[Trial of a new technic of transcutaneous diaphragmatic electrostimulation in man]

A new method of diaphragmatic pacing by transcutaneous electrical stimulation, using alternative currents with frequency and amplitude modulations, was tested in 12 subjects: 3 were normal and awake (group I); 4 were studied in acute respiratory failure while under mechanical ventilation and central apnea (group II) and 5 were studied while anaesthetized for peripheral venous surgery and breathing spontaneously (group III). Stimulation was performed either during spontaneous ventilation (groups I and II) or during short periods of respiratory depression (group III). Tidal volume was measured by pneumotachography. A positive correlation was found between stimulus intensity and inspired volume. This effect was not due to voluntary control alone, since diaphragmatic stimulation could support 24% of the theoretical minute ventilation in group II subjects and 64% in group III subjects. These preliminary results demonstrate the relative efficacy of this new method of diaphragmatic pacing using computerized alternative currents.