Effect of methylene blue on oxygen metabolism in patients with septic shock / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of methylene blue (MB) on oxygen metabolism in patients with septic shock. MethodsForty ASA Ⅱ or Ⅲ patients with septic shock aged 38-64 yr weighing 48-75 kg undergoing emergency surgery were randomly divided into 2 groups ( n = 20 each) group Ⅰ norepinephrine (group NE) and group Ⅱ MB. The patients were unpremedicated. Anesthesia was induced with midazolam, etomidate,sufentanil and vecuronium and maintained with inhalation of 0.5％-1.5％ sevoflurane and intermittent iv boluses of sufentanil and vecuronium. The patients were mechanically ventilated after tracheal intubation. PETCO2 was maintained at 35-45 mm Hg. During operation MB was infused at 0.5-1.0 mg·kg-1·h-1 in group MB and NE at 0.5-2.0 μg· kg-1 · min-1 in group NE respectively to maintain hemodynamic stability. Radial artery was cannulated and connected with Vigileo cardiac output monitor. Right internal jugular vein was cannulated for CVP monitoring.HR, SvO2, MAP, CVP, SV and CI were continuously monitored. Arterial and central venous blood samples were collected simultaneously before induction of anesthesia (T0, baseline), immediately before (T1) and at 30, 60 and 90 min after skin incision (T2-4) and at the end of operation (T5) . Blood gas analysis was performed. O2 consumption index (VO2I), O2 delivery index (DO2I) and O2 extraction rate (ERO2) were calculated. Blood lactate concentration was measured. Results MAP, HR, CVP, SVRI, DO2I, VO2I and ERO2 were significantly higher,while CI and blood lactate concentration lower during operation (T2-5) in group MB than in group NE. MAP, HR,CVP, SVRI, VO2I, DO2I, and ERO2 were significantly higher, while CI and blood lactate concentration were lower during operation (T2-5) as compared with the baseline values at T0 in group MB. In group NE there were no significant change in MAP, HR, CVP and DO2I during operation (T2-5 ) as compared with the baseline at T0. ConclusionIntravenous infusion of MB at 0.5-1.0 mg·kg-1·h-1 during operation may improve hemodynamics and oxygen metabolism in patients with septic shock.