Oral magnesium supplementation reduces the incidence of gastrointestinal complications following cardiac surgery: a randomized clinical trial

Gastrointestinal complications are common after coronary artery bypass graft surgery. These complications are ranged from nausea and vomiting to mesenteric ischemia and liver failure. It seems that nausea, vomiting, and constipation are related to magnesium deficiency. This study was designed to examine the effect of oral magnesium supplementation on the incidence of gastrointestinal complications in patients undergoing cardiac surgery. In a single blinded randomized clinical trial, 102 patients who were undergoing coronary artery bypass graft surgery were randomly allocated into two groups, 52 patients in the intervention and 50 patients in control group. Patients in the experimental group received 800 milligram magnesium oxide (2 tablets each of them containing 240 mg elemental magnesium) daily from the admission to discharge from hospital. The incidence of post-operative nausea and vomiting, constipation, and atrial fibrillation was compared between the groups. Our results showed that postoperative hypomagnesemia is present in 41.20 and 70.80 percent of the patients in the intervention and control group patients, respectively. The overall incidence of constipation was 62%. Patients who received magnesium supplementation experienced less atrial fibrillation, nausea, vomiting, and constipation. Our data showed that oral magnesium supplementation could reduce the postoperative complications. Despite the better status in the intervention group, the hypomagnesemia was present in many of intervention group patients. It seems that supplementation with higher doses is needed.