In Vivo Lung Uptake of Lidocaine in Pigs

Abstract

A mixture of 14C-labelled lidocaine and indocyanine green dye (IG) (Cardiogreen) was injected as a bolus into the pulmonary artery in pigs (15-25 kg). Time-concentration curves for both substances were constructed from 20s blood samples taken from the common carotid artery for approximately 20s. The extraction of lidocaine in each sample and the 95% first passage uptake (FPU) were calculated, assuming that IG is inert with respect to the lung and that it remains within the vascular compartment. The IG curves were also used to calculate cardiac output. The acid-base status and arterial blood pressure or ECG were also followed. Each animal was given two injections. When 0.5 mg/kg b.w. lidocaine was injected, FPU was 41 +/- 3%; at a dose of 2 mg/kg b.w., FPU was 28 +/- 3% (P less than 0.05). The initial extraction during the first 2 s after appearance of the substances was approximately 80%. This level declined with subsequent samples, and the decline was equally rapid at both dose levels.

Regional Distribution Of11c-Labeled Lidocaine, Bupivacaine, and Ropivacaine in the Heart, Lungs, and Skeletal Muscle of Pigs Studied With Positron Emission Tomography

“…However, the rapid uptake by the lung is also accompanied by a rapid release of drug back into the circulation, such that the lung's initial buering eect is completed by 10±15 s after the injection is made. 38 These ®ndings are similar to those seen in the radioactivities of the lung in the current study (Figure 4). Peak lung radioactivities occurred immediately after the injections.…”

“…It has been demonstrated in pigs and man that a large fraction of lidocaine in the blood is rapidly taken up by the lungs. 38 This rapid, initial uptake after iv injection may play a role in buering the exposure of the brain and heart to large concentrations of local anesthetic after intravenous administration. However, the rapid uptake by the lung is also accompanied by a rapid release of drug back into the circulation, such that the lung's initial buering eect is completed by 10±15 s after the injection is made.…”

Pulmonary Uptake of Ropivacaine and Levobupivacaine in Rabbits

“…The time has been previously used for the calculation of the pulmonary FPU of lidocaine (12,13), narcotic analgesics (19), and propofol (20). By using this time for the calculation, FPU could be compared regardless of CO. Rothstein et al (14) calculated the pulmonary FPU of bupivacaine by the doubleindicator dilution method, as was used in this study.…”

“…1). The first-pass uptake (FPU) of a local anesthetic in the lung was measured by the double-indicator dilution method reported by Bertler et al (12). It was calculated by the formula…”

“…The uptake of a large number of drugs, including local anesthetics, is one of them (11)(12)(13)(14). As a result, the lung has a dampening effect on the arterial concentrations of accidentally injected local anesthetics (12)(13)(14), and the extent of pulmonary uptake may influence the occurrence of local anesthetic toxicity. The pulmonary uptake of a local anesthetic depends mainly on its physicochemical properties (15).…”