Bronchoconstrictive and relaxant effects of lidocaine on the airway in dogs.
OBJECTIVE
Intravenous lidocaine commonly is used to treat ventricular arrhythmias and to attenuate reflex airway constriction and intracranial pressure elevation during airway manipulation in intensive care units. There is much controversy as to the actions of lidocaine on the airway, so the aim of this study was to compare, in detail, the actions of lidocaine with those of bupivacaine and procaine on airway caliber and the associated changes in plasma catecholamine concentrations in the dog.


METHODS
Prospective, randomized, controlled experimental in vivo and in vitro study.


METHODS
A university research laboratory.


METHODS
Mongrel dogs.


METHODS
In the first experiment, we evaluated the effects of intravenous local anesthetics--lidocaine 0-10 mg/kg (n = 7), bupivacaine 0-2.5 mg/kg (n = 7), or procaine 0-20 mg/kg (n = 7)--on basal airway tone. In second experiment, histamine (10 microg/kg + 500 microg x kg(-1) x hr(-1), n = 6), serotonin (10 microg/kg + 500 microg x kg(-1) x hr(-1), n = 7), and methacholine (0.5 microg/kg + 300 microg x kg(-1) x hr(-1), n = 7) were infused to determine the effects of lidocaine (0-10 mg/kg) on agonist-induced bronchoconstriction. In addition, the actions of lidocaine on vagal nerve stimulation were examined (n = 7).


RESULTS
Bronchial cross-sectional area at the third bronchial bifurcation of dogs was monitored continuously through a fiberoptic bronchoscope. In the first experiment, all local anesthetics produced a dose-dependent decrease in basal bronchial cross-sectional area. In the second experiment, lidocaine significantly potentiated histamine and serotonin-induced bronchoconstriction. In contrast, lidocaine antagonized methacholine- and vagal nerve stimulation-induced bronchoconstriction.


CONCLUSIONS
We have clearly demonstrated that lidocaine may produce direct bronchoconstriction and worsen some agonist-induced bronchoconstriction, but it prevents reflex airway constriction. Therefore, we suggest that this agent be used with caution in asthmatics.
Hirota
K
K
Department of Anesthesiology, University of Hirosaki, School of Medicine, Hirosaki, Japan.
Hashimoto
Y
Y
Sato
T
T
Yoshioka
H
H
Kudo
T
T
Matsuki
A
A
Lambert
D G
DG
D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001980:Bronchi / Q000187:drug effects*; D016084:Bronchoconstriction / Q000187:drug effects*; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D001993:Bronchodilator Agents / Q000494:pharmacology; D001999:Bronchoscopy; D002045:Bupivacaine / Q000494:pharmacology; D002395:Catecholamines / Q000097:blood; D004285:Dogs; D004347:Drug Interactions; D005336:Fiber Optic Technology; D006632:Histamine / Q000009:adverse effects; D008012:Lidocaine / Q000494:pharmacology*; D011343:Procaine / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000187:drug effects
D000779:Anesthetics, Local; D000889:Anti-Arrhythmia Agents; D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents; D002395:Catecholamines; D011976:Receptors, Muscarinic; D011343:Procaine; D006632:Histamine; D008012:Lidocaine; D002045:Bupivacaine