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The Pharmacokinetics of Atomized Lidocaine Administered via the Trachea: A Randomized Trial

Takaenoki, Yumiko MD; Masui, Kenichi MD, PhD; Oda, Yutaka MD, PhD; Kazama, Tomiei MD, PhD

doi: 10.1213/ANE.0000000000001317
Anesthetic Clinical Pharmacology: Research Report

BACKGROUND: Under emergent conditions, endotracheal drug administration may be an effective method of delivering emergency drugs. A common technique is to administer these drugs using a nonatomized spray. Atomized drug delivery may be an attractive alternative to nonatomized delivery because atomized particles are small, cover a large surface area, and may better adhere to endotracheal membrane resulting in more effective drug absorption. In this study, we compared the pharmacokinetic profile of lidocaine administered into the trachea using an atomized or a nonatomized technique.

METHODS: Twenty patients were anesthetized using propofol and remifentanil. Ten minutes after rocuronium was administered, patients received 4% lidocaine (2 mg/kg) intratracheally over 2 seconds before tracheal intubation. Ten patients received atomized lidocaine using a mucosal atomization device, and the other 10 patients received nonatomized lidocaine using a traditional spray tube. Arterial lidocaine plasma concentrations were measured before; at 1, 3, 5, 7, 10, 15, 20, 30, 45, and 60 minutes; and then every 60 minutes after the administration of lidocaine until the end of the operation. We developed a pharmacokinetic model to examine whether bioavailability or absorption rate was different between atomized versus nonatomized lidocaine administration. The total body clearance was fixed at a published value to determine the bioavailability.

RESULTS: Peak plasma concentrations were larger using the mucosal atomization device (median [range]: 1.9 [1.4−3.2] μg/mL) than the spray tube (1.1 [0.6−2.0] μg/mL; P = 0.0021). Our pharmacokinetic model estimated a difference of bioavailability between the atomized and the nonatomized lidocaine (0.801 and 0.559 respectively, P = 0.0005), whereas our model estimated no difference in the absorption rate constant (0.00688/min).

CONCLUSIONS: Our results suggest that when using atomized delivery of lidocaine, less drug is required to achieve a near equivalent plasma lidocaine concentration. Atomized drug administration may be a more efficient method for endotracheal drug administration.

Published ahead of print April 15, 2016

From the *Department of Anesthesiology, National Defense Medical College, Saitama, Japan; and Department of Anesthesiology, Osaka City University, Osaka, Japan.

Yutaka Oda, MD, PhD, is currently affiliated with the Department of Anesthesiology, Osaka City General Hospital, Osaka, Japan.

Accepted for publication February 22, 2016.

Published ahead of print April 15, 2016

Funding: Departmental.

The authors declare no conflicts of interest.

This report was previously presented, in part, at the Euroanaesthesia, Paris, France, June 10, 2012, which was the subject of an article in European Journal of Anaesthesiology 2012;29(suppl):133.

Reprints will not be available from the authors.

Address correspondence to Kenichi Masui, MD, PhD, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama, Japan 359–8513. Address e-mail to

© 2016 International Anesthesia Research Society