Airway · 8 min
Airway — last-night quick guide
Default plan, predictors, equipment, induction, failure ladder.
Rule
Default plan
Pre-oxygenate (FiO2 1.0 × 3 min or 8 vital-capacity breaths) → induction → laryngoscopy → ETT → confirm ETCO2. Plan B before you start: bougie, video laryngoscope, LMA, surgical airway.
Difficult airway predictors
- LEMON (look, evaluate 3-3-2, Mallampati III/IV, obstruction, neck mobility)
- MOANS — difficult mask (mask seal, obese, age, no teeth, stiff lungs)
- RODS — difficult LMA (restricted mouth, obstruction, distorted, stiff lungs)
- SHORT — difficult cric (surgery, hematoma, obese, radiation, tumor)
Mnemonic — LEMON
LEMON — Difficult airway prediction
LEMON details
- LLook externally — facial trauma, beard, large incisors, large tongue, short neck
- EEvaluate 3-3-2 — 3 finger mouth opening, 3 finger mentum-to-hyoid, 2 finger hyoid-to-thyroid
- MMallampati class — III/IV correlates with difficulty
- OObstruction — stridor, FB, abscess, tumor, hematoma
- NNeck mobility — flexion/extension limits (RA, AS, halo, cervical fusion)
Failing 2+ predicts difficult laryngoscopy. Add MOANS for difficult mask + RODS for difficult LMA + SHORT for difficult cric.
Mnemonic — SOAP-ME
SOAP-ME — Airway preparation checklist
SOAP-ME prep checklist
- SSuction (working, Yankauer + soft, on)
- OOxygen (delivery system + backup tank, capnography active)
- AAirway equipment (mask, OPA, NPA, LMA, ETT in 2 sizes, stylet, bougie, video laryngoscope)
- PPharmacology drawn (induction, paralytic, pressors, atropine, naloxone, sugammadex)
- MMonitors (5-lead ECG, NIBP cuff, SpO₂, capnography, temp, NMB monitor for paralytic cases)
- EEquipment (functional anesthesia machine, IV access verified, tilt table function, defibrillator nearby)
Run through SOAP-ME aloud as part of your time-out. Especially critical for difficult airway cases.
ETT sizing — adults
| Patient | Cuffed ID |
|---|---|
| Adult male | 8.0–8.5 |
| Adult female | 7.0–7.5 |
| Adult depth at lip | 21–23 cm |
ETT sizing — peds
| Age | Cuffed ID | Depth |
|---|---|---|
| Term neonate | 3.0 | 9–10 cm |
| 6 mo | 3.5 | 10–11 cm |
| 1 yr | 4.0 | 11 cm |
| >2 yr cuffed | (age/4)+3.5 | (age/2)+12 |
Rule
Failed intubation ladder
(1) Optimize: head position, BURP, blade size. (2) Adjuncts: bougie, VL. (3) Supraglottic rescue (LMA). (4) Wake up if elective. (5) Cricothyrotomy if can't intubate, can't oxygenate.
Watch out
Awake intubation
If predicted difficult AND poor mask seal AND poor SGA option → awake fiberoptic. Glycopyrrolate 0.2-0.4 mg IV + lidocaine 4% nebulized + topical 4% spray + transtracheal lidocaine 4 mL. Sedation light: dex + low-dose midaz.