Although the terms are often used interchangeably when talking about the medical device that makes it easier for patients to breathe, ventilators and respirators are two different things. According to the American Thoracic Society, mechanical ventilators are devices that deliver air into the lungs through a tube placed within the windpipe. A respirator, on the other hand, refers to a mask that filters harmful substances from the air.
Medical ventilators help patients who aren't able to breathe on their own by delivering oxygen to the lungs, carrying away carbon dioxide and lowering the effort required to breathe. These machines are most often used in instances of respiratory failure or when trauma makes it impossible for air to pass through the trachea. In addition to a ventilator, the machine is often referred to as a breathing machine or respirator by medical professionals and lay persons alike.
Respirators are most often used in work settings such as construction sites, mines and other sites including those where fires that release harmful toxins may be present. Also called personal protection equipment or PPE, a respirator is a self-contained device that covers the nose and mouth. Some devices may even cover the eyes or entire face.