A simple device for monitoring neuromuscular blockade in children

A simple instrument for measuring adductor pollicis tension in children has been devised. The thumb sensor utilizes a thin conical rubber seal obtained from a 5, 10 or 20 ml Becton Dickinson syringe. A syringe barrel of similar size, fixed at right angles to the sensor, forms a handle for the fist. The sensor is linked to a pressure transducer with non-compliant tubing. Pressure output of the saline-filled system was found to be linearly related to the force exerted on each size of the sensor. In 20 children, aged two to eight years, the device, fitted in turn with the 5, 10 and 20 ml syringe seal sensors, gave train-of-four (TOF) ratios which showed close correlation (coefficient r = 0.96, 0.93, 0.95) and agreement (regression slope b = 0.97, 0.95, 0.98) with those of a force transducer. Thus, inspection of the displayed TOF pressure pulses gives a rapid and reliable estimate of neuromuscular blockade.