Underscoring the frequency and prominence of BVM use in the United States, the American Heart Association (AHA) Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiac Care recommend that "all healthcare providers should be familiar with the use of the bag-mask device.

Two principal types of manual resuscitators exist; one version is self-filling with air, although additional oxygen (O2) can be added but is not necessary for the device to function.

The other principal type of manual resuscitator (flow-inflation) is heavily used in non-emergency applications in the operating room to ventilate patients during anesthesia induction and recovery.

The bag valve mask concept was developed in 1956 by the German engineer Holger Hesse and his partner, Danish anaesthetist Henning Ruben, following their initial work on a suction pump.

[citation needed] The BVM consists of a flexible air chamber (the "bag", roughly 30 cm in length), attached to a face mask via a shutter valve.

In order to be effective, a bag valve mask must deliver between 500 and 600 milliliters of air to a normal male adult patient's lungs, but if supplemental oxygen is provided 400 ml may still be adequate.

"[11] Gastric inflation can lead to vomiting and subsequent aspiration of stomach contents into the lungs, which has been cited as a major hazard of bag-valve-mask ventilation,[12] with one study suggesting this effect is difficult to avoid even for the most skilled and experienced users, stating "When using a self-inflatable bag, even experienced anesthesiologists in our study may have performed ventilation with too short inspiratory times or too large tidal volumes, which resulted in stomach inflation in some cases.

"[11] The study goes on to state that "Stomach inflation is a complex problem that may cause regurgitation, [gastric acid] aspiration, and, possibly, death."

In one case of failed resuscitation (leading to death), gastric insufflation in a 3-month-old boy put sufficient pressure against the lungs that "precluded effective ventilation".

Sponge-like lung tissue is delicate, and over-stretching can lead to acute respiratory distress syndrome – a condition that requires prolonged mechanical ventilator support in the ICU and is associated with poor survival (e.g., 50%), and significantly increased care costs of up to $30,000 per day.

[18] Two factors appear to make the public particularly at risk from complications from manual resuscitators: (1) their prevalence of use (leading to high probability of exposure), and (2) apparent inability for providers to protect patients from uncontrolled, inadvertent, forced over-inflation.

Manual resuscitators have no built-in tidal volume control — the amount of air used to force-inflate the lungs during each breath depends entirely on how much the operator squeezes the bag.

"[21] A separate assessment of another high-skilled group with frequent emergency use of manual resuscitators (ambulance paramedics) found that "Despite seemingly adequate training, EMS personnel consistently hyperventilated patients during out-of-hospital CPR", with the same research group concluding that "Unrecognized and inadvertent hyperventilation may be contributing to the currently dismal survival rates from cardiac arrest.

"[22] A further examination has recently been made to assess whether a solution to the over-ventilation problem may lie with the use of pediatric-sized manual resuscitators in adults or use of more advanced flow-inflation (or "Mapleson C") versions of manual resuscitators: while "the paediatric self-inflating bag delivered the most guideline-consistent ventilation", it did not lead to full guideline compliance as "participants hyperventilated patients' lungs in simulated cardiac arrest with all three devices.

With use of manual resuscitators, neither rate nor inflating volumes can be physically controlled through built-in safety adjustments within the device, and as highlighted above, studies show providers frequently exceed designated safety guidelines for both ventilation rate (10 breaths per minute) and volume (5–7 mL/kg body weight) as outlined by the American Heart Association[1] and European Resuscitation Council.

[25] This study found that excessive rate more than triple the current guideline (e.g., 33 breaths per minute) may not interfere with CPR when inspiratory volumes are delivered within guideline-compliant levels, suggesting that ability to keep breath sizes within guideline limits may individually mitigate clinical dangers of excessive rate.

[25] A recent advancement in the safety of manual ventilation may be the growing use of time-assist devices that emit an audible or visual metronome tone or flashing light at the proper guideline-designated rate interval for breath frequency; one study found these devices may lead to near 100% guideline compliance for ventilation rate.

the only devices that can deliver pre-set, physician-prescribed inflation volumes reliably within safety guidelines are mechanical ventilators that require an electrical power source or a source of compressed oxygen, a higher level of training to operate, and typically cost hundreds to thousands of dollars more than a disposable manual resuscitator.

A covered port may be incorporated into the valve assembly to allow inhalatory medicines to be injected into the airflow, which may be particularly effective in treating patients in respiratory arrest from severe asthma.