CLINICAL EXPERIENCE GUIDE

Endotracheal Intubation

A Comprehensive Clinical Experience Guide for Emergency, ICU & Operative Settings

MBBS, MD Medicine, DM Cardiology — Professor of Medicine / ICU Intensivist

Airway Anatomy — Sagittal View

Understanding the anatomy is the foundation of safe intubation

Nasal Cavity Oral Cavity Tongue Epiglottis Vallecula Vocal Cords Larynx Trachea ET Tube Path → Cuff (20-30 cmH₂O) Esophagus Thyroid Cart. Cricoid Ring

Indications for Endotracheal Intubation

Absolute Indications

  • • Cardiac Arrest — Secure airway for CPR ventilation
  • • GCS ≤ 8 — Loss of protective airway reflexes
  • • Respiratory Failure — PaO₂ < 60 mmHg despite O₂, PaCO₂ > 50 with acidosis
  • • Airway Obstruction — Angioedema, epiglottitis, foreign body
  • • Impending Airway Loss — Inhalation burns, expanding neck hematoma
  • • Status Epilepticus — Refractory to initial pharmacotherapy

Relative Indications

  • • Hemodynamic Instability — Severe shock requiring airway control
  • • Anticipated Clinical Course — OR procedures, transport of critical patient
  • • Pulmonary Toilet — Inability to clear secretions
  • • Severe Metabolic Acidosis — Fatigue of respiratory compensation
  • • Massive Hemoptysis / GI Bleed — Airway protection
  • • Severe Facial/Neck Trauma — Prophylactic before swelling worsens

Clinical Pearl

"If you're thinking about intubating the patient, you probably should." The decision to intubate is often clinical gestalt — don't wait for blood gas confirmation in a crashing patient.

Pre-Intubation Airway Assessment

LEMON Assessment for Difficult Airway

L
Look Externally

Facial trauma, large incisors, beard/mustache, obesity, short thick neck, large tongue, micrognathia

E
Evaluate 3-3-2 Rule

3 fingers mouth opening (inter-incisor distance), 3 fingers hyomental distance, 2 fingers thyro-hyoid distance

M
Mallampati Score

Patient sitting upright, mouth wide open, tongue protruded without phonation

Class I

Soft palate, fauces, uvula, pillars visible

Class II

Soft palate, fauces, uvula visible

Class III

Soft palate, base of uvula only

Class IV

Hard palate only — Difficult airway

O
Obstruction / Obesity

Supraglottic masses, peritonsillar abscess, epiglottitis. BMI >30 significantly increases difficulty. Neck circumference >40cm predicts difficult intubation.

N
Neck Mobility

C-spine immobilization, ankylosing spondylitis, rheumatoid arthritis, prior cervical fusion. Assess atlanto-occipital extension.

Cormack-Lehane Grading (Laryngoscopic View)

Grade I — Full view

Entire glottic opening visible

Grade II — Partial view

Posterior commissure / arytenoids visible

Grade III — Epiglottis only

No glottic structure seen — use bougie

Grade IV — No structures

Neither glottis nor epiglottis — surgical airway

Equipment Checklist

Tick items as you prepare — never intubate without confirming every item

0 / 0 ready

Step-by-Step Intubation Procedure

Rapid Sequence Intubation (RSI) — Pharmacology

Weight-based dosing. Adjust for hemodynamic status, head injury, and comorbidities.

kg — doses auto-calculate below

Complications & Troubleshooting

Immediate Complications

  • • Esophageal Intubation — #1 feared complication. Confirm with ETCO₂ waveform (gold standard), bilateral auscultation, chest rise, SpO₂ trend. If any doubt — remove tube and re-oxygenate.
  • • Right Mainstem Intubation — Tube advanced too far. Absent left breath sounds. Withdraw 2cm and re-auscultate. CXR confirmation.
  • • Aspiration — Cricoid pressure (Sellick's) during RSI. Suction immediately. Ramped/head-up positioning pre-intubation.
  • • Dental / Soft Tissue Trauma — Avoid using teeth as fulcrum. Lift, don't lever the laryngoscope.
  • • Hypoxemia — Pre-oxygenate adequately. Limit attempts to 30 seconds max. BVM between attempts.
  • • Cardiovascular Collapse — Sympathetic surge → hypertension/tachycardia OR vasovagal/sedation-induced hypotension. Have push-dose epinephrine ready (10 mcg/mL).

Delayed Complications

  • • Ventilator-Associated Pneumonia (VAP) — Head of bed 30-45°, oral chlorhexidine, daily sedation vacation, SBT protocols
  • • Subglottic Stenosis — Prolonged intubation >14 days. Consider tracheostomy timing.
  • • Tracheomalacia — Cuff pressure monitoring q8h (maintain 20-30 cmH₂O)
  • • Vocal Cord Paralysis — Recurrent laryngeal nerve injury. Hoarseness post-extubation. ENT evaluation.
  • • Post-Extubation Stridor — Cuff leak test before extubation. Dexamethasone 8mg IV q8h × 3 doses if high risk.

Failed Airway Algorithm (CICV — Can't Intubate, Can't Ventilate)

  1. 1. Call for help — Anesthesia, ENT, senior colleague
  2. 2. Supraglottic device — LMA / i-gel as rescue
  3. 3. Cricothyrotomy — Scalpel-bougie-tube technique. Palpate cricothyroid membrane. Vertical skin incision → horizontal stab through membrane → bougie → 6.0 ETT
  4. 4. Needle cricothyrotomy (pediatric) — 14G angiocath through CTM → jet ventilation

Clinical Pearls from the Bedside