Airway Management

Airway Anatomy & Assessment - Know Your Passages!

• Airway Path: Oral/Nasal Cavity → Pharynx → Larynx (Thyroid, Cricoid, Cords) → Trachea.
• Nerves: SLN & RLN (Vagus branches).
• Key Assessments (Predictors of difficult airway):
  • Mouth Opening: < 3 fingers (Inter-incisor gap < 4 cm).
  • Thyromental Distance (TMD): < 3 fingers (< 6.0-6.5 cm).
  • Mallampati: Class III/IV.
  • Neck Mobility: Limited.
  • 📌 LEMON criteria.

⭐ Cricoid: complete ring, narrowest in peds. Glottis: narrowest in adults.

Basic Maneuvers & Adjuncts - Keeping Airways Open!

• Maneuvers (Relieve Obstruction):
  • Head-tilt/Chin-lift: Lifts tongue. ⚠️ Avoid if C-spine injury suspected.
  • Jaw Thrust: Preferred for suspected C-spine injury; displaces mandible anteriorly.
• Adjuncts (Maintain Patency):
  • Oropharyngeal Airway (OPA): Unconscious, no gag reflex. Size: Corner of mouth to angle of mandible.
  • Nasopharyngeal Airway (NPA): Conscious/semiconscious. Size: Tip of nose to earlobe. ⚠️ Basal skull fracture.

⭐ OPA in a patient with an intact gag reflex can induce vomiting or laryngospasm.

Advanced Airway Devices - Securing the Route!

• Supraglottic Airways (SGA): Bridge gap between mask & ETT.
  • LMA: Sizes 3-5 (adults). ProSeal LMA: gastric drain.
  • i-gel: Anatomical seal, no cuff inflation.
  • Laryngeal Tube (LT): Rescue airway.
• Endotracheal Tube (ETT): Definitive airway.
  • Sizes: Adult ♀ 7.0-7.5mm, ♂ 7.5-8.5mm ID.
  • Pediatric (uncuffed): $(Age/4) + 4$.
  • Confirmation: Capnography (gold standard).
• Intubation Aids:
  • Video Laryngoscope (VL): Improves glottic view.
  • Fibreoptic Bronchoscope (FOB): Awake intubation for anticipated difficult airway.

⭐ The LMA Fastrach (Intubating LMA) allows for blind or fibreoptic-guided ETT placement through it.

Difficult Airway Algorithm - Navigating Challenges!

• Anticipate Difficulty: 📌 LEMON criteria:
  • Look externally
  • Evaluate 3-3-2 rule (mouth opening, hyomental distance, thyromental distance)
  • Mallampati score (≥III)
  • Obstruction / Obesity
  • Neck mobility (reduced)
• Primary Goal: Maintain Oxygenation! Call for experienced help early.
• Algorithm Steps (Simplified ASA Guideline):
  • Plan A: Direct Laryngoscopy & Intubation (max 3 attempts by experienced hand).
  • Plan B: Supraglottic Airway Device (SAD/LMA) insertion.
  • Plan C: Facemask Ventilation (FMV). If ventilating, consider awakening or alternative strategy.
  • Plan D: Emergency Invasive Airway (e.g., Cricothyroidotomy) if "Cannot Intubate, Cannot Ventilate" (CICV).

⭐ > In a CICV (Cannot Intubate, Cannot Ventilate) scenario, proceeding to an emergency front-of-neck access (e.g., cricothyroidotomy) is life-saving and should not be delayed.

Rapid Sequence Intubation (RSI) - Swift & Safe Airway!

Goal: Rapid airway control, ↓ aspiration risk. For full stomach, GCS < 8. 📌 7 P's of RSI:

• Induction: Propofol (1.5-2.5 mg/kg), Etomidate (0.3 mg/kg).
• Paralytic: Suxamethonium (1-1.5 mg/kg), Rocuronium (0.6-1.2 mg/kg).
• Avoid Bag-Mask Ventilation (BMV) pre-intubation if possible.

⭐ Succinylcholine, despite rapid onset, is contraindicated in severe burns (>24-48h) and crush injuries due to hyperkalemia risk.

High‑Yield Points - ⚡ Biggest Takeaways

• Mallampati classification (Class III/IV) & thyromental distance <6cm predict difficult laryngoscopy.
• Cormack-Lehane grades 3 & 4 signify poor laryngeal view, indicating difficult intubation.
• Capnography (ETCO2) is the gold standard for confirming endotracheal tube placement.
• Rapid Sequence Intubation (RSI) with cricoid pressure is vital for patients at aspiration risk.
• LMA serves as a primary airway or rescue device in difficult airway algorithms.
• The LEMON criteria (Look, Evaluate, Mallampati, Obstruction, Neck) systematically assess intubation difficulty.