Abstract: A manually operated lung-venting apparatus includes a self-expanding bladder having a bladder inlet through which treating gas is drawn into the bladder during expansion thereof and a bladder outlet through which treating gas is driven out of the bladder during compression thereof. The apparatus further comprises a valve device having a housing attached to the bladder; an inlet chamber in the housing; a valve inlet for establishing communication between the bladder and the inlet chamber; a valve outlet which is in continuous communication with the inlet chamber and which is adapted to be connected to the respiratory system of a patient.