A 42-year-old male with a history of epiglottitis 2 years ago (treated conservatively) presents for emergency appendicectomy. On airway assessment, the patient has a Mallampati score of III, inter-incisor distance of 3 cm, and thyromental distance of 6 cm. Awake fiberoptic intubation is planned. During the procedure, after topicalization with 4% lignocaine spray and 10% lignocaine gel, the patient develops sudden onset of stridor and respiratory distress. Which of the following is the MOST likely cause of this acute deterioration?

Explanation

## Acute Stridor During Awake Fiberoptic Intubation **Correct Answer: Laryngospasm triggered by inadequate topicalization** In this clinical scenario, the patient develops acute stridor and respiratory distress during awake fiberoptic intubation despite topical anesthesia. The key clue is that stridor develops during instrumentation—this is classic for **laryngospasm**. ### Why Laryngospasm is the Answer: **Key Point:** Laryngospasm is a protective airway reflex that occurs when the superior laryngeal nerve (external branch) and recurrent laryngeal nerve are stimulated inadequately anesthetized mucosa. It is the most common cause of acute airway obstruction during awake intubation procedures. **Clinical Features of Laryngospasm:** - Sudden onset stridor (inspiratory or biphasic) - Respiratory distress during manipulation - Occurs despite topical anesthesia if coverage is incomplete - More common in patients with recent upper airway inflammation (epiglottitis history) - Reflex nature: occurs within seconds of trigger **Why Inadequate Topicalization?** - The posterior pharynx and laryngeal inlet require meticulous topicalization - 4% lignocaine spray alone may not achieve adequate depth of anesthesia - The patient's difficult airway (Mallampati III, small inter-incisor distance) makes instrumentation more traumatic - History of epiglottitis may have left residual mucosal sensitivity - Fiberoptic manipulation of the arytenoids and vocal cords without adequate block triggers the reflex **Management:** Immediate cessation of manipulation, 100% oxygen, positive pressure ventilation if needed, and consideration of IV succinylcholine if laryngospasm persists (though prevention is superior). --- **High-Yield Mnemonic: LARS** - **L**aryngeal reflex - **A**cute onset - **R**espiratory distress - **S**tridor (inspiratory) **Clinical Pearl:** Awake fiberoptic intubation requires bilateral superior laryngeal nerve blocks (SLN blocks) + recurrent laryngeal nerve blocks + topical spray for optimal prevention of laryngospasm.