title: The effects of atracurium on bispectral index (BIS) values in dogs anaesthetized with isoflurane.
abstract: Balanced anaesthesia techniques employ specific drugs in addition to general anaesthetics. The potential effect of some of these drugs on the bispectral index (BIS) remains unclear. BIS seems to be unaffected by the administration of neuromuscular blockers while opioids may block nociceptive-induced BIS increases in anaesthetized humans. In this study, the effect of a single dose of atracurium on BIS values was assessed in dogs premedicated with morphine and anaesthetized with isoflurane (1 MAC). Fifteen female dogs undergoing elective ovariohysterectomy were employed. BIS values were recorded before and after the administration of atracurium. These values were then recorded again once the animals were surgically stimulated. The end tidal isoflurane concentration, cardiovascular and respiratory parameters were recorded through the study. Results show that the mean (±SD) BIS values decreased slightly, but significantly (P=0.033) from 67±8.42 to 65±5.84 after the administration of atracurium. Despite significant increase in heart rate and arterial pressure during the surgical phase, the mean BIS values were not modified by ovariohysterectomy. Atracurium appeared to have minimal clinical effect on the BIS in anaesthetized dogs.
authors.affiliation: Departamento de Medicina y Cirugía Animal, Universidad de Murcia, Campus de Espinardo, Espinardo, Murcia 30100, Spain. ebelda@um.es
authors.forename: Eliseo
authors.initials: E
authors.lastname: Belda
authors.forename: Francisco G
authors.initials: FG
authors.lastname: Laredo
authors.forename: Xiomara
authors.initials: X
authors.lastname: Lucas
authors.forename: Amalia
authors.initials: A
authors.lastname: Agut
authors.forename: Mayte
authors.initials: M
authors.lastname: Escobar
authors.forename: Marta
authors.initials: M
authors.lastname: Soler
mesh_terms: D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D000818:Animals; D001279:Atracurium / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D056805:Consciousness Monitors / Q000662:veterinary*; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007044:Hysterectomy / Q000662:veterinary; D007530:Isoflurane / Q000008:administration & dosage*; D009020:Morphine / Q000494:pharmacology; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D010052:Ovariectomy / Q000662:veterinary
chemical_list: D018685:Anesthetics, Inhalation; D003473:Neuromuscular Nondepolarizing Agents; D001279:Atracurium; D009020:Morphine; D007530:Isoflurane