Effect of Magnesium Sulfate on Hemodynamic Changes During Sternotomy and Laryngoscopy in Coronary Artery Bypass Graft Surgery: A Randomized Clinical Trial

This study was designed to evaluate the effectiveness of low and high dose magnesium sulfate in reducing pressure responses to laryngoscopy and sternotomy.
A total of 90 patients were assigned into three groups. The patients in Group L received a 20 mg/kg bolus dose of magnesium sulfate 3 minutes before intubation followed by an infusion of magnesium sulfate (10 mg/kg/h) in contrast to 40 mg/kg of magnesium sulfate followed by an infusion
of 20 mg/kg/h magnesium sulfate administered to Group H. Patients in Group P received saline as placebo. Heart rate and mean arterial pressure (MAP) recorded at the baseline were noted down again before intubation and 30 seconds, 2 and 4 minutes after intubation and 1 minute before, and 30 seconds, 2 and 4 minutes after sternotomy.
MAP in Groups L and H compared to Group P was significantly lower, after intubation (P = 0.0040). The difference between MAP in Groups L and H was only statistically significant 30 seconds after intubation. MAP 30 seconds and 2 minutes after sternotomy was statistically different between Groups L and H compared to Group P. The difference between Groups H and P was only statistically significant before sternotomy and 4 minutes after sternotomy (P = 0.0001).
A low dose magnesium sulfate attenuates the hemodynamic response to laryngoscopy and sternotomy in coronary artery bypass graft surgery.