Magnesium administration and dysrhythmias after cardiac surgery. A placebo-controlled, double-blind, randomized trial.
OBJECTIVE
To determine whether magnesium administration is effective in reducing postoperative morbidity and mortality after cardiac surgery.


METHODS
Randomized, double-blind, placebo-controlled trial.


METHODS
A tertiary acute-care 500-bed university teaching hospital.


METHODS
Over a 6-month period, 100 patients electively scheduled for cardiac surgery involving cardiopulmonary bypass were studied.


METHODS
Fifty patients were randomized to receive an intravenous infusion of magnesium chloride, 2 g, and 50 patients received placebo intraoperatively after the termination of cardiopulmonary bypass.


RESULTS
Magnesium-treated patients had a significantly decreased frequency (P < .04) of postoperative ventricular dysrhythmias (eight [16%] of 50) compared with placebo-treated patients (17 [34%] of 50). Patients who were normomagnesemic postoperatively had new supraventricular dysrhythmias less frequently (P < .03) than patients who were hypomagnesemic postoperatively (eight [17%] of 48 vs 19 [37%] of 52). Compared with placebo-treated patients, magnesium-treated patients had significantly higher (P < .02) postoperative cardiac indices in the intensive care unit (2.8 +/- 0.1 vs 2.5 +/- 0.1 L/min per m2). Patients with postoperative total and ultrafilterable hypomagnesemia had postoperative ventricular dysrhythmias (P < .04) and required prolonged mechanical ventilatory support (P < .01) more frequently than patients without postoperative hypomagnesemia.


CONCLUSIONS
Total and ultrafilterable hypomagnesemia are prevalent findings in cardiac surgery patients, and postoperative hypomagnesemia is strongly associated with clinically important morbidity. Magnesium administration decreased the frequency of postoperative ventricular dysrhythmias and increased the stroke volume and thereby cardiac index in the early postoperative period.
England
M R
MR
Department of Anesthesia, New England Medical Center Hospital, Tufts University School of Medicine, Boston, Mass.
Gordon
G
G
Salem
M
M
Chernow
B
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D003627:Data Interpretation, Statistical; D004311:Double-Blind Method; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008274:Magnesium / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000187:drug effects; D013610:Tachycardia / Q000503:physiopathology / Q000517:prevention & control*
D008274:Magnesium