A pocket mask is a small portable device used in the pre-hospital setting to provide adequate ventilation to a patient who is either in respiratory failure or cardiac arrest. The pocket mask is designed to be placed over the face of the patient, thus creating a seal enclosing both the mouth and nose. Air is then administered to the patient by an
emergency responder. The emergency responder exhales through a
one-way filter valve, providing adequate ventilation to the patient. The emergency responder is capable of delivering up to 16% oxygen with his/her breath. Modern pocket masks have either a built-in one-way valve or an attachable, disposable filter to
protect the emergency responder from the patient's potentially infectious bodily substances, such as
vomit or blood. Many masks also have a built-in oxygen intake tube, allowing for the administration of 50-60% oxygen. Without being hooked up to an external line, exhaled air from the provider can still provide sufficient oxygen to live, up to 16%. Earth's
atmosphere consists of approximately 21% oxygen. ==Usage==