The use of methylene blue in abdominal aortic surgery: a case report.

The open abdominal aortic surgery includes a well-known phase in which arterial blood flow is stopped by occluding clamps, resulting in peculiar physiologic changes usually superimposed on advanced pathologic conditions. An anesthetic plan should aim at providing hemodynamic stability and preserving organ function. Clamp removal leads to an acute fall in blood pressure following a decrease in systemic vascular resistance, caused by reactive hyperemia due to opening of the previously minimally perfused vascular beds. Several different mediators, including the nitrous oxide (NO) pathway, have been thought to be responsible for this hemodynamic effect. The massive production of NO by the inducible isoform of NO synthase could be partially responsible for the profound vasodilatation and myocardial dysfunction. The dye methylene blue (MB) has been used as to prevent vasodilatation in other clinical situations like sepsis, cardiopulmonary bypass and liver transplantation. We describe its use in a patient with poor hemodynamic status, who was submitted to aortic aneurism repair with infrarenal cross clamp. The intervention was also associated with a severe bleeding. In this case MB allowed us to control hypotension with relatively low doses of vasopressors.