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Use of Dye Can Help Prevent Vasoplegic Syndrome After Cardiopulmonary Bypass: Presented at ACS

By Roberta Friedman, PhD

SAN FRANCISCO -- October 20, 2008 -- A simple preoperative injection of methylene blue, a compound used to trace lymph nodes, can avoid vasoplegic syndrome that can occur following cardiopulmonary bypass procedures, according to a study presented here at the American College of Surgeons (ACS) 94th Annual Clinical Congress.

The effect of methylene blue on vasoplegia appears to be through blockade of nitric oxide, an inflammatory mediator, said presenter Curtis Eldridge, BS, Department of Perfusion Technology, Rush University Medical Center, Chicago, Illinois, in a poster presentation on October 16.

As many as 10% of patients on cardiopulmonary bypass during coronary artery bypass grafting (CABG) or valve replacement procedures have a decrease in blood pressure and an increase in heart rate, producing vasodilation that can become unresponsive to medication to reverse it. If vasoplegia lasts longer than 36 to 48 hours, mortality can be as high as 25%, said Eldridge, who conducted the study with Anthony Perez-Tamayo, MD, PhD, Division of Cardiothoracic Surgery, Rush University Medical Center.

Eldridge said that their institution started implementing the procedure after a 2005 reported that patients on angiotensin II inhibitors, heparin, or calcium-channel blockers were more likely to have vasoplegic syndrome.(1) Once the team instituted the procedure, he said, "we found we were no longer giving phenylephrine [to patients] on bypass."

To evaluate the effects of methylene blue the researchers conducted a chart review of nursing records, anaesthesia records, and perfusion pump records of 260 patients undergoing CABG with bypass pump during the surgery, who received intravenous methylene blue 2 mg/kg during induction before sternal opening. The researchers assessed haemodynamics indices, patients' fluid requirements, and inotropic requirements, ventilator times, and length of stay in surgical intensive care unit in a series.

They compared the treatment cohort to a historical control group of 130 patients who had bypass without methylene blue.

Results revealed that 75% of the group receiving the dye did not require an inotrope, compared with 29% of those that did not receive the dye (P < .0001).

No adverse events were evident for methylene blue.

"There's an obvious benefit to the patient without any adverse side effects," the researchers concluded. "We propose routine use of [methylene blue] prior to all [cardiopulmonary bypass] procedures."

A prospective, randomised trial would establish the treatment as the standard of care, the investigators concluded.

1. Ozal E et al. Ann Thorac Surg. 2005;79:1615-1619.

[Presentation title: Prophylactic Use of Methylene Blue Prevents Vasoplegic Syndrome After Coronary Artery Bypass Graft.]

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