Difficult Airway Algorithms

Difficult Airway: Predict & Prep - Trouble Spotting 101

• Predictors (📌 Mnemonics):
  • LEMON: Look, Evaluate 3-3-2, Mallampati, Obstruction, Neck mobility.
  • MOANS: Mask seal, Obesity/Obstruction, Age >55, No teeth, Stiff lungs/Sleep apnea (difficult BMV).
  • RODS: Restricted mouth, Obstruction, Distorted airway, Stiff lungs/C-spine (difficult EGD).
  • SHORT: Surgery, Hypoxemia, Obstruction, Radiation, Tumor (difficult cricothyrotomy).
• Assessment:
  • Mallampati Score (I-IV).

    ⭐ Mallampati Class III & IV strongly predict difficult intubation.

  • Thyromental Distance (TMD): < 6 cm (< 3 FBs).
  • Inter-Incisor Gap (IIG): < 3 cm (< 2 FBs).
  • Upper Lip Bite Test (ULBT): Class I-III.
  • Neck: ↓ mobility, short/thick.
• Prep:
  • Anticipate & get help.
  • Equipment ready (laryngoscopes, ETTs, SGA, VL, cric kit).

ASA Airway Algorithm - Charting the Course

• Goal: Maintain oxygenation. Follow Plan A, B, C, D.
• Key Decision Point 1: Awake Intubation vs. Intubation after GA.
  • Consider Awake Intubation if: high aspiration risk, anticipated very difficult airway, patient cooperation possible.
• If Intubation After GA Induction:
  • Attempt laryngoscopy & intubation (max 3 attempts).
  • If intubation fails: Assess ventilation.
    • CAN VENTILATE (Face Mask / LMA): Call for help. Pursue alternative strategies (e.g., LMA, video laryngoscopy, fiberoptic intubation via LMA). Consider awakening patient.
    • CANNOT INTUBATE, CANNOT VENTILATE (CICV): Declare emergency! Call for help.
• CICV Emergency Pathway:
  • Attempt LMA as rescue if not already definitive.
  • If LMA fails or not feasible: Proceed to Emergency Invasive Airway (e.g., cricothyroidotomy).

⭐ Throughout any difficult airway scenario, continuous administration of 100% oxygen is paramount, unless contraindicated.

Advanced Moves & CICO - Airway Rescue Ops

• Advanced Adjuncts:
  • Videolaryngoscopy (VL): Improves glottic view (e.g., C-MAC, GlideScope).
  • Intubating LMA (ILMA): For blind or FOB-guided intubation.
  • Flexible Bronchoscopy (FOB): Awake intubation standard; also for asleep difficult airways.
• CICO: "Can't Intubate, Can't Oxygenate"
  • Declare CICO, Call for Help!
  • Prioritize Oxygenation.
  • Front-of-Neck Access (FONA) is life-saving.

-   **Surgical Cricothyroidotomy:** Scalpel-bougie-tube technique. Faster, higher success.
    +   📌 Mnemonic: **S**calpel, **F**inger/Forceps, **B**ougie, **T**ube.
-   **Needle Cricothyroidotomy:** **14-16G** cannula + TTJV. Risk: barotrauma, CO₂ retention.
-   Definitive airway (tracheostomy) follows.

⭐ In CICO, surgical cricothyroidotomy is often preferred over needle cricothyroidotomy for higher success and fewer complications if TTJV expertise is limited.

High‑Yield Points - ⚡ Biggest Takeaways

• The ASA Difficult Airway Algorithm is key for managing challenging airways.
• Predictors: Mallampati Class III/IV, thyromental distance < 6 cm, inter-incisor gap < 3 cm, and limited neck mobility.
• LMA (Laryngeal Mask Airway) is a crucial rescue device, vital in Cannot Intubate, Cannot Ventilate (CICV) scenarios.
• Emergency cricothyroidotomy is the ultimate rescue for a failed airway.
• Awake intubation (e.g., fiberoptic) is preferred for anticipated difficult airways.
• Thorough pre-oxygenation and apneic oxygenation are critical before and during airway management.
• Video laryngoscopy often improves glottic visualization and intubation success rates in difficult airways.