Mask Ventilation

Mask Ventilation Basics - Seal the Deal

• Purpose: Provide temporary oxygenation & ventilation non-invasively; bridge to advanced airway.
• Indications: Apnea, respiratory insufficiency, pre-oxygenation before intubation, procedural sedation.
• Technique - The Seal:
  • Mask Size: Covers mouth & nose; bridge of nose to just above chin (avoiding eye compression).
  • Grip (📌 E-C Clamp):
    • 'C'-shape: Thumb & index finger press mask firmly onto face.
    • 'E'-shape: Remaining 3 fingers lift mandible (jaw thrust), extending atlanto-occipital joint.
  • Two-person technique often superior, especially for difficult seals (e.g., beards, edentulous).
• Goals: Visible chest rise, $SpO_2$ > 90%, presence of end-tidal $CO_2$ (ETCO2).
• Common Problems: Inadequate seal (air leak), airway obstruction (tongue, soft tissues), insufficient tidal volume.

⭐ Inability to maintain oxygen saturation > 90% using a face mask or failure to prevent/reverse signs of inadequate ventilation despite optimal attempts constitutes failed mask ventilation (a component of a difficult airway).

Gear Up - Tools of Trade

• Face Masks:
  • Transparent, anatomical; sizes 0-6. Cushioned rim.
  • Fit: Nasal bridge to mentum; airtight seal.
  • Connector: 22mm female.
• Oropharyngeal Airways (OPA):
  • Types: Guedel, Berman. Color-coded.
  • Action: Lifts tongue off posterior pharynx.
  • Size: Mouth corner to mandible angle.
  • 📌 Guedel: Good airway.
• Nasopharyngeal Airways (NPA):
  • Use: Conscious pt; OPA difficult/trismus.
  • Size: Nares to tragus. Lubricate. Bevel to septum.
  • ⚠️ Avoid: Basal skull fracture, coagulopathy.
• Self-Inflating Bag (Ambu):
  • Positive pressure ventilation. Non-rebreathing valve.
  • FiO2: ~21% (air); up to 100% (O2 + reservoir).

⭐ OPA sizing: Critical. Too large: obstructs larynx/trauma. Too small: ineffective.

Mastering the Mask - Grip & Tricks

• Goal: Effective seal & patent airway for BMV.
• Grips:

  • One-Hand (C-E): Thumb/index ('C') on mask; 3 fingers ('E') lift jaw.

  • Two-Hand (V-E/Thenar Eminence): Both hands on mask, strong jaw thrust. Needs assistant. Best for DMV.

• Key Maneuvers & Adjuncts:
  • Head-tilt/chin-lift (if no C-spine injury).
  • Jaw thrust: Lifts tongue, opens airway.

    ⭐ Jaw thrust is crucial to relieve upper airway obstruction during mask ventilation.

  • OPA/NPA airways: Bypass soft tissue obstruction.
• Troubleshooting & Improving Ventilation:
  • Reposition. Optimize jaw thrust.
  • Use two-person technique.
  • Avoid high pressure (gastric insufflation > 20 cm H₂O).

• DMV Predictors (📌 MOANS):
  • Mask Seal (beard, NGT, anomaly)
  • Obesity (BMI > 30)/Obstruction (OSA)
  • Age (> 55 yrs)
  • No Teeth (edentulous)
  • Stiff Lungs (asthma)/Sleep Apnea

DMV SOS - Spotting Trouble

Difficult Mask Ventilation (DMV) is inadequate alveolar oxygenation using a face mask. Early identification of risk factors is crucial.

📌 BONES Mnemonic for DMV Predictors:

• Beard: Impedes mask seal.
• Obesity: BMI > 30 kg/m².
• No teeth (Edentulous): Poor mask fit.
• Elderly: Age > 55 years (loss of tissue elasticity).
• Snoring/OSA/Stiff Lungs: Indicates potential obstruction or ↑ resistance.

If DMV is suspected or encountered:

⭐ The inability to maintain SpO₂ > 92% with 100% O₂ and optimal technique defines DMV.

High‑Yield Points - ⚡ Biggest Takeaways

• C-E grip is crucial for an effective mask seal.
• Use MOANS mnemonic to predict Difficult Mask Ventilation (DMV).
• Two-person mask ventilation often overcomes DMV challenges.
• OPA/NPA adjuncts help maintain airway patency during mask ventilation.
• Ramping position optimizes airway alignment in obese patients.
• Limit peak inspiratory pressures to <20 cmH2O to prevent gastric insufflation.
• Thorough pre-oxygenation (denitrogenation) is vital before mask ventilation.