, M Fallah


Background: The effects of pretreatment with magnesium on cardiovascular responses associated with intubation have been studied previously. In this study we wanted to find optimal dose of magnesium that causes decreased cardiovascular responses after laryngoscopy & endotracheal intubation.
Methods: In a double-blind , randomized, clinical trial ,120 ASA-1 patients with ages between 15-50 years old , who were candidates for elective surgery, were selected and classified in 6 groups (20 patients in each ). The pulse rate and arterial blood pressure were measured and recorded at 5 minutes before taking any drug then, according to different groups, patients took magnesium sulfate (10, 20, 30, 40, 50mg/kg) and lidocaine (1.5 mg/kg). The induction of anesthesia was same in all groups and the pulse rate and arterial blood pressure were measured and recorded just before intubation and also at 1, 3 , and 5 minutes after intubation (before surgical incision ). Statistical analysis was performed by use of ANOVA, Post Hoc test (Duncan), Pearson correlation, and Chi square test.
Results: there were no statistically significant differences in blood pressure, pulse rate, Train Of Four (TOF), and complications between groups who received magnesium but the significant differences in these parameters were seen between magnesium and lidocaine groups.
Conclusion: We concluded that pretreatment with different doses of magnesium sulfate have a safe decreasing effect on cardiovascular responses that is more effective than pretreatment with lidocaine.
Keywords: magnesium sulfate, cardiovascular responses, lidocaine.

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