Bag-valve-mask ventilation

What BVM ventilation is (and when you use it)

• Bag-valve-mask (BVM) ventilation = manually delivering breaths via a self-inflating bag connected to a one-way valve and a face mask.
• Main aims: oxygenation (getting O2 into the blood) and ventilation (removing CO2).
• Common uses: pre-oxygenation before intubation, ventilation during induction/apnoea, rescue ventilation in airway obstruction or failed intubation, during CPR.
• It is a core safety skill: if you can ventilate with a mask, you can usually buy time to think and call for help.

Equipment basics (what to check quickly)

• Mask: correct size (covers nose and mouth, sits on bony face, not over eyes), soft cushion intact.
• Bag: adult bag typically 1.5–2 L; ensure it refills easily and valve moves freely.
• Oxygen: connect to wall O2 and turn on; aim for high flow (often 15 L/min) when rescuing or pre-oxygenating.
• Reservoir bag: attach if available for higher delivered oxygen concentration.
• PEEP valve (if available): can help prevent alveolar collapse and improve oxygenation; use cautiously if hypotensive or with significant air trapping.
• Suction: ready and working (Yankauer), especially if secretions/vomit.
• Airway adjuncts: oropharyngeal airway (OPA/Guedel) and nasopharyngeal airway (NPA) available in multiple sizes.

Patient positioning and airway opening

• Position is everything: aim for a ‘sniffing’ position (neck flexion with head extension) in most adults.
• If obese/pregnant: use a ramped position (head and shoulders elevated so the ear canal is level with the sternal notch).
• Airway opening manoeuvres: head tilt–chin lift (if no trauma concern) and jaw thrust (useful if obstruction or reduced tone).
• Suspected cervical spine injury: use jaw thrust with manual in-line stabilisation; avoid excessive head tilt.
• Remove obvious obstruction: dentures may help mask seal; remove loose dentures/foreign bodies; suction secretions.

Getting a good mask seal (the skill that matters most)

• Choose the right mask size: too small leaks; too large sits on soft tissue and leaks.
• Place mask from bridge of nose down to chin; avoid pressing on the eyes.
• One-handed ‘C-E’ grip: thumb and index finger form a ‘C’ on the mask; other fingers lift the mandible (the ‘E’).
• Two-handed technique is often better (especially for new starters): both hands seal and lift jaw while someone else squeezes the bag.
• Aim to lift the jaw into the mask rather than pushing the mask down onto the face (reduces obstruction and leaks).
• If you hear/feel a leak: reposition, adjust head/jaw, consider a different mask size, or switch to two-handed technique.

How to ventilate safely (rate, volume, and pressures)

• Give slow, gentle breaths: aim for visible chest rise, not maximal bag squeeze.
• Typical adult starting point: 10–12 breaths/min (one breath every 5–6 seconds) when not in cardiac arrest.
• During CPR with an advanced airway: 10 breaths/min continuous compressions; without advanced airway follow local BLS/ALS guidance.
• Avoid hyperventilation: too fast/too big increases gastric inflation, regurgitation risk, and can reduce venous return (worsening hypotension).
• If available, use capnography: a consistent waveform suggests effective ventilation and airway patency; falling ETCO2 may indicate low cardiac output, leak, or obstruction.
• If using an anaesthetic circuit (e.g., Mapleson) rather than self-inflating bag, ensure fresh gas flow is adequate and the APL valve is set appropriately.

Airway adjuncts (when and how)

• OPA (Guedel): helps prevent tongue obstruction in an unconscious patient with no gag reflex. Size: corner of mouth to angle of mandible.
• OPA insertion: insert upside down then rotate 180° (classic) or use a tongue depressor to insert without rotation; stop if gagging or laryngospasm risk.
• NPA: useful if limited mouth opening, partial gag reflex, or to improve patency; size roughly nostril to tragus/angle of jaw; lubricate well.
• Avoid NPA if suspected basal skull fracture or significant nasal trauma.
• Adjuncts do not replace positioning and jaw support—use them together.

Troubleshooting: ‘I can’t ventilate’ approach

• Think: Seal, Airway, Breathing, Stomach (leak/obstruction/bronchospasm/gastric inflation).
• Seal: two-handed technique, different mask size, remove beard barrier (use gel/occlusive dressing), check circuit connections.
• Airway: reposition head, jaw thrust, insert OPA/NPA, suction, consider laryngospasm (especially after airway stimulation).
• Breathing: listen for wheeze (bronchospasm), check chest movement symmetry, consider pneumothorax if sudden difficulty and hypotension.
• Stomach: reduce pressure/volume, slow breaths; consider orogastric tube once stable if significant gastric inflation.
• Escalate early: call for senior help; prepare supraglottic airway (e.g., i-gel) if mask ventilation is failing.

Special situations new starters commonly meet

• Obese/OSA: ramped position, two-handed seal, early adjuncts, consider PEEP, be ready to escalate to supraglottic airway.
• Edentulous patient: dentures can improve seal if stable; if removed, consider packing cheeks with gauze to improve fit.
• Beard: expect leak; use two hands, apply gel, or place an occlusive dressing over facial hair to improve seal.
• Vomiting/aspiration risk: suction immediately, head-down/side if feasible, avoid excessive pressures, consider early definitive airway with senior support.
• Children: use appropriately sized bag/mask; gentle breaths; avoid overinflation (higher risk of gastric inflation).