Feedback control of neuromuscular blockade. A simple system for infusion of atracurium.

A simple system for closed-loop control of neuromuscular blockade is described. It comprises a Datex Relaxograph, a small relay and a syringe pump. The equipment is commercially available and requires no complex custom-built electronics. Atracurium was infused in a semicontinuous manner to 11 patients who underwent general anaesthesia for a variety of surgical procedures. Neuromuscular blockade oscillated within a narrow range around the preset level. The mean rate of infusion of atracurium was 0.5 mg/kg/hour (SD 0.13). The mean recovery time was 25.5 minutes (SD 7.95).