What is the best bag mask (bag-valve-mask) technique?

Best Bag-Mask Ventilation Technique

The most effective bag-mask ventilation technique is the two-person method, where one rescuer uses both hands to maintain a tight seal between the mask and face while the second rescuer squeezes the bag to deliver ventilation. 1

Key Components of Effective Bag-Mask Ventilation

Equipment Selection

• Use an adult (1-2 L) bag for adult patients 1
• Deliver approximately 600 mL tidal volume for adults 1
• Use a self-inflating bag with volume of at least 450-500 mL for infants and children 1
• Select a transparent mask to allow detection of regurgitation 1
• Ensure the bag-mask device has:
  • Non-jam inlet valve
  • Standard 15-mm/22-mm fittings
  • Oxygen reservoir capability
  • Non-rebreathing outlet valve 1

Proper Technique

Two-Person Technique (Preferred)

1. First rescuer: Uses both hands to open airway and maintain tight mask-to-face seal
2. Second rescuer: Squeezes the bag until chest visibly rises
3. Both rescuers: Watch for chest rise to confirm effective ventilation 1

Single-Person Technique (When Two-Person Not Available)

• For novice providers, the E-O technique is superior to the conventional E-C technique 2
  • E-O technique: Encircle mask neck with web between thumb and index finger while other digits provide chin lift
  • E-C technique: Index fingers and thumbs form two "C"s while remaining fingers lift mandible forming two "E"s

Advanced Techniques

• Recent research shows the "hook technique" may provide higher success rates (93.3%) compared to traditional E-C (89.6%) and Thenar Eminence (87.2%) techniques 3
• For patients with suspected cervical injury, jaw thrust maneuver produces comparable tidal volumes to two-handed E-C technique with head fully extended 4

Ventilation Parameters

• Deliver each breath over approximately 1 second 1
• Watch for visible chest rise (primary indicator of effective ventilation) 1
• For adults with spontaneous circulation requiring ventilatory support:
  • Provide 1 breath every 5-6 seconds (10-12 breaths/minute) 1
• During CPR without advanced airway:
  • Deliver cycles of 30 compressions and 2 breaths 1

Common Pitfalls and How to Avoid Them

Excessive Ventilation

• Healthcare providers often deliver excessive ventilation during CPR 1, 5
• Avoid excessive ventilation as it:
  • Increases intrathoracic pressure
  • Impedes venous return
  • Decreases cardiac output, cerebral blood flow, and coronary perfusion
  • Causes air trapping and barotrauma in patients with small-airway obstruction
  • Increases risk of regurgitation and aspiration 1, 5

Poor Mask Seal

• Inadequate seal is a common cause of ineffective ventilation
• If chest does not rise:
  1. Reopen the airway
  2. Verify tight seal between mask and face
  3. Reattempt ventilation 1

Special Considerations

• For patients with airway obstruction or poor lung compliance:
  • Higher inspiratory pressures may be needed
  • Ensure bag-mask device allows bypassing pressure-relief valve if necessary 1
• Use supplementary oxygen (concentration >40%, flow rate 10-12 L/min minimum) when available 1
• For lone rescuers during CPR, mouth-to-barrier device techniques are preferred over bag-mask ventilation due to complexity 1

By following these guidelines and practicing these techniques regularly, healthcare providers can optimize bag-mask ventilation to improve patient outcomes during respiratory emergencies.