title: Electroencephalogram-based indices applied to dogs' depth of anaesthesia monitoring.
abstract: Hypnotic drug administration causes alterations in the electroencephalogram (EEG) in a dose-dependent manner. These changes cannot be identified easily in the raw EEG, therefore EEG based indices were adopted for assessing depth of anaesthesia (DoA). This study examines several indices for estimating dogs' DoA. Data (EEG, clinical end-points) were collected from 8 dogs anaesthetized with propofol. EEG was initially collected without propofol. Then, 100 ml h⁻¹ (1000 mg h⁻¹) of propofol 1% infusion rate was administered until a deep anaesthetic stage was reached. The infusion rate was temporarily increased to 200 ml h⁻¹ (2000 mg h⁻¹) to achieve 80% of burst suppression. The index performance was accessed by correlation coefficient with the propofol concentrations, and prediction probability with the anaesthetic clinical end-points. The temporal entropy and the averaged instantaneous frequency were the best indices because they exhibit: (a) strong correlations with propofol concentrations, (b) high probabilities of predicting anaesthesia clinical end-points.
authors.affiliation: Institute of Electronics and Informatics Engineering of Aveiro (IEETA), Departamento de Electrónica, Telecomunicações e Informática, Universidade de Aveiro, Aveiro, Portugal. Electronic address: susana.bras@ua.pt.
authors.forename: S
authors.initials: S
authors.lastname: Brás
authors.affiliation: Esthesys Ltd, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Georgakis
authors.affiliation: Hospital Veterinário do Porto (HVP), Porto, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Ribeiro
authors.affiliation: Research Center for Biosciences & Health Technologies, Universidade Lusófona de Humanidade e Tecnologia, Lisboa, Portugal.
authors.forename: D A
authors.initials: DA
authors.lastname: Ferreira
authors.affiliation: Rede de quimica e tecnologia (REQUIMTE), Faculdade de farmácia da universidade do porto (FFUP), Porto, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Silva
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAD), Veterinary Sciences Department, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5001-801 Vila Real, Portugal; Institute of Molecular and Cell Biology (IBMC), Porto, Rua do Campo Alegre, n° 823, 4150-180 Porto, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Antunes
authors.affiliation: Departamento de Ciências e Tecnologia, Universidade Aberta, Delegação do Porto, Portugal; Centro de Investigação Clínica em Anestesiologia, Serviço de Anestesiologia, Centro Hospitalar do Porto, Portugal.
authors.forename: C S
authors.initials: CS
authors.lastname: Nunes
mesh_terms: D000758:Anesthesia / Q000662:veterinary*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D000818:Animals; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring / Q000662:veterinary*; D004569:Electroencephalography / Q000187:drug effects / Q000379:methods / Q000662:veterinary*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D015742:Propofol / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D018686:Anesthetics, Intravenous; D006993:Hypnotics and Sedatives; D015742:Propofol
keywords: Depth of anaesthesia; Dog; EEG; Entropy; Instantaneous frequency