the respirator 31 is released the needle valve 19 and seat 18 assembly allows pressure to be bled off slowly from conduits 36 and 39 and the diaphragm 41 which introduces the element of time to be established for inflation hold in the lungs gas escapes through the needle valve 19 and seat 18 and out the hole 12 so that at some point the gas pressure on the diaphragm 41 is released in operation the respirator 31 cycles into the inspiratory phase as the patient draws gas from the respirator 31 this allows gas to flow under pressure through the respirator 31 from the gas supply 30 inflating the patient 39 s lungs in so doing gas is diverted via conduit 33 to power the nebulizer 38 which breaks up water into minute particles to be carried into the lungs via conduit 37 and breathing element 34 the function of the variable inflation hold control apparatus 10 is introduced at this point in that when a pressure limit has been reached by the respirator 31 in the patient 39 s lungs the respirator 31 pressure cycles off the inflation hold control apparatus 10 retains gas pressure on the diaphragm 41 in the exhalation valve assembly 40 the needle valve 19 in.