title: Pulmonary uptake of ropivacaine and levobupivacaine in rabbits.
abstract: Local anesthetic toxicity produced by an inadvertent IV injection is attenuated by the pulmonary uptake of local anesthetics. We compared the pulmonary uptake of ropivacaine and levobupivacaine after a bolus injection in rabbits. Sixteen anesthetized rabbits were randomly assigned to either a ropivacaine group or a levobupivacaine group. A bolus containing ropivacaine or levobupivacaine 0.5 mg/kg and indocyanine green (an intravascular indicator) 0.25 mg/kg was injected rapidly into the vena cava. Arterial blood samples were collected serially at 1.2-s intervals for 30 s. Concentrations of local anesthetic and indocyanine green in each sample were determined for the calculation of first-pass uptake of a local anesthetic in the lung. The first-pass uptake of levobupivacaine (31.4% +/- 8.3%; mean +/- SD) was larger than that of ropivacaine (22.9% +/- 5.6%), and the maximum arterial concentration of ropivacaine (21.2 +/- 2.8 micro g/mL) was larger than that of levobupivacaine (18.6 +/- 1.9 micro g/mL). We conclude that the pulmonary uptake of levobupivacaine is larger than that of ropivacaine after a bolus injection. Therefore, the advantages of ropivacaine over levobupivacaine in terms of less cardiovascular toxicity may be offset by the smaller pulmonary uptake after an inadvertent IV injection.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Ohmura
authors.forename: Akiko
authors.initials: A
authors.lastname: Sugano
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kawada
authors.forename: Ken
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D000465:Algorithms; D000577:Amides / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000758:Anesthesia; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000818:Animals; D001711:Biotransformation; D004396:Coloring Agents; D007208:Indocyanine Green; D007267:Injections; D007275:Injections, Intravenous; D008168:Lung / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D000077212:Ropivacaine; D013237:Stereoisomerism
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D004396:Coloring Agents; D000077212:Ropivacaine; D007208:Indocyanine Green