Methylene Blue in the Assessment of Gain In Cardiac Surgical Post-Operative vasoplegia (MAGIC) trial

Nitric oxide is a chemical released from blood vessel walls and causes vasodilation and low blood pressure known as vasodilatory shock. Vasodilation by this mechanism often occurs in patients who undergo surgeries which need heart lung bypass such as cardiac surgery and can be resistant to normal blood pressure supporting medications. This condition is called vasoplegia. In such patients, methylene blue, which is a common drug that opposes nitric oxide-induced effects on blood vessels may potentially provide a mechanism to reduce the need for blood pressure support in patients having cardiac surgery. Only one previous randomised controlled trial has evaluated the use of methylene blue in patients with post cardiac surgery vasoplegia. A total of 638 patients were screened with 56 who developed post cardiopulmonary vasoplegia included in the trial. Of these, 28 received an infusion of 1.5 mg/kg of methylene blue over 1 hour and 28 received placebo. Mortality was 0% for the methylene blue group and 21.4% in the placebo group. There was also a significant difference in the duration of blood pressure support with all patients in the methylene blue group being successfully weaned from support within 4 hours of the treatment. These results are suggestive of a significant benefit to the routine use of Methylene blue in this group. The objective of the MAGIC trial is to test the hypothesis is that in adults who are invasively mechanically ventilated in the ICU following cardiac surgery with clinically significant vasoplegia who are receiving high doses of blood pressure medications, does a methylene blue infusion at a rate of 1.5mg/kg/hour for one hour increase hours alive and free from blood pressure support at day 10 post randomisation when compared with placebo.