Transesophageal electroventilation. Optimization and improvement.

For electroventilation, short duration pulse trains (0.1 ms) were applied between two axillary pads (transchest) and compared with transesophageal electroventilation where pulses passed between the same pads to an esophageal electrode in apneic, pentobarbitone-anesthetized pigs. Significantly greater tidal volumes were produced by transesophageal electroventilation in comparison with transchest. As measured by maintained tidal volumes, duration of inspiratory air flow, peak flow, percentage hemoglobin oxygen saturation (%SaO2), and end tidal carbon dioxide concentration (ETCO2), the optimal requirements for transesophageal electroventilation were pulse frequency 40 Hz, 0.7 s duration pulses, at 60 to 100 V, pulse width 0.1 ms, with the esophageal electrode proximal to the gastroesophageal junction without producing brachial plexus stimulation. The efficiency of transesophageal electroventilation falls off rapidly following ventricular fibrillation. Thus, the application of this technique would be in respiratory arrest with maintained circulation, eg, in drug-induced respiratory depression, severe smoke inhalation, severe emphysema, high cervical cord lesion, and weaning from prolonged mechanical ventilation.