The pharmacokinetics of cisatracurium in patients with acute respiratory distress syndrome

Continuous neuromuscular blockade is often necessary in patients being trea ted for acute respiratory distress syndrome (ARDS) to optimize oxygenation. In this study, neuromuscular blockade (no response to two responses at the train-of-four stimulation at the orbicularis oculi muscle) was achieved in six patients with ARDS by a continuous infusion of cisatracurium. The plas ma concentration of cisatracurium during the infusion averaged 1.00 (0.25-1 .45) mug/mL, expressed as median (range). The clearance and half-life were 6.5 (3.3-7.6) mL . min(-1) . kg(-1) and 25 (16-48) min, respectively. The l audanosine plasma concentrations were 0.70 (0.12-1.20) mug/mL. The pharmaco kinetic variables of cisatracurium are similar to those of patients without organ failure undergoing elective surgery. Plasma laudanosine levels alway s remained well less that those associated with seizure activity in animal models. Long-term infusion of cisatracurium was not associated with any sid e effects. Cisatracurium is a suitable muscle relaxant when deep and contin uous levels of muscle relaxation are required in patients treated for ARDS.