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.
