Cardiovascular responses and lidocaine absorption in fiberoptic-assisted awake intubation

Local anesthetic toxicity and cardiovascular stress during fiberoptic-assisted awake tracheal intubation were assessed prospectively in 20 patients with airway management problems. Cardiovascular responses, dose of lidocaine, its systemic absorption, and patient comfort were measured. A standardized topical anesthesia protocol of 4% lidocaine aerosol, topical 2% lidocaine viscous gel, and direct perbronchoscopic laryngeal application was used. Awake intubation produced no significant elevation of blood pressure or pulse rate either during the topical application or after the intubation. Despite a large total dose of topical lidocaine (5.3 +/- 2.1 mg/kg), the mean peak arterial plasma lidocaine concentration was low (0.6 +/- 2.1 micrograms/ml). Patient comfort assessment showed that nine patients had no discomfort, whereas 11 had minimal discomfort. Supplementary sedation used was minimal (fentanyl, 1.4 +/- 0.6 micrograms/kg, and diazepam, 1.9 +/- 1.8 mg). This method of producing topical anesthesia for awake tracheal intubation is recommended as a safe, easy, and comfortable method of managing patients with airway difficulties.