page_title: Bag valve mask
section_title: Method of operation
hierarchical_section_title: Bag valve mask / Method of operation
context_page_description: A bag valve mask, sometimes known by the proprietary name Ambu bag or generically as a manual resuscitator or "self-inflating bag", is a hand-held device commonly used to provide positive pressure ventilation to patients who are not breathing or not breathing adequately. The device is a required part of resuscitation kits for trained professionals in out-of-hospital settings and is also frequently used in hospitals as part of standard equipment found on a crash cart, in emergency rooms or other critical care settings. Underscoring the frequency and prominence of BVM use in the United States, the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiac Care recommend that "all healthcare providers should be familiar with the use of the bag-mask device." Manual resuscitators are also used within the hospital for temporary ventilation of patients dependent on mechanical ventilators when the mechanical ventilator needs to be examined for possible malfunction or when ventilator-dependent patients are transported within the hospital.
context_section_description: Manual resuscitator cause the gas inside the inflatable bag portion to be force-fed to the patient via a one-way valve when compressed by the rescuer; the gas is then ideally delivered through a mask and into the patient's trachea, bronchus and into the lungs. In order to be effective, a bag valve mask must deliver between 500 and 800 milliliters of air to a normal male adult patient's lungs, but if supplemental oxygen is provided 400 ml may still be adequate. Squeezing the bag once every 5 to 6 seconds for an adult or once every 3 seconds for an infant or child provides an adequate respiratory rate (10–12 respirations per minute in an adult and 20 per minute in a child or infant).
  Professional rescuers are taught to ensure that the mask portion of the BVM is properly sealed around the patient's face (that is, to ensure proper "mask seal"); otherwise, pressure needed to force-inflate the lungs is released to the environment. This is difficult when a single rescuer attempts to maintain a face mask seal with one hand while squeezing the bag with other. Therefore, common protocol uses two rescuers: one rescuer to hold the mask to the patient's face with both hands and focus entirely on maintaining a leak-proof mask seal, while the other rescuer squeezes the bag and focuses on breath (or tidal volume) and timing.
  An endotracheal tube (ET) can be inserted by an advanced practitioner and can substitute for the mask portion of the manual resuscitator. This provides more secure air passage between the resuscitator and the patient, since the ET tube is sealed with an inflatable cuff within the trachea (or windpipe), so any regurgitation is less likely to enter the lungs, and so that forced inflation pressure can only go into the lungs and not inadvertently go to the stomach (see "complications", below). The ET tube also maintains an open and secure airway at all times, even during CPR compressions; as opposed to when a manual resuscitator is used with a mask when a face mask seal can be difficult to maintain during compressions.
caption: Operation of bag valve mask
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