Fig. (6) (A) The Ventrain^® device shown in a longitudinal section. The device is supplied by an oxygen source connected to the inlet (1). The velocity of the oxygen flow is then accelerated by a jet nozzle (2) and exits via the exhaust pipe (3) creating a negative (subatmospheric) pressure at the side-port (4), which in turn is connected to a catheter in the patient’s airway.