Aerosolized lidocaine reduces dose of topical anesthetic for bronchoscopy

Conventional aerosol techniques were used to determine if inhalation of lidocaine can supplement topical anesthesia applied during bronchoscopy. Aerosols of either saline or lidocaine (50 mg at either 2 or 4% concentrations) were generated by jet nebulizer and administered with or without intermittent positive-pressure breathing. Patients (n = 38) after aerosol inhalation were administered 2% lidocaine (atomized and instilled) for suppression of the gag reflex, control of cough, and airway anesthesia. For five of the patients, prior to bronchoscopy, additional studies with radioaerosols and scintillation scans were accomplished with the same aerosol methodology to demonstrate lung distribution of deposited aerosol. For five patients who received 2% lidocaine aerosol prior to bronchoscopy, the subsequent topical dose of anesthetic required for the procedure was 186 +/- 34 (SEM) mg lidocaine. Nine patients in a control group received saline aerosol and required significantly more anesthetic, i.e., 308 +/- 26 mg; procedures were completed on average within 50 min. The largest difference was in the amount delivered to the upper airway (naris, pharynx, epiglottis, and larynx), i.e., 144 +/- 26 mg for saline control versus 48 +/- 16 mg for lidocaine aerosol protocol. Airways distal to the cords required less anesthesia also, on average, 77 mg for the saline control versus 46 mg for the lidocaine aerosol protocol (p < 0.05). Topical anesthetic dosage data were replicated in 12 additional patients studied by a different bronchoscopist. No additional benefit was afforded by premedication with 4% lidocaine aerosol rather than the 2% aerosol (n = 12). We conclude that aerosol modalities can supplement topical anesthesia during bronchoscopy, primarily by reducing the dose required to anesthetize the upper airway.