A<unk>  is a machine that provides mechanical<unk> ilation by moving breathable air into and out of the lungs, to deliver breaths to a patient who is physically unable to breathe, or breathing insufficiently.<unk> s are computerized microprocessor-controlled machines, but patients can also be<unk> ilated with a simple, hand-operated bag valve mask.<unk> s are chiefly used in intensive-care medicine, home care, and emergency medicine (as standalone units) and in anesthesiology (as a component of an anesthesia machine).<unk> s are sometimes called "respirators", a term commonly used for them in the 1950s (particularly the "Bird respirator"). However, contemporary hospital and medical terminology uses the word "respirator" to refer instead to a face-mask that protects wearers against hazardous airborne substances.
Ventilator
Respirator
Liquid ventilator
Resuscitator
Air purifier
Hypoxicator
Aspirator 
Pneumonic device