Clinical Application of Ultrasound-Guided Internal Branch of Superior Laryngeal Nerve Block in Patients with Severe COPD Undergoing Awake Fibreoptic Nasotracheal Intubation: A Randomized Controlled Clinical Trial

Purpose: The aim was to investigate the time for intubation, adverse events and the comfort score of ultrasound-guided internal branch of superior laryngeal nerve block in patients with severe chronic obstructive pulmonary disorder (COPD) undergoing awake fibreoptic nasotracheal intubation. Methods: Sixty patients with COPD who needed awake fibreoptic nasotracheal intubation were randomly and evenly divided into the ultrasound-guided internal branch of the superior laryngeal nerve block group (group S) and the control group (group C). All patients received procedural sedation with dexmedetomidine and adequate topical anaesthesia of the upper respiratory tract. Then, bilateral block was performed (with 2 mL of 2% lidocaine or the same volume of saline) followed by fibreoptic nasotracheal intubation. The primary outcomes were time for intubation, adverse reactions and comfort score. The secondary outcomes were haemodynamic changes and serum norepinephrine (NE) and adrenaline (AD) concentrations immediately before intubation (T0); immediately after intubation to the laryngopharynx (T1); and immediately (T2), 5 min (T3) and 10 min (T4) after intubation between the groups. Results: Compared with group C, the time for intubation, the incidence of adverse reactions and the comfort score in group S were significantly lower ( P < 0.01). Compared with T0, the mean arterial pressure (MAP), heart rate (HR), NE and AD were significantly higher at T1 - T4 in group C ( P < 0.05), but were not obviously higher at T1 - T4 in group S ( P > 0.05). MAP, HR, NE and AD at T1–T4 were significantly lower in group S than in group C ( P < 0.05). Conclusion: Ultrasound-guided internal branch of the superior laryngeal nerve block can effectively shorten the time for intubation, reduce the incidence of adverse reactions, improve comfort score, maintain considerable haemodynamic stability and inhibit stress response in patients with severe COPD undergoing awake fibreoptic nasotracheal intubation. Keywords: COPD, awake fibreoptic nasotracheal intubation, the time for intubation, stress response, ultrasound-guided the internal branch of the superior laryngeal nerve block