OXYGEN DELIVERY, OXYGEN-CONSUMPTION, AND GASTRIC INTRAMUCOSAL PH ARE NOT IMPROVED BY A COMPUTER-CONTROLLED, CLOSED-LOOP, VECURONIUM INFUSION IN SEVERE SEPSIS AND SEPTIC SHOCK

Objective: To investigate the influence of the neuromuscular blocking agent vecuronium on oxygen delivery (Do(2)), oxygen consumption (Vo(2) ), oxygen extraction ratio, and gastric intramucosal pH in heavily sed ated patients with severe sepsis or septic shock. Design: Prospective, randomized, placebo-controlled, crossover trial, Setting: University hospital intensive care unit. Patients: Eighteen mechanically ventilat ed patients with severe sepsis or septic shock. Interventions: All pat ients were heavily sedated. After baseline measurement, a computer con trolled, closed-loop infusion of either vecuronium or saline was initi ated and further measurements were made at 40 and 60 mins. The procedu re was repeated with the alternative agent after return of neuromuscul ar function. Measurements and Main Results: Do(2), Vo(2), and intramuc osal pH were monitored using pulmonary artery catheters, a gas exchang e monitor, and gastric tonometers. Changes from baseline were compared (paired t-test, p =.05). The vecuronium closed-loop infusion achieved T1 between 5% and 15% at 40 mins. There was a significant difference in the changes from baseline for static respiratory compliance in the vecuronium closed-loop infusion group compared with the saline closed- loop infusion group. There was no significant difference in the change from baseline for systemic or pulmonary vascular resistance, Do(2), V o(2), oxygen extraction ratio, or intramucosal pH. Conclusions: In the se patients, vecuronium infusion achieved the targeted level of paraly sis and improved respiratory compliance but did not alter intramucosal pH, Vo(2), Do(2), or oxygen extraction ratios. With deep sedation, ne uromuscular blockade in severe sepsis/septic shock does not significan tly influence oxygen flux and should be abandoned as a routine method of improving tissue oxygenation in these patients.