A 48-year-old woman with a BMI of 34 kg/m² and a history of obstructive sleep apnea presents for pre-anesthetic evaluation before undergoing abdominal hysterectomy. On airway examination, when she opens her mouth and protrudes her tongue, only the soft palate and the base of the uvula are visible. The anterior and posterior tonsillar pillars are not visible. Her thyromental distance is 5.8 cm, and she has limited neck extension due to cervical spondylosis. What is her Mallampati score, and what is the predicted incidence of difficult intubation?

Explanation

## Mallampati Class III: High-Risk Airway This patient demonstrates **Mallampati Class III** anatomy, which carries a significantly elevated risk of difficult intubation. ### Mallampati Classification and Intubation Risk | Class | Visible Structures | Incidence of Difficult Intubation | Risk Category | |-------|-------------------|----------------------------------|---------------| | I | Soft palate, uvula, tonsillar pillars | ~1% | Easy | | II | Soft palate, uvula, partial tonsillar pillars | ~10% | Moderate | | III | Soft palate, base of uvula only | ~60% | Difficult | | IV | Hard palate only | ~90% | Very difficult | **Key Point:** In this patient, visibility is limited to the soft palate and uvula base, with **no visualization of the tonsillar pillars**—the hallmark of **Mallampati Class III**. ### Why This Patient Is High-Risk 1. **Mallampati Class III** anatomy: reduced oropharyngeal space 2. **Thyromental distance 5.8 cm** (borderline; <6 cm is unfavorable) 3. **Limited neck extension** (cervical spondylosis): reduces sniffing position 4. **Obesity (BMI 34)**: increases risk of airway collapse and difficult mask ventilation 5. **History of OSA**: suggests anatomically compromised airway ### Clinical Implications **High-Yield:** Mallampati Class III patients have approximately **60% incidence of difficult intubation** and require: - Awake fiberoptic intubation (gold standard) - Videolaryngoscopy as an alternative - Careful planning for failed airway scenarios - Consideration of regional anesthesia if feasible **Clinical Pearl:** Mallampati assessment is most predictive when combined with other airway parameters. This patient has **multiple unfavorable features** (Class III, reduced thyromental distance, limited neck mobility, obesity, OSA), making her a **high-risk airway** requiring advanced planning. **Mnemonic: LEMON** — assessment of difficult airway: - **L**ook externally (face, jaw, teeth) - **E**valuate 3-3-2 rule (interincisor distance, hyoid-to-mental distance, pharyngeal depth) - **M**allampati score - **O**pen mouth (assess mouth opening) - **N**eck mobility [cite:Gupta & Sharma Textbook of Anesthesiology Ch 4; Miller's Anesthesia 8e Ch 16]