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Write a short note on Cormack–Lehane Classification.

General Surgery · Final Professional

Definition

The Cormack–Lehane classification grades the view of the larynx obtained at direct laryngoscopy. Unlike the Mallampati score (a bedside prediction), Cormack–Lehane describes what is actually seen during laryngoscopy, and is used to document the airway and predict/record difficulty.

Grades

Grade 1:

most of the glottis (vocal cords) is visible.
Grade 2: only the posterior part of the glottis/arytenoids is seen.
Grade 3: only the epiglottis is visible (no glottis).
Grade 4: neither the glottis nor the epiglottis is seen. Grade 2 is often subdivided into 2a and 2b.
Grades 3 and 4 signify a difficult intubation.

CLINICAL PEARL

Distinguish the two scores: Mallampati is a pre-operative prediction (mouth open, tongue out), whereas Cormack–Lehane is the actual view at laryngoscopy. A grade-3 view (epiglottis only) is the classic indication for a bougie.

Improving the View

When the initial Cormack–Lehane view is poor, several manoeuvres can improve it before abandoning the attempt: optimising the head position, external laryngeal manipulation (the ‘burp’ manoeuvre — backward, upward, rightward pressure on the thyroid cartilage), using a different or longer blade, and switching to a videolaryngoscope. Documenting the best view achieved, and how it was obtained, is valuable information for anyone anaesthetising the patient in future.

WHY It Matters & its Limitations

The Cormack–Lehane grade is valuable because it records the reality of the laryngoscopy rather than a prediction, guiding the immediate choice of aid (a bougie for a grade-3 view, escalation to videolaryngoscopy or a supraglottic airway for grade 4) and warning future anaesthetists of difficulty. Its limitations are that it depends on the operator, the blade and the manoeuvres used (external laryngeal pressure or a different position can improve the grade), and that it describes only the view, not the ease of actually passing the tube — so it is always documented together with how the view was obtained and how intubation was ultimately achieved.

DANGER / REMEMBER

Do not treat a poor Cormack–Lehane view as a reason for repeated forceful attempts: optimise the view once (position, external laryngeal manipulation, videolaryngoscope, bougie) and, if intubation still fails, move on through the difficult-airway algorithm while keeping the patient oxygenated, because repeated laryngoscopy causes the trauma that turns difficulty into disaster.

Graded at laryngoscopy — unlike Mallampati which is a bedside predictor.

Grade	View at laryngoscopy	Difficulty
1	Full glottis visible	Easy
2	Posterior glottis / arytenoids only	Usually easy
3	Epiglottis only	Difficult
4	No glottic structures; soft palate only	Very difficult

KEY POINT

Key points TO remember

Cormack–Lehane = the actual laryngoscopic view (not a bedside prediction).
1 full glottis → 2 posterior glottis → 3 epiglottis only → 4 neither.
Grades 3–4 = difficult intubation; grade 3 is the classic bougie situation.
Complements Mallampati (which predicts before laryngoscopy).

EXAM TIP

Sources: Morgan & Mikhail’s Clinical Anesthesiology; Miller’s Anesthesia; Ajay Yadav’s Short Textbook of Anaesthesia.

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