Fig. (3) The Ventrain® device. This simple-to-operate manual ventilator is operated using one’s thumb and index finger. It features active expiration based on the Bernoulli Principle, allowing ventilation through small-bore tubes. In addition to inspiratory (flow directed to patient) and expiratory (flow directed from patient) modes of operation, an equilibration (safety) mode is available where no significant pressure is present at the tip of the attached ventilation catheter.