Reduced Systemic Absorption of Intrabronchial Lidocaine by High‐Frequency Nebulization

Abstract

Serum lidocaine concentrations were measured in a series of patients during and after topical administration of lidocaine used to anesthetize the nasal mucosa, pharynx, and larynx for diagnostic fiberoptic bronchoscopy. In one group of patients (N = 9) the trachea and bronchi were sprayed with a 2% lidocaine solution administered in 2 mL volumes. Another group (N = 14) received a 2% lidocaine solution which was administered by inhalation of lidocaine dispensed by a high-frequency nebulizer. Multiple serum samples drawn over a 1-hour period were analyzed by gas chromatography with nitrogen-phosphorous detection. In the spray group versus the inhalation group, there were no differences in mean age (54 vs 55 years), total lidocaine dose (572 vs 525 mg), or time of peak serum lidocaine concentration (43 vs 41 minutes after dose). However, the peak serum lidocaine concentrations were significantly lower in the inhalation group vs the spray group (1.40 vs 3.63 micrograms/mL). Thus, administration of lidocaine via inhalation by ultrasonic nebulization results in lower peak serum concentrations, and a reduction in the likelihood of toxicity, than when administered by conventional topical spray.

Clinical effects and pharmacokinetics of nebulized lidocaine in healthy horses

“…There was no difference in the cumulative number of stimulations across 10 sites within the pharynx and larynx needed to induce swallowing prior to or following lidocaine nebulization. Nebulized lidocaine has been used in human medicine to anesthetize the nasal mucosa, pharynx, and larynx prior to bronchoscopy, as well as ancillary therapy to minimize postoperative laryngospasm in children and adults ( 27 , 28 ). In addition, topical lidocaine minimizes cough during bronchoscopy and BAL in horses ( 29 ).…”

Pharmacokinetics of Lidocaine and Its Metabolites Following Vaginal Administration of Lidocaine Gel to Healthy Female Subjects

“…Nebulized lidocaine into the pulmonary vasculature resulted in approximately 60% lower lidocaine peak serum concentrations compared with the spray administration (mean concentrations; 1.4 vs 3.6 µg/mL, respectively). 5 Of note, clinical signs of overt lidocaine toxicity were not observed in either dose group (total N = 25). The authors conclude that a better safety margin is established with administration of a nebulized formulation vs a spray preparation based on peak serum concentrations.…”

“…In subsequent work, lidocaine systemic exposure administered by high‐frequency nebulization was compared to spray administration to the trachea and bronchi. Nebulized lidocaine into the pulmonary vasculature resulted in approximately 60% lower lidocaine peak serum concentrations compared with the spray administration (mean concentrations; 1.4 vs 3.6 µg/mL, respectively) . Of note, clinical signs of overt lidocaine toxicity were not observed in either dose group (total N = 25).…”

A case report of an 18-year-old receiving nebulized lidocaine for treatment of COVID-19 cough

“…In all of these studies, the highest serum lidocaine level obtained was 1.4 mcg/mL, with most results being <1 mcg/mL. 29 , 30 , 31 , 32 This is far below the 5 mcg/mL level above which the risk for toxicity is significantly increased. 13 Although it has not been previously reported that nebulized lidocaine causes toxicity, we believe it is warranted to monitor for signs and symptoms of lidocaine toxicity as well as serum levels in patients receiving scheduled doses.…”