The Accelograph: a new neuromuscular transmission monitor

A new neuromuscular transmission monitor based on measurement of acceleration is presented. The monitor consists of an acceleration transducer, i.e. a piezo-electric ceramic wafer with an electrode on each side, and a stimulation and computing unit. The transducer can be fastened to the thumb, and when the finger is moved in response to nerve stimulation a voltage difference develops between the two electrodes. The voltage is then measured and registered in the computing unit. The acceleration transducer does not require preload, but merely that the muscle on which the measurement is being made can move freely. The accelograph is therefore easy to set up and operate. In daily clinical practice it has proved possible, using this new apparatus, to achieve reliable evaluation of the degree of non-depolarizing neuromuscular blockade in less than 2 min.