1) Breathing apparatus 2) Breathing device 3) Breathing machine 4) Medical equipment 5) Ventilator 
A resuscitator is a device using positive pressure to inflate the lungs of an unconscious person who is not breathing, in order to keep them oxygenated and alive. There are three basic types: a manual version (also known as a bag valve mask) consisting of a mask and a large hand-squeezed plastic bulb using ambient air, or with supplemental oxygen ...
• (n.) One who, or that which, resuscitates.
An obsolete term for an apparatus that forces gas (usually O2) into lungs to produce artificial ventilation. ... (05 Mar 2000) ... 
(re-sus´ĭ-ta″tәr) an apparatus for initiating respiration in persons whose breathing has stopped.
Re·sus'ci·ta`tor noun [ Latin ] One who, or that which, resuscitates. 
[n] - a breathing apparatus used for resuscitation by forcing oxygen into the lungs of a person who has undergone asphyxia or arrest of respiration
resuscitator 1. A breathing apparatus used for resuscitation by forcing oxygen into the lungs of a person who has undergone asphyxia or arrest of respiration. 2. Something that resuscitates, as an apparatus that forces oxygen, or a mixture of oxygen, and carbon dioxide into the lungs of a person who has undergone partial asphyxiation.
noun a breathing apparatus used for resuscitation by forcing oxygen into the lungs of a person who has undergone asphyxia or arrest of respiration