Methylene blue increases myocardial function in septic shock

OBJECTIVETo study whether the circulatory changes of human septic shock are mediated in part by nitric oxide. DESIGNOpen-label, nonrandomized clinical trial on the effects of methylene blue, an inhibitor of nitric oxide action. SETTINGIntensive care unit of a teaching hospital. PATIENTSNine consecutive patients with documented septic shock and a pulmonary artery catheter in place, after initial resuscitation with fluids, sympathomimetics, and mechanical ventilation. INTERVENTIONSHemodynamic and metabolic variables were measured before and then 15, 30, 60, and 120 mins after the start of a 20-min infusion of 2 mg/kg of methylene blue. MEASUREMENTS AND MAIN RESULTSPatients had a hyperdynamic circulation, and methylene blue increased (p < .01) mean arterial pressure from 84 +/- 18 to 109 +/- 31 mm Hg and cardiac index from 4.7 +/- 0.9 to 5.6 +/- 1.2 L/min/m, before and 30 mins after starting the methylene blue infusion, respectively. Cardiac filling pressures did not change. In the same time interval, the subnormal systemic vascular resistance index increased (p = .09) and arterial compliance decreased (p < .05). Oxygen delivery and oxygen uptake increased (p