Absorption of lidocaine during aspiration anesthesia of the airway

British Thoracic Society guideline for diagnostic flexible bronchoscopy in adults: accredited by NICE

“…A randomised spray-as-you-go study, comparing the same volume of 1% and 2% lidocaine (delivered to the larynx and tracheobronchial tree), found no difference in subjective and objective measures of cough suppression 136. Another randomised study compared similar volumes of 1%, 1.5% and 2% lidocaine trickled onto the back of the patient's tongue, which was allowed to be aspirated into the larynx 137. Although a relatively small study, 1% was found to be equally efficacious at cough suppression and had similar requirements for additional lidocaine during bronchoscopy.…”

“…Peak serum concentrations usually occur from 20 to 45 min after topical application,137 – 139 although concentrations of active (but less potent) metabolites (eg, monoethylglycinexylidide) continue to rise for at least 2 h 140. Several studies have examined the maximal safe dose of lidocaine, with conflicting results.…”

Efficacy of oropharyngeal lidocaine instillation on hemodynamic responses to orotracheal intubation

“…Lidocaine instilled onto the back of the tongue provides effective topical anesthesia for awake fiberoptic intubation [9,10]. It was found that the lidocaine solution could pool in the pharynx and then flow over the interarytenoid notch into the trachea [9].…”

Monitoring, Sedation, and Anesthesia for Flexible Fiberoptic Bronchoscopy

“…There are relatively few studies examining the optimal lidocaine dosing for patient comfort and safety during FFB. A study examining various lidocaine amounts (mg/kg) and strengths ranging from 1% to 2% in 96 patients found no differences between the six groups in terms of patient comfort (Mainland et al, 2001). The author recommended use of 1% lidocaine for topical airway anesthesia based on similar amounts of supplemental lidocaine doses and serum lidocaine levels.…”

“…These studies evaluating lidocaine dosing have been done to evaluate a variety of techniques in application of topical anesthesia (Ameer et al, 1989;Amitai et al, 1990, Berger et al, 1989Boye & Bresden, 1979;Efthimiou et al, 1982;Gjonaj et al, 1997;Gomez et al, 1983;Jones et al, 1982;Karvonen et al, 1976;Korttila et al, 1981;Langmack et al, 2000;Le Lorier et al, 1979;Loukides et al, 2000;Mainland et al, 2001;McBurney et al, 1984;Milman et al, 1998;Patterson et al, 1975;Smith et al, 1985;Sucena et al, 2004;Sutherland et al, 1985). These twenty studies were reviewed by Frey et al in their study of lidocaine dosing (Frey et al, 2008).…”