What Does It Mean to Bag Someone Medically?

“Bagging” someone in a medical context means manually pushing air into their lungs using a handheld device called a bag-valve-mask, or BVM. A provider places a fitted mask over the patient’s nose and mouth, then repeatedly squeezes a self-inflating rubber or silicone bag to deliver breaths. The technique is one of the most common ways to ventilate a person who has stopped breathing or cannot breathe adequately on their own, and it shows up everywhere from ambulances and emergency departments to operating rooms and intensive care units. Simple as it sounds, doing it well turns out to be surprisingly difficult, and the details of how it is performed can meaningfully affect whether a patient survives.

The Device Itself

A bag-valve-mask has three core parts. The bag is the soft, compressible reservoir that holds air or oxygen. The valve is a one-way mechanism that directs gas into the patient on the squeeze and lets exhaled air escape into the room rather than back into the bag. The mask is a clear, cushioned piece shaped to fit tightly over the nose and mouth. Most setups also include an oxygen reservoir bag attached to the back end, which allows the device to deliver close to 100 percent oxygen when connected to a flow source. Without supplemental oxygen, squeezing the bag delivers room air, which is about 21 percent oxygen.

The modern BVM traces back to 1957, when Danish anesthesiologist Henning Ruben created what became known as the “Ambu Bag.” A similar product was soon developed in Norway by Asmund Laerdal, working with American anesthesiologists James Elam and Peter Safar. Before these self-inflating designs caught on, earlier attempts at manual ventilation used bellows-style devices, some dating back to recommendations from the Royal Humane Society for resuscitating drowning victims, but none gained widespread popularity.¹ The self-inflating bag was a genuine leap forward because it re-expands on its own after each squeeze, letting a single provider deliver breath after breath without any complex setup. Today, both reusable and single-use disposable versions exist, and guidelines increasingly favor disposable models to avoid reassembly errors with the one-way valve, which have been linked to serious adverse events when reusable devices are taken apart for sterilization and put back together incorrectly.²

When and Why Providers Bag a Patient

The most common scenario is cardiac arrest. When someone’s heart stops and they stop breathing, bystanders or paramedics perform CPR with chest compressions and pair those compressions with ventilation. Bagging is the standard way emergency medical services deliver those breaths. In a multicenter study of out-of-hospital cardiac arrest, patients who received BVM ventilation alongside other early interventions had significantly higher rates of getting a pulse back before reaching the hospital and higher rates of surviving to hospital discharge compared with patients who did not receive that combination of care.³

Cardiac arrest is not the only situation. Bagging is also used to pre-oxygenate a patient before intubation, the process of threading a breathing tube into the airway. The idea is to flood the lungs with oxygen so that the patient has a safety buffer during the seconds when the provider is placing the tube and no air is flowing. One comparison found that while BVM pre-oxygenation and high-flow nasal cannula pre-oxygenation produced similar average oxygen levels during intubation, the BVM group showed a more pronounced dip in oxygen saturation during the brief period of apnea right before the tube went in.⁴ Another concern is that not all BVM devices deliver the same concentration of oxygen. A laboratory study of several commercially available bags found that some failed to deliver a high enough inspired oxygen fraction for reliable pre-oxygenation in a spontaneously breathing model, meaning the brand and design of the device can matter.⁵

Beyond emergency resuscitation and pre-oxygenation, bagging comes up during patient transport. When a critically ill person on a ventilator needs to be moved from one unit to another, the ventilator is sometimes swapped for a BVM for the trip. This works adequately for oxygenation, but a study of patients being moved after cardiac surgery found that drops in blood pressure occurred more frequently during manual bagging than during transport with a portable mechanical ventilator.⁶

How the Technique Works in Practice

Squeezing a bag sounds straightforward, but two things have to happen at once. One hand holds the mask sealed against the patient’s face while the other squeezes the bag. The standard grip is often called the “E-C” technique: two or three fingers form a “C” shape pressing the mask down while the remaining fingers hook under the jaw in an “E” shape to lift the chin. A poor seal means air leaks out around the edges instead of entering the lungs, and an inadequate jaw lift means the tongue or soft tissue can block the airway.

Head position matters enormously. A study testing different head angles during BVM ventilation on a simulation model found that the air volume delivered per breath roughly tripled when the head was tilted back to about 25 to 30 degrees compared to a near-flat position.⁷ A randomized crossover study comparing airway maneuvers found that the jaw thrust and the two-handed technique with the head fully extended both delivered significantly more air than the same grip with the head in a neutral position.⁸ In plain terms, if the patient’s head is flat and the jaw is not lifted, much of the squeeze goes nowhere useful.

One Person Versus Two

One persistent challenge with bagging is that one person has to simultaneously hold the mask, maintain the jaw lift, and squeeze the bag. When a second provider is available, one person can use both hands to hold the mask and keep the airway open while the other squeezes the bag. Research consistently shows this two-person approach works better.

In a study comparing one-person and two-person BVM technique on infant and child manikins, the two-person method produced higher air volumes per breath across all provider types. Paramedics were the only group who managed to hit recommended volumes with one person; other clinicians fell short unless they had a partner holding the mask.⁹ A trial in premature newborns found that mask leak was significantly higher with one-person ventilation, averaging about 26 percent leak compared to roughly 18 percent with two people.¹⁰ A manikin study of newborn ventilation devices confirmed the same pattern, with two-person ventilation roughly halving the amount of air escaping around the mask compared to one-person technique.¹¹

The practical takeaway is that whenever two trained people are available, guidelines generally recommend the two-person method. In the field, of course, a single paramedic or nurse may be alone with a patient, making the one-person technique a necessary reality.

What Can Go Wrong

Bagging is safer than having no ventilation at all, but it comes with real risks, especially in unskilled hands or high-stress situations.

• Gastric insufflation: If the bag is squeezed too hard or too fast, pressure builds up faster than the lungs can accept it. Excess air gets forced down the esophagus and into the stomach, a problem called gastric insufflation. A distended stomach pushes against the diaphragm, making further ventilation harder, and raises the risk of the patient vomiting and aspirating stomach contents into the lungs.¹² Slower, gentler squeezes reduce the peak pressure and help keep air going to the lungs rather than the stomach.¹³
• Barotrauma: Overly aggressive squeezing can also damage the lungs themselves. Case reports describe patients who developed pneumothorax, a condition where air leaks out of the lung and collapses it, after receiving manually delivered breaths with excessive pressure.¹⁴ One case involved a patient who developed bilateral pneumothorax, air around the heart, and air in the tissue layers of the abdomen, all attributed to inappropriate manual ventilation during a hospital transfer.¹⁵
• Hyperventilation: Providers under stress tend to bag too fast, delivering more breaths per minute than the patient needs. Hyperventilation drops the level of carbon dioxide in the blood, which can reduce blood flow to the brain and, during cardiac arrest, reduce the effectiveness of chest compressions by increasing pressure inside the chest.

These risks are why training emphasizes “low and slow”: squeeze gently, deliver the breath over about one second, and aim for just enough volume to make the chest rise visibly, not a forceful blast.

Airway Adjuncts That Improve Outcomes

Providers often pair the BVM with simple plastic devices inserted into the mouth or nose to help keep the airway open. An oropharyngeal airway is a curved piece of rigid plastic placed over the tongue to prevent it from falling back and blocking the throat. A nasopharyngeal airway is a flexible tube inserted through the nostril into the back of the throat. Neither requires any special equipment or advanced training.

Adding these adjuncts makes a measurable difference. A study of in-hospital cardiac arrest found that patients who received BVM ventilation with an airway adjunct in place had roughly three and a half times the odds of a good neurological outcome compared with BVM ventilation alone.¹⁶ A separate evaluation of jaw-thrust devices found they were more effective at increasing air delivery and reducing airway resistance than either type of airway adjunct alone, suggesting that the jaw-lift maneuver and a plastic airway insert work through complementary mechanisms.¹⁷

Pediatric Bagging Has Its Own Pitfalls

Children and especially infants present unique challenges. Their airways are smaller and more pliable, their lungs hold less volume, and the margin between “enough air” and “too much pressure” shrinks dramatically. Pediatric BVM bags are smaller than adult ones to account for this, and most come equipped with a pressure-relief valve, sometimes called a pop-off valve, designed to vent air if the pressure inside the circuit gets too high.

That safety feature can backfire. In emergency situations, the pop-off valve may vent air that the child actually needs, leading to inadequate ventilation. Emergency airway experts have recommended that pop-off valves be deactivated during resuscitation, but this guidance has not been widely disseminated, and many providers are unaware the valve is even there or what it does.¹⁸ The result is a scenario where a provider squeezes the bag, sees no chest rise, squeezes harder, and the pop-off valve simply releases the extra pressure. Knowing to disable it, or at least recognizing the problem in real time, can be the difference between effective and failed ventilation in a child.

Infection Control During Bagging

Every squeeze of the bag forces air into the patient’s lungs, but exhaled air also leaks out around the mask seal. During infectious disease outbreaks, this aerosolized exhaled air raises concerns for the provider. A study measuring exhaled air dispersion during BVM ventilation found that leak distances averaged around 267 millimeters, roughly the length of a forearm, with the Ambu silicone resuscitator used by nurses. Adding a breathing filter between the bag and the mask significantly reduced the dispersion for most provider groups.¹⁹ The COVID-19 pandemic sharpened this concern considerably, and current guidance in many hospitals now recommends viral filters on all BVM circuits and early intubation when possible to create a closed circuit that minimizes aerosol exposure to staff.

Can Technology Help Providers Bag Better?

One of the persistent problems with bagging is that providers receive almost no feedback in real time. Unlike a mechanical ventilator that displays waveforms and numbers, a BVM gives the provider nothing but the tactile feel of the squeeze and a visual check of chest rise. Given the stress of a resuscitation, most people squeeze too hard and too fast.

Ventilation feedback devices are a relatively new category of technology designed to address this. These are small sensors or displays that clip onto the BVM circuit and show the provider how much air they are delivering per breath and how many breaths per minute they are giving. The evidence so far is encouraging but sobering. In a simulated-arrest manikin study, use of a feedback device jumped the rate of correctly delivered breaths from about 15 percent to roughly 85 to 90 percent.²⁰ In actual field use, however, the improvements have been more modest. One study of paramedics found that guideline-compliant ventilation rates rose only from 1 percent to 3 percent with the feedback device, though the device did reduce excessive tidal volumes and ventilation rates.²¹ A scoping review of feedback devices in out-of-hospital cardiac arrest found that when the feedback specifically targeted insufflation volume, providers brought their ventilation rate and volume closer to guideline targets.²²

The gap between simulation and real-world results is telling. In a calm training room, a screen showing “too much air” prompts an immediate correction. In a chaotic resuscitation with multiple simultaneous tasks, the feedback competes for attention. Even so, the direction of the evidence is clear: providers left to their own judgment during bagging are wildly inconsistent, and anything that nudges them closer to correct technique has value.

Why “Bagging” Remains So Central to Emergency Medicine

Despite all its limitations, the BVM persists because nothing else matches its combination of simplicity, speed, and availability. Advanced airways like endotracheal tubes require specialized skill and a line of sight into the throat. Supraglottic airway devices are faster to place but still involve inserting something into the patient. A BVM requires no insertion, no drugs, and no electricity. It can go from packaging to delivering breaths in seconds, and it works whether you are in a hospital hallway, a parking lot, or a helicopter. That speed matters most in the first minutes of a cardiac arrest or respiratory failure, when delays of even 60 seconds can change outcomes.

The device also serves as a bridge. In many emergencies, bagging is what keeps the patient alive while the team prepares for a more definitive airway. The BVM buys time for medications to be drawn, for equipment to be assembled, and for the most experienced provider in the room to take over. Even in operating rooms with every piece of technology available, anesthesiologists keep a BVM within arm’s reach as a backup in case intubation fails or a ventilator malfunctions. It is, in a real sense, the most important piece of emergency medical equipment that most people outside of healthcare have never heard of.