Bag-Valve-Mask (BVM): Definition, Components, and Clinical Use

A bag-valve-mask (BVM) (manual resuscitator, Ambu bag) provides positive-pressure ventilation to apneic or inadequately breathing patients.

Components

• Self-inflating bag (adult: 1.5–2 L; pediatric: 500–750 mL; infant: 250–500 mL)
• One-way valve (prevents rebreathing, directs flow)
• Face mask (cushioned rim, sizes 0–5; clear for monitoring)
• Oxygen reservoir (allows near-100% FiO₂ with O₂ source)
• PEEP valve (optional, for alveolar recruitment)

Technique (Two-Provider Preferred)

1. Position: Head-tilt/chin-lift or jaw-thrust (trauma).
2. Mask seal: "C-E" technique (thumb/index = C on mask; 3 fingers = E on mandible).
3. Squeeze bag over 1 second → visible chest rise.
4. Rate: 10 breaths/min (adult), 20–30 (pediatric/infant).
5. Avoid over-ventilation (increased intrathoracic pressure → decreased venous return).

Indications

• Cardiac/respiratory arrest
• Respiratory failure (pre-intubation, post-extubation)
• Procedural sedation rescue
• Transport ventilation

BVM is a temporizing bridge to definitive airway (ETT, supraglottic). Training and regular practice essential.