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I now have enough material from the library plus the blueprint image. Let me compile the comprehensive keyword-based exam answer sheet for all 8 topics.
🧠SECTION 2 — AIRWAY MANAGEMENT: MASTER KEYWORD SHEET
(Exam-ready recall cards — highest yield topics first)
1. 🔴 BRACHIAL PLEXUS — Anatomy, Diagram, 4 Approaches (★★★★★ ×12)
Mnemonic for roots → terminal nerves: "Randy Travis Drinks Cold Beer"
→ Roots → Trunks → Divisions → Cords → Branches
| Layer | Details |
|---|---|
| Roots | C5, C6, C7, C8, T1 |
| Trunks | Upper (C5+C6), Middle (C7), Lower (C8+T1) |
| Divisions | Anterior + Posterior (each trunk splits) |
| Cords | Lateral, Medial, Posterior |
| Terminal branches | Musculocutaneous, Median, Ulnar, Radial, Axillary |
4 Approaches (with key landmarks):
| Approach | Level | Landmark | Best for |
|---|---|---|---|
| Interscalene | Root/Trunk | Between SCM and scalene muscles, C6 level | Shoulder, clavicle surgery |
| Supraclavicular | Trunk/Division | Above clavicle, lat to SCM | Entire upper limb (arm, elbow, forearm) |
| Infraclavicular | Cord | Below clavicle, medial to coracoid | Elbow downwards |
| Axillary | Terminal branches | Axillary artery pulsation | Hand, forearm (safest, no PTX risk) |
Keywords: Interscalene → phrenic nerve block (100%), Horner syndrome, pneumothorax risk · Supraclavicular → "house under the bridge" USG view · Axillary → "BURN" mnemonic (Bicep + Ulnar + Radial + Nerve positions around artery) · LAST = Local Anesthetic Systemic Toxicity (always pair with brachial plexus block) · LAST Rx → Intralipid 20% (1.5 mL/kg bolus) + CPR
USG guidance: identify subclavian artery as circular pulsatile structure; nerves = cluster of grapes appearance
2. 🔴 DIFFICULT AIRWAY — Predictors + AIDAA Algorithm (★★★★★ ×10)
Assessment tools — Know all 3:
LEMON Law
| Letter | Meaning |
|---|---|
| L | Look externally (beard, obesity, receding jaw, large teeth) |
| E | Evaluate 3-3-2 rule (mouth opening 3F, hyoid-chin 3F, thyroid-floor of mouth 2F) |
| M | Mallampati score (I–IV) |
| O | Obstruction (epiglottitis, abscess, tumour) |
| N | Neck mobility (fusion, collar, C-spine injury) |
Mallampati Classification
- Class I: Soft palate, uvula, fauces, pillars visible
- Class II: Soft palate, uvula, fauces visible
- Class III: Soft palate, base of uvula only
- Class IV: Hard palate only visible
- (Class III/IV = predicted difficult laryngoscopy)
Wilson Score — 5 factors (each 0/1/2):
Weight · Head-neck movement · Jaw movement · Receding mandible · Buck teeth
(Score ≥ 2 = difficult intubation)
5 Types of Difficult Airway (Dec 2024 exam):
- Difficult mask ventilation
- Difficult laryngoscopy/intubation
- Difficult SAD placement
- Difficult cricothyroidotomy
- Difficult extubation
AIDAA Algorithm (Indian context):
- A = Awake intubation if predicted difficult
- I = Induction only if adequate personnel/equipment
- D = Device — SAD as rescue
- A = Alert + Awaken if cannot intubate/ventilate
- A = Alternative (surgical airway)
Unanticipated difficult airway plan: Plan A (DL/VL) → Plan B (SAD) → Plan C (2-person mask) → Plan D (CICO → front-of-neck access)
Keywords: Cormack-Lehane grade (I–IV) · video laryngoscopy (VL) as first-line in predicted difficult · Cannot Intubate Cannot Oxygenate (CICO) · extubation of difficult airway = stepwise, consider airway exchange catheter (AEC)
3. 🟠SUPRAGLOTTIC AIRWAY DEVICES (SADs) (★★★★ ×8)
Generation Classification:
| Generation | Features | Examples |
|---|---|---|
| 1st Gen | Ventilation only, no gastric access | Classic LMA, Flexible LMA |
| 2nd Gen | Gastric access port + bite block + improved cuff seal | ProSeal LMA, Supreme LMA, i-gel, AuraGain |
| 3rd Gen | Modifications — intubation channel, better seal | ILMA (Fastrach), AuraGain |
Key Comparisons:
| i-gel | PLMA (ProSeal LMA) |
|---|---|
| Non-inflatable cuff (thermoplastic elastomer) | Inflatable cuff |
| Easier insertion | Better seal pressure (30–40 cmH₂O) |
| Gastric channel | Gastric channel |
| No bite block in original | Bite block present |
AuraGain = 2nd gen + intubation capability (3rd gen hybrid)
3rd Gen modifications: Gastric access · drain tube · bite block · improved cuff seal · intubation capability
Complications of SADs:
- Aspiration (most important)
- Laryngospasm
- Nerve compression (lingual, hypoglossal)
- Epiglottic downfolding
- Airway trauma/sore throat
- Gas leak / inadequate ventilation
Indications/contraindications: CI in non-fasted patients, pharyngeal pathology, airway obstruction below glottis, prone position (relative CI)
Keywords: Seal pressure · drain tube decompresses stomach · rescue device in cannot-intubate · bridge to intubation · ILMA allows blind intubation through device
4. 🟠AWAKE FIBEROPTIC INTUBATION (AFOI) (★★★ ×7)
Indications: Predicted difficult airway · unstable C-spine · severe trismus · large anterior neck mass · patient with full stomach + difficult airway
4 Airway Nerve Blocks:
| Nerve | Supply | Block Technique |
|---|---|---|
| Glossopharyngeal (CN IX) | Posterior 1/3 tongue, oropharynx | Tonsillar pillar injection or nebulization |
| Superior Laryngeal Nerve (SLN) | Sensation above cords (internal br.) | Greater cornu of hyoid injection bilaterally |
| Recurrent Laryngeal Nerve (RLN) | Sensation below cords | Trans-tracheal injection (4% lidocaine, 2–4 mL, at CTM) |
| Transtracheal | Subglottic/tracheal | Through cricothyroid membrane, cough distributes LA |
Topicalization Agents:
- Lidocaine 4% (spray, nebulization, gel)
- Benzocaine 20% spray
- Cocaine 4% (vasoconstriction + analgesia, nasal route)
Sedation for AFOI:
- Dexmedetomidine (alpha-2 agonist) — sedation with maintained airway reflexes; 1 mcg/kg loading over 10 min, then 0.2–0.7 mcg/kg/hr
- Remifentanil TCI — blunts cough reflex, titratable
- Midazolam — antisialogogue + anxiolysis (low dose only)
- Antisialogogue: Glycopyrrolate 0.2 mg IM (dries secretions, improves visibility)
Patient Preparation ("SOAP-M"): Suction · Oxygen · Airway equipment · Personnel · Monitors
Post-AFOI: Check tube position with capnography + FOB confirmation · Extubation plan = stepwise with AEC
5. 🟡 USG IN AIRWAY ASSESSMENT (★★ ×4)
Structures visualized on USG:
| Structure | Appearance |
|---|---|
| Trachea | Air-tissue interface → "comet-tail" artifact, hyperechoic ring |
| Thyroid cartilage | Echogenic structure |
| Cricoid cartilage | Echogenic ring below thyroid |
| Hyoid bone | Hyperechoic with posterior shadow |
| Vocal cords | Seen through thyroid cartilage window |
| Pre-tracheal fat pad | Hypoechoic layer — predicts difficult intubation if thick |
USG for difficult airway prediction:
- Pre-tracheal soft tissue thickness at hyoid > 2.8 cm → predicted difficult
- Tongue base thickness > 6.1 cm → difficult
- Hyomental distance on USG correlates with Mallampati
Tracheal identification: Midline trachea confirms ETT position (rapid confirmation on USG)
- Bilateral lung sliding = correct placement
- Esophageal intubation: tracheal deviation or "double tract" sign
Laryngeal anatomy on USG:
- Epiglottis: hypoechoic inverted V on thyrohyoid window
- Arytenoids: paired echogenic structures
- Subglottic diameter: useful in paediatrics for ETT sizing
Keywords (Dec 2024 explicit): Hyoid · thyroid · cricoid · tongue base · pre-tracheal fat pad · vocal cord visualization
6. 🟡 POST-THYROIDECTOMY AIRWAY + TRACHEOMALACIA (★★★ ×5)
Causes of Post-thyroidectomy Stridor (in order of frequency):
| Cause | Timing | Key features |
|---|---|---|
| Haematoma | Minutes–hours | Most common; wound swelling, tracheal compression |
| Bilateral RLN palsy | Immediate post-op | Both vocal cords adduct (midline) → inspiratory stridor |
| Hypocalcaemia | 24–72 hrs | Tetany, Chvostek/Trousseau signs, laryngospasm |
| Tracheomalacia | Immediate extubation | Softened tracheal rings from long-standing goitre |
Haematoma management: Open wound immediately (bedside), decompress, then re-intubate, then return to OR
Tracheomalacia:
- Cause: Chronically enlarged goitre → external pressure → cartilage softening
- Diagnosis Triad:
- Flow-volume loop: variable intrathoracic obstruction → flattened expiratory limb; extrathoracic → flattened inspiratory limb
- CT neck/chest (dynamic)
- Bronchoscopy (gold standard — direct visualization of collapse)
- Management:
- Conservative: CPAP / NIV
- Reintubation (if collapse at extubation)
- Surgical: tracheal resection, tracheostomy, aortopexy, reimplantation (for extrinsic compression)
Bilateral RLN palsy:
- Both cords paramedian → adducted → airway obstruction
- Acute: reintubation or tracheostomy
- Long-term: arytenoidectomy / vocal cord lateralization
Keywords: Safecracker's sign (stridor + wheezing post-thyroidectomy) · Pemberton's test (facial flushing on arm elevation = thoracic outlet obstruction) · tracheal tug
7. 🟡 LARYNGEAL NERVE SUPPLY + VOCAL CORD PALSY (★★ ×4)
Nerve supply of larynx — both branches of Vagus (CN X):
| Nerve | Branch | Supplies |
|---|---|---|
| Superior Laryngeal Nerve (SLN) | Internal branch | Sensation above vocal cords (supraglottis) |
| External branch | Motor to cricothyroid muscle (pitch/tension) | |
| Recurrent Laryngeal Nerve (RLN) | Left loops around aorta; Right loops around subclavian | ALL intrinsic laryngeal muscles EXCEPT cricothyroid; Sensation below cords |
Memory tip: "SLN = Sensation above + Cricothyroid motor; RLN = ALL the rest"
Vocal Cord Palsy Patterns:
| Type | Cord Position | Symptoms | Emergency? |
|---|---|---|---|
| Unilateral RLN palsy | Paramedian | Hoarseness, weak voice, aspiration | No |
| Bilateral partial RLN palsy | Adductor paralysis (abductors fail) | Inspiratory stridor, respiratory distress | Yes |
| Bilateral complete RLN palsy | Median/paramedian | Inspiratory stridor, acute airway emergency | YES |
| SLN external branch | (cricothyroid weak) | Loss of high-pitched phonation, easy fatigue | No |
Bilateral complete palsy = cords fixed midline → ACUTE AIRWAY EMERGENCY → intubate/tracheostomy
Adductor paralysis = cords can't adduct → hoarseness (commonest presentation of unilateral palsy)
Causes of RLN palsy: Thyroid/parathyroid surgery · thoracic aortic aneurysm · lung/mediastinal malignancy · trauma · idiopathic (viral)
8. 🟡 CRICOTHYROIDOTOMY + PERCUTANEOUS TRACHEOSTOMY (★★ ×4)
Cricothyroidotomy
Indication: CICO — Cannot Intubate Cannot Oxygenate (life-threatening emergency)
Landmark: Cricothyroid membrane (CTM) — between thyroid cartilage (above) and cricoid cartilage (below); soft spot in midline neck
Surgical Cricothyroidotomy steps:
- Extend neck, stabilize larynx (non-dominant hand)
- Vertical skin incision (safer in emergency)
- Horizontal stab incision through CTM
- Insert tracheal hook to stabilise
- Insert size 6.0 cuffed ETT / tracheostomy tube
- Inflate cuff, confirm with capnography
Needle Cricothyroidotomy:
- 14G cannula through CTM
- High-pressure jet ventilation (transtracheal jet ventilation)
- Temporising only — risk of barotrauma, CO₂ retention; max 30–45 min
Percutaneous Dilational Tracheostomy (PDT)
Technique: Ciaglia technique (most common)
- Bronchoscopic guidance (confirm midline, level between ring 1-2 or 2-3)
- Needle puncture (18G) + syringe aspiration confirms trachea
- Guidewire (Seldinger technique) inserted
- Serial dilators or single tapered dilator (Blue Rhino)
- Tracheostomy tube inserted over guidewire
Alternatives: Griggs (guidewire forceps) · PercuTwist (rotating dilator) · Fantoni (translaryngeal)
Complications:
- Immediate: Bleeding, false passage, tube dislodgement, subcutaneous emphysema
- Early: Infection, tube obstruction, pneumothorax
- Late: Tracheal stenosis, tracheo-innominate fistula (massive bleed), tracheomalacia, scarring
vs Surgical tracheostomy: PDT = bedside, faster, less infection; Surgical = better if anatomy abnormal, obese, emergency, coagulopathy
🔑 MASTER CROSS-LINKS (Exam connectors)
| Pair | Why connected |
|---|---|
| Brachial plexus block → LAST | Always discuss local anesthetic toxicity with any nerve block |
| Difficult airway → AFOI | Predicted difficult = awake technique is safest |
| SADs → CICO algorithm | SADs are Plan B in failed intubation |
| Post-thyroidectomy → RLN + tracheomalacia | Two separate mechanisms of stridor post-op |
| Cricothyroidotomy → CICO | Front-of-neck access = final rescue in CICO |
| SLN block → AFOI | SLN block is one of 4 blocks in AFOI preparation |
📌 QUICK RECALL: HIGH-YIELD NUMBERS
| Fact | Value |
|---|---|
| Mallampati Class III/IV = predicted difficult | ≥ Class III |
| Wilson score cutoff | ≥ 2 |
| Pre-tracheal fat > ? → difficult DL | > 28 mm on USG |
| Intralipid dose in LAST | 1.5 mL/kg 20% IV bolus |
| Dexmedetomidine load for AFOI | 1 mcg/kg over 10 min |
| Needle cricothyroidotomy max duration | 30–45 min |
| SADs oropharyngeal seal pressure (2nd gen) | 25–35 cmH₂O |
| Post-thyroid haematoma: MOST COMMON cause of stridor | Haematoma |
| Hypocalcaemia stridor timing | 24–72 hrs post-op |
Exam tip: Always structure answers as: Definition → Classification/Types → Anatomy/Mechanism → Clinical features → Diagnosis → Management → Complications. Diagrams are mandatory for brachial plexus, AIDAA algorithm, and SAD generations.
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