Abstract: A medical ventilator comprises a ventilator duct having an inlet for respiratory fresh gas. The pressure at which the respiratory fresh gas is supplied to the patient is determined by a driving jet disposed in the ventilator duct at a distance from the inlet so that an intervening column of gas acts as a pneumatic piston. The supply of driving gas to the jet is initially set by a regulator to obtain a desired value of a respiratory parameter, such as the volume of gas ventilating the patient's lungs during the breathing cycle. The volume of gas expelled from the patient's lungs is monitored during operation by detecting means and the regulator is adjusted by a servomotor in response to any change in the measured parameter in order to maintain the parameter at the desired value.

Abstract: An oscillatory medical ventilator comprises a ventilator duct having one end for attachment to the a patient tube. A gas supply jet is mounted in a bearing block for rotation by an electric motor. The jet has a gas supply passage to which driving or respiratory gas is supplied continuously during rotation of the jet by a gas supply chamber encircling a shaft of the jet and communicating with the passage through radially extending openings in the wall of the shaft. A cyclically varying pressure at one end of the ventilator duct is thus produced upon rotation of the jet to cause alternating inflation and deflation of the lungs with respiratory gas which is supplied either by the jet or an independent source connected to the patient tube.

Abstract: A respirator for use in replacing or assisting the respiratory function in patients in whom spontaneous respiration is either absent or insufficient is described. The respirator includes a respirator conduit having a down-stream end which is attachable to a proximal end of a patient tube 3. A respiratory gas line 6 is connected to a downstream section of the conduit and opens into the conduit at a first location adjacent but upstream of the downstream end 4. An axially extending driving gas jet nozzle 11 is provided at a location which is at least one tidal volume upstream from the patient attachment 4, where the respiratory fresh gas is supplied. The driving gas from the driving jet 11 simply controls the tidal volume like a pneumatic piston and drives the respiratory gas accumulated in the conduit 5 from the supply of the continuous flow of the respiratory gas. The driving gas from jet 11 does not take part in the pulmonary gas exchange.

Abstract: A respirator for use in replacing or assisting the respiratory function in patients in whom spontaneous respiration is either absent or insufficient is described. The respirator includes a respirator conduit having a downstream end which is attachable to a proximal end of a patient tube. A respiratory gas line is connected to a downstream section of the conduit and opens into the conduit at a first location adjacent but upstream of the downstream end. An axially extending driving gas nozzle is provided to direct pulses of driving gas toward the downstream end from a second location upstream of the first location.