Magnetic (eddy-current) electroventilation in the dog.

Abstract

Magnetic (eddy-current) stimulation of the inspiratory motor nerves in the neck of the anesthetized dog was achieved. Using a 10-turn coil wound around the base of the neck and a train of pulses (25/s), inspiration was produced by tetanic contraction of the inspiratory muscles. The volume of air inspired increased with an increase in the voltage applied to the capacitor that was discharged repetitively into the coil. In this 10-dog study, the maximum inspired volume was in excess of the spontaneous tidal volume. In a second study, breathing was captured by repeating the stimulus trains at a rate in excess of the spontaneous breathing rate. Oxygen consumption was measured during spontaneous breathing and with captured breathing. The oxygen uptake with magnetic electroventilation was, on the average, 75% higher than with spontaneous breathing. However body temperature did not increase. Although the neck coil was not critical in placement, its field of stimulation was larger than needed to stimulate the phrenic and accessory motor nerves.