Does methylene blue administration to septic shock patients affect vascular permeability and blood volume?

Abstract: Objective: To assess the effects of the inhibition of guanylate cyclase, an enzyme involved in sepsis-related vascular and myocardial dysfunctions, on hemodynamic variables including blood volume and pulmonary vascular permeability during septic shock. Design: Prospective, open study with repeated measurements. Setting: A medicosurgical intensive care unit of a university hospital. Patients: Fifteen patients with septic shock associated with persisting hypotension despite conventional treatment including fluid loading, vasopressors, and inotropes. Interventions: A fiberoptic catheter was inserted for the determination of blood and extravascular volumes by the thermal-dye double indicator technique, using indocyanine green (COLD system). A bolus dose of methylene blue (3 mg/kg) was infused intravenously over 10 mins. COLD-derived variables were recorded before methylene blue and 20 mins, 1 hr, and 2 hrs after the end of methylene blue infusion. Measurements a...