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Magnesium substitution in elective coronary artery surgery: a double-blind clinical study
J O Wistbacka1, J Koistinen, K E Karlqvist
1Department of Anesthesiology, Oulu University Central Hospital, Finland.
Insights
High-dose magnesium may help control arrhythmias after coronary artery bypass graft (CABG) surgery. This study compared high-dose versus normomagnesemic magnesium regimens to assess their effects on postoperative arrhythmias.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Clinical Pharmacology
Background:
- Postoperative arrhythmias are a common complication following coronary artery bypass graft (CABG) surgery.
- Magnesium's role in managing these arrhythmias is recognized, but optimal dosing strategies remain unclear.
- The efficacy of high-dose magnesium compared to maintaining normomagnesemia requires further investigation.
Purpose of the Study:
- To compare the effects of two different magnesium infusion regimens on electrolyte balance.
- To assess the impact of high-dose versus normomagnesemic magnesium on postoperative arrhythmias in CABG patients.
- To evaluate the safety and efficacy of magnesium supplementation in the perioperative period of cardiac surgery.
Main Methods:
- Prospective, randomized, double-blind clinical trial involving 81 elective CABG patients.
- Two magnesium regimens were administered: a high-dose group (H) and a low-dose (normomagnesemic) group (L).
- Continuous Holter monitoring was used for 12-15 hours preoperatively and 48 hours postoperatively to detect arrhythmias.
Main Results:
- Serum magnesium levels peaked in the high-dose group on the first postoperative morning (1.60 +/- 0.25 mmol/L).
- Patients in the low-dose group remained normomagnesemic, except briefly after cardiopulmonary bypass initiation.
- The study aimed to determine if high-dose magnesium offers superior control of arrhythmias compared to maintaining normal magnesium levels.
Conclusions:
- The study provides data on magnesium levels and electrolyte balance in CABG patients receiving different magnesium regimens.
- Further analysis is needed to correlate these findings with the incidence and severity of postoperative arrhythmias.
- The findings contribute to understanding magnesium's role in preventing cardiac arrhythmias after CABG surgery.
Abstract:
Magnesium may be beneficial in the control of ventricular ectopy and supraventricular tachyarrhythmias after coronary artery bypass graft (CABG) surgery, but it is not known whether a high-dose magnesium regimen is superior to a regimen keeping the patient normomagnesemic. A prospective randomized and double-blind clinical comparison was performed in 81 elective CABG patients in order to assess the effects of two different magnesium infusion regimens on electrolyte balance and postoperative arrhythmias. Forty-one patients (high-dose group, H) received 4.2 +/- 0.7 g (mean +/- SD), of magnesium sulfate before cardiopulmonary bypass, followed by an infusion of 11.9 +/- 2.8 g of magnesium chloride until the first postoperative (PO) morning, and a further 5.5 +/- 1.0 g until the second PO morning. Forty patients (low-dose group, L) received magnesium sulfate only after bypass to a total of 2.9 +/- 0.5 g at the first, and 1.4 +/- 0.1 g at the second PO morning. A blood cardioplegia technique was used in both groups, including bolus doses of magnesium chloride to a total of 2.4 +/- 0.6 g and 2.3 +/- 0.6 g to H and L patients, respectively. Continuous Holter tape-recording was used for 12 to 15 hours preoperatively, and for 48 hours postoperatively. Serum magnesium peaked in H patients on the first PO morning at 1.60 +/- 0.25 mmol/L, whereafter it declined to the normal level on the third PO morning. Patients in the L group were normomagnesemic, except after the start of bypass.(ABSTRACT TRUNCATED AT 250 WORDS)