Effects of methylene blue on microcirculatory alterations following cardiac surgery: A prospective cohort study

BACKGROUND Methylene blue is used as rescue therapy to treat catecholamine-refractory vasoplegic syndrome after cardiac surgery. However, its microcirculatory effects remain poorly documented. OBJECTIVE We aimed to study microcirculatory abnormalities in refractory vasoplegic syndrome following cardiac surgery with cardiopulmonary bypass and assess the effects of methylene blue. DESIGN A prospective open-label cohort study. SETTING 20-Bed ICU of a tertiary care hospital. PATIENTS 25 Adult patients receiving 1.5 mg kg−1 of methylene blue intravenously for refractory vasoplegic syndrome (defined as norepinephrine requirement more than 0.5 μg kg−1 min−1) to maintain mean arterial pressure (MAP) more than 65 mmHg and cardiac index (CI) more than 2.0 l min−1 m−2. MAIN OUTCOME MEASURES Complete haemodynamic set of measurements at baseline and 1 h after the administration of methylene blue. Sublingual microcirculation was investigated by sidestream dark field imaging to obtain microvascular flow index (MFI), total vessel density, perfused vessel density and heterogeneity index. Microvascular reactivity was assessed by peripheral near-infrared (IR) spectroscopy combined with a vascular occlusion test. We also performed a standardised measurement of capillary refill time. RESULTS Despite normalised CI (2.6 [2.0 to 3.8] l min−1 m−2) and MAP (66 [55 to 76] mmHg), patients with refractory vasoplegic ...
Source: European Journal of Anaesthesiology - Category: Anesthesiology Tags: Cardiac surgery Source Type: research