THE EFFECT OF MAGNESIUM-SULFATE ON HEMODYNAMICS AND ITS EFFICACY IN ATTENUATING THE RESPONSE TO ENDOTRACHEAL INTUBATION IN PATIENTS WITH CORONARY-ARTERY DISEASE

Laryngoscopy and endotracheal intubation may produce adverse hemodynam ic effects. Magnesium has direct vasodilating properties on coronary a rteries and inhibits catecholamine release, thus attenuating the hemod ynamic effects during endotracheal intubation. We studied 36 patients with coronary artery disease (CAD) scheduled for elective coronary art ery bypass grafting to evaluate the hemodynamic effects of magnesium a nd its efficacy in attenuating the response to endotracheal intubation . Patients received either 0.1 mL/kg (50%) magnesium sulfate (50 mg/kg ) (Group AI n = 19) or isotonic sodium chloride solution (Group B, n = 17) before the induction of anesthesia and 0.05 mL/kg of isotonic sod ium chloride solution (Group A) or lidocaine 2% (1 mg/kg) (Group B) be fore intubation. The hemodynamic variables were recorded before induct ion, after the trial drug, after induction, and after endotracheal int ubation. Automatic ST segment analysis was performed throughout the st udy period. Magnesium sulfate administration was associated with incre ased cardiac index (P < 0.01), a minimal increase in heart rate, and a significant decrease in mean arterial pressure (MAP) and systemic vas cular resistance (SVR) (P < 0.001). None of the patients in the magnes ium group had significant ST depression compared with three patients i n the control group. The magnesium group patients had a significantly lesser increase in MAP (P < 0.05) and SVR (P < 0.01) compared with the control group patients who received lidocaine before endotracheal int ubation. Thus, magnesium is an useful adjuvant to attenuate endotrache al intubation response in patients with CAD. Implications: Endotrachea l intubation produces adverse hemodynamic effects, which may be more d etrimental in patients with coronary artery disease than in healthy pa tients. The present study shows that magnesium administered before end otracheal intubation can attenuate this response better than lidocaine .