title: Reduction of the minimum alveolar concentration of isoflurane in dogs using a constant rate of infusion of lidocaine-ketamine in combination with either morphine or fentanyl.
abstract: The objective of this study was to determine the effects of a constant rate of infusion of lidocaine and ketamine in combination with either morphine or fentanyl on the minimum alveolar concentration of isoflurane (MAC(ISO)) during ovariohysterectomy in dogs. Female dogs (n=44) were premedicated with acepromazine and midazolam. Anaesthesia was induced with propofol and maintained with isoflurane. Dogs received ketamine (0.6 mg/kg/h) and lidocaine (3 mg/kg/h) together with morphine (0.24 mg/kg/h; MLK) or fentanyl (0.0036 mg/kg/h; FLK). The control group received Ringer's lactate solution. A skin incision was used as the noxious stimulus. The MAC(ISO) value was obtained with Dixon's up-and-down method. MAC(ISO) was 0.7±0.0 vol.% in the control group, 0.3±0.0 vol.% in the MLK group (45% MAC reduction) and 0.0±0.0 vol.% in the FLK group (97% MAC reduction). A combination of fentanyl with lidocaine and ketamine decreased the MAC(ISO) in dogs; this decrease was more pronounced than that produced by morphine, lidocaine and ketamine.
authors.affiliation: Department of Animal Medicine and Surgery, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain.
authors.forename: Delia
authors.initials: D
authors.lastname: Aguado
authors.forename: Javier
authors.initials: J
authors.lastname: Benito
authors.forename: Ignacio A
authors.initials: IA
authors.lastname: Gómez de Segura
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology; D000777:Anesthetics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D004338:Drug Combinations; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000494:pharmacology*; D007044:Hysterectomy / Q000662:veterinary; D007530:Isoflurane / Q000008:administration & dosage / Q000493:pharmacokinetics*; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D010052:Ovariectomy / Q000662:veterinary; D011650:Pulmonary Alveoli / Q000378:metabolism*
chemical_list: D000701:Analgesics, Opioid; D000777:Anesthetics; D004338:Drug Combinations; D007649:Ketamine; D009020:Morphine; D008012:Lidocaine; D007530:Isoflurane; D005283:Fentanyl