The effect of magnesium sulfate on post off-pump coronary artery bypass grafting bleeding

Magnesium level alteration may cause coagulation abnormality resulting in bleeding complication after off-pump coronary artery bypass grafting. In this study, we investigated the effect of magnesium on the postoperative coagulation profile and bleeding in OPCAB patients.

In a double blind clinical trial, six hundred patients were randomly allocated to two groups: group A (n=150) and group B (n=450). Group A received 50mg/kg of magnesium sulfate (MS) in 100ml 0.9% NaCl solution over 20min before the anesthesia induction. Group B or control group received only 100ml 0.9% NaCl solution at the same time points. OPCAB was performed with standard technique and device. Blood samples were collected 30min before and 6h after the surgery to analyze hemoglobin and blood coagulation tests. Postoperative exploration for bleeding, blood transfusion, and volume of transfusion was recorded. The two groups compared with t-test and χ(2) tests and p-valve <0.05 were considered as significant.

However, postoperative hemoglobin was statistically lower in group A compared with group B, but platelet, PT, and aPTT tests were not statistically different between two groups. The serum MS level, exploration for bleeding, volume of packed cell transfusion, and volume of postoperative bleeding were statistically different between group A vs group B.

Preoperative MS use may be associated with the postoperative platelet dysfunction and increased tendency to bleeding. This is an important risk factor for postoperative bleeding in the OPCAB in absence of CPB use.