title: Effects of intravenous lidocaine on isoflurane concentration, physiological parameters, metabolic parameters and stress-related hormones in horses undergoing surgery.
abstract: Physiological parameters, metabolic parameters and stress-related hormones are evaluated in horses anaesthetized with isoflurane in oxygen combined with lidocaine intravenously. Two groups of horses anaesthetized with isoflurane (six horses in each group) were studied: a lidocaine group (IL), which received intravenous lidocaine and a control group (C), which received intravenous saline. Horses in both groups were premedicated with detomidine (i.v.), and anaesthesia was induced with midazolam-ketamine (i.v.). The lidocaine group received intravenous lidocaine as a loading dose of 2.5 mg kg(-1) at 15 min after induction of anaesthesia directly followed by a maintenance dosage of 50 microg kg(-1) min(-1), while the control group received saline (i.v.) following the same regime. End-tidal isoflurane and standard physiological parameters were measured. Blood was sampled for measurement of lidocaine, stress hormones and metabolic parameters. The end-tidal isoflurane concentration in the lidocaine group was 0.96 +/- 0.06% versus 1.28 +/- 0.06% (mean +/- SD) in the control group, a significant (P < 0.05) reduction of 25%. No significant differences were found regarding stress-related hormones, metabolic and physiological parameters. This study suggests that the use of lidocaine to decrease the concentration of isoflurane to obtain a sufficient surgical anaesthesia has no subsequent effects on physiological and metabolic parameters or stress-related hormones.
authors.affiliation: Section of Veterinary Anaesthesiology, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
authors.forename: T B
authors.initials: TB
authors.lastname: Dzikiti
authors.forename: L J
authors.initials: LJ
authors.lastname: Hellebrekers
authors.forename: P
authors.initials: P
authors.lastname: van Dijk
mesh_terms: D000758:Anesthesia / Q000662:veterinary*; D000777:Anesthetics / Q000494:pharmacology*; D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D004347:Drug Interactions; D004798:Enzymes / Q000097:blood*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006736:Horses; D006854:Hydrocortisone / Q000097:blood; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood; D007530:Isoflurane / Q000493:pharmacokinetics*; D007649:Ketamine; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D008874:Midazolam; D018482:Muscle, Skeletal / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D013312:Stress, Physiological / Q000097:blood*; D013522:Surgery, Veterinary / Q000379:methods
chemical_list: D000777:Anesthetics; D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D004798:Enzymes; D007328:Insulin; D007649:Ketamine; D008012:Lidocaine; D007530:Isoflurane; D008874:Midazolam; D006854:Hydrocortisone