Bag-Valve-Mask Ventilation: One- and Two-Rescuer Techniques

Why Bag-Valve-Mask Ventilation Matters

Bag-valve-mask (BVM) ventilation is one of the most critical skills in emergency medical services. When a patient cannot breathe adequately on their own, you become their respiratory system. Done correctly, BVM ventilation delivers oxygen-rich air into the lungs and supports life until more definitive airway management is available. Done incorrectly, it can cause gastric distension, aspiration, and inadequate oxygenation — any of which can seriously harm or kill a patient.

Mastery of BVM technique is required at both the EMT and Paramedic level and is tested on NREMT practical and cognitive examinations.

Equipment Overview

A BVM unit has three main components: a self-inflating bag, a one-way valve, and a face mask. Most adult BVMs hold approximately 1,500 mL of air; the bag should never be fully compressed for routine ventilation. Pediatric and infant BVMs are smaller and sized to match the patient. When connected to supplemental oxygen, a BVM should deliver a high fraction of inspired oxygen. A reservoir attached to the bag further increases delivered oxygen concentration.

Always select the correct mask size. The mask should cover the patient's mouth and nose completely, from the bridge of the nose to the cleft of the chin, without covering the eyes or overlapping the chin excessively.

One-Rescuer BVM Technique

One-rescuer BVM ventilation is challenging because a single provider must simultaneously maintain a mask seal and squeeze the bag. The technique most widely taught and validated is the EC-clamp:

• Place the mask over the patient's face with the apex (narrow end) over the bridge of the nose.
• Use your non-dominant hand: form a "C" with your thumb and index finger pressing down on the top of the mask; curl your remaining three fingers (forming an "E") under the patient's mandible (jaw) to perform a jaw thrust or jaw lift.
• Pull the jaw up into the mask rather than pushing the mask down onto the face. This keeps the airway open and creates a better seal.
• With your dominant hand, squeeze the bag smoothly.

For an adult patient, deliver each breath over approximately 1 second, aiming for visible chest rise only — not maximal bag compression. Current EMS guidelines call for a ventilation rate of 10–12 breaths per minute for adults without an advanced airway in place. Squeeze gently enough to produce a visible chest rise. Over-ventilation is dangerous: it causes gastric distension, increases aspiration risk, and in cardiac arrest can impair venous return.

For pediatric and infant patients, use the appropriately sized mask and BVM. The ventilation rate is higher — follow current guidelines for the patient's age group (rates are generally faster for infants and children than for adults). The tidal volume cue remains the same: deliver only enough to produce visible chest rise. Infant lungs are small; a gentle squeeze is all that is needed. Never use an adult BVM on an infant.

Two-Rescuer BVM Technique

Two-rescuer BVM ventilation is more effective and is the preferred method whenever a second provider is available. Roles are divided:

• Mask holder: Uses both hands on the mask — thumbs and index fingers form two "C" shapes pressing down, while the remaining fingers lift the jaw on both sides. This bilateral technique produces a dramatically better mask seal than one-handed grip.
• Bag squeezer: Uses both hands to squeeze the bag smoothly and deliver the breath on the mask holder's cue.

Communication between partners is essential. The mask holder watches for chest rise and signals or calls out each breath. Partners should periodically rotate roles to reduce fatigue. During the two-rescuer drill, you will also practice suction readiness: if the patient vomits, immediately turn them to the lateral (recovery) position, suction the oropharynx with a rigid (Yankauer) suction catheter, then reposition and resume ventilation. Delay in suctioning risks aspiration.

Avoiding Hyperventilation

Hyperventilation — ventilating too fast or with too much volume — is one of the most common BVM errors in the field and in simulations. In cardiac arrest patients, excessive ventilation raises intrathoracic pressure, reduces cardiac output, and worsens outcomes. Use a watch or have your partner count to maintain the correct rate. Let the chest fully fall between breaths before delivering the next ventilation.

Safety Points

• Confirm chest rise on every breath. No visible rise means no effective ventilation. Reposition the airway, reseat the mask, or consider an obstruction.
• Watch for gastric distension. A visibly distending abdomen means air is entering the stomach, not the lungs. Reduce your tidal volume, improve your mask seal, and reposition the airway.
• Suction is always nearby. Have suction on and ready before you begin BVM ventilation. Vomiting can occur without warning.
• Size equipment to the patient. Using an adult mask on an infant or an adult BVM on a child risks delivering dangerous volumes.
• Maintain infection control. Use gloves and a mask/eye protection during BVM ventilation.