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Rucinque DS, Velarde A, Xercavins A, Varvaró-Porter A, Gibson TJ, Michel V, Contreras-Jodar A. Alternatives to Carbon Dioxide in Two Phases for the Improvement of Broiler Chickens' Welfare during Stunning. Animals (Basel) 2024; 14:486. [PMID: 38338133 PMCID: PMC10854911 DOI: 10.3390/ani14030486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/12/2024] Open
Abstract
This study evaluated the exposure to gas mixtures of carbon dioxide (CO2) associated with nitrogen (N2) as alternatives to CO2 in two phases to improve the welfare of broiler chickens at slaughter. Broilers were exposed to one of three treatments: 40C90C (1st phase: <40% CO2 for 2 min; 2nd phase: >90% CO2 and <2% O2 for 2 min, n = 92), 40C60N (40% CO2, 60% N2, and <2% O2 for 4 min, n = 79), or 20C80N (20% CO2, 80% N2, and <2% O2 for 4 min, n = 72). Brain activity (EEG) was assessed to determine the onset of loss of consciousness (LOC) and death. Behavioural assessment allowed for characterisation of an aversive response to the treatments and confirmed loss of posture (LOP) and motionlessness as behavioural proxies of LOC and brain death in 40C60N and 20N80C. However, the lack of quality of the EEG traces obtained in 40C90C did not allow us to determine the onset of LOC and brain death for this treatment. The onset of LOC in 40C60N was found at 19 s [14-30 s] and in 20C80N at 21 s [16-37 s], whereas a LOP was seen at 53 s [26-156 s] in 40C90C. Birds showed brain death in 40C60N at 64 s [43-108 s] and in 20C80N at 70 s [45-88 s]), while they became motionless in 40C90C at 177 s [89-212 s]. The 40C90C birds not only experienced more events of aversive behaviours related to mucosal irritation, dyspnoea, and breathlessness during induction to unconsciousness but were at risk of remaining conscious when the CO2 concentration was increased in the 2nd phase (known to cause severe pain). From an animal welfare point of view, 40C60N proved to be the least aversive of the three treatments tested, followed by 20C80N and 40C90C.
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Affiliation(s)
- Daniel Santiago Rucinque
- Animal Welfare Program, Institute of Agrifood Research and Technology (IRTA), 17121 Monells, Spain; (D.S.R.); (A.V.); (A.X.); (A.V.-P.)
| | - Antonio Velarde
- Animal Welfare Program, Institute of Agrifood Research and Technology (IRTA), 17121 Monells, Spain; (D.S.R.); (A.V.); (A.X.); (A.V.-P.)
| | - Aida Xercavins
- Animal Welfare Program, Institute of Agrifood Research and Technology (IRTA), 17121 Monells, Spain; (D.S.R.); (A.V.); (A.X.); (A.V.-P.)
| | - Aranzazu Varvaró-Porter
- Animal Welfare Program, Institute of Agrifood Research and Technology (IRTA), 17121 Monells, Spain; (D.S.R.); (A.V.); (A.X.); (A.V.-P.)
| | - Troy John Gibson
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield AL9 7TA, UK;
| | - Virginie Michel
- Direction of Strategy and Programmes, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 14 Rue Pierre et Marie Curie, 94701 Maisons-Alfort, France;
| | - Alexandra Contreras-Jodar
- Animal Welfare Program, Institute of Agrifood Research and Technology (IRTA), 17121 Monells, Spain; (D.S.R.); (A.V.); (A.X.); (A.V.-P.)
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Mirra A, Hight D, Kovacevic A, Levionnois OL. Sedline ® Miscalculation of Depth of Anaesthesia Variables in Two Pigs Due to Electrocardiographic Signal Contamination. Animals (Basel) 2023; 13:2699. [PMID: 37684963 PMCID: PMC10487201 DOI: 10.3390/ani13172699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/10/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
Two young (11-week-old) pigs underwent sole propofol anaesthesia as part of an experimental study. The depth of anaesthesia was evaluated both clinically and using the electroencephalography(EEG)-based monitor Sedline; in particular, the patient state index, suppression ratio, raw EEG traces, and its spectrogram were assessed. Physiological parameters and electrocardiographic activity were continuously monitored. In one pig (Case 1), during the administration of high doses of propofol, the Sedline-generated variables suddenly indicated an increased EEG activity while this was not confirmed by observation of either the raw EEG or its spectrogram. In the second pig (Case 2), a similar event was recorded during euthanasia with systemic pentobarbital. Both events happened while the EEG activity was isoelectric except for signal interferences and synchronous in rhythm and shape with the electrocardiographic activity. The suggestion of increased brain activity based on the interpretation of the Sedline variables was suspected wrong; most probably due to electrocardiographic interferences. In pigs, the patient state index and suppression ratio, as calculated by the Sedline monitor, could be influenced by the electrocardiographic activity contaminating the EEG trace, especially during otherwise isoelectric periods (strong EEG depression). Visual interpretation of the raw EEG and of the spectrogram remains necessary to identify such artefacts.
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Affiliation(s)
- Alessandro Mirra
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland;
| | - Darren Hight
- Department of Anaesthesiology and Pain Medicine, Inselspital Bern University Hospital, University of Bern, 3010 Bern, Switzerland;
| | - Alan Kovacevic
- Small Animal Internal Medicine, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland;
| | - Olivier Louis Levionnois
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland;
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Rucinque DS, van de Vis H, Reimert H, Roth B, Foss A, Taconeli CA, Gerritzen M. Pre-Slaughter Stunning of Farmed Atlantic Halibut in CO 2-Saturated Seawater: Assessment of Unconsciousness by Electroencephalography (EEG). Animals (Basel) 2023; 13:1993. [PMID: 37370503 DOI: 10.3390/ani13121993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/25/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
As fish welfare becomes a growing concern, it is important to ensure humane treatment during slaughter. This study aimed to assess the onset of unconsciousness in Atlantic halibut immersed in CO2-saturated seawater through electroencephalography (EEG). Of the 29 fish studied, 10 exhibited escape attempts, indicating aversion to CO2-saturated water despite its oxygenation. EEG signals showed four distinct phases: transitional, excitation (high amplitude-high frequency), suppressed, and iso-electric phases. The onset of the suppressed phase, indicative of unconsciousness, occurred on average 258.8 ± 46.2 s after immersion. The spectral analysis of the EEG signals showed a progressive decrease in median frequency, spectral edge frequency, and high frequency contribution, which corresponded to the gradual loss of consciousness. The study concludes that CO2-saturated water is not recommended for pre-slaughter handling of halibut due to the extended time required for the onset of unconsciousness and the observed aversive behaviour. Ensuring humane treatment during slaughter is important for addressing public concern and safeguarding fish welfare in all stages of production.
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Affiliation(s)
- Daniel Santiago Rucinque
- Faculdade de Zootecnia e Engenharia de Alimentos, Laboratório de Aquicultura, Universidade de São Paulo, Av. Duque de Caxias Norte 222, São Paulo 13635-900, Brazil
| | - Hans van de Vis
- Wageningen Livestock Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - Henny Reimert
- Wageningen Livestock Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - Bjørn Roth
- Department of Processing Technology, Nofima, 4068 Stavanger, Norway
| | - Atle Foss
- Akvaplan-niva, Fram Centre, 9296 Tromsø, Norway
| | | | - Marien Gerritzen
- Wageningen Livestock Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands
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Mirra A, Gamez Maidanskaia E, Carmo LP, Levionnois O, Spadavecchia C. How is depth of anaesthesia assessed in experimental pigs? A scoping review. PLoS One 2023; 18:e0283511. [PMID: 36952576 PMCID: PMC10035875 DOI: 10.1371/journal.pone.0283511] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/09/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND Despite the large number of pigs involved in translational studies, no gold standard depth of anaesthesia indicators are available. We undertook a scoping review to investigate and summarize the evidence that sustains or contradicts the use of depth of anaesthesia indicators in this species. METHODS Medline, Embase and CAB abstract were searched up to September 22nd 2022. No limits were set for time, language and study type. Only original articles of in vivo studies using pigs or minipigs undergoing general anaesthesia were included. The depth of anaesthesia indicators reported in the selected papers were divided in two categories: A, indicators purposely investigated as method to assess depth of anaesthesia; B, indicators reported but not investigated as method to assess depth of anaesthesia. RESULTS Out of 13792 papers found, 105 were included after the screening process. Category A: 17 depth of anaesthesia indicators were found in 19 papers. Studies were conducted using inhalant anaesthetics as the main anaesthetic agent in the majority of the cases (13/19 = 68.4%), while 3/19 (15.8%) used propofol. The most investigated depth of anaesthesia indicators were bispectral index (8/19 = 42.1%) and spectral edge frequency 95% (5/19 = 26.3%). Contrasting results about the specific usefulness of each depth of anaesthesia indicators were reported. Category B: 23 depth of anaesthesia indicators were found in 92 papers. The most reported depth of anaesthesia indicators were: motor response following a stimulus (37/92 = 40.2%), depth of anaesthesia scores (21/92 = 23.3%), bispectral index (16/92 = 17.8%) and spectral edge frequency 95% (9/92 = 9.8%). CONCLUSION Results highlight the lack of scientifically valid and reliable indicators to ensure adequate depth of anaesthesia in pigs.
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Affiliation(s)
- Alessandro Mirra
- Anaesthesiology and Pain Therapy Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Ekaterina Gamez Maidanskaia
- Anaesthesiology and Pain Therapy Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Luís Pedro Carmo
- Department of Clinical Research und Public Health (DCR-VPH), Vetsuisse Faculty, Veterinary Public Health Institute, University of Bern, Bern, Switzerland
- Norwegian Veterinary Institute, Ås, Norway
| | - Olivier Levionnois
- Anaesthesiology and Pain Therapy Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Claudia Spadavecchia
- Anaesthesiology and Pain Therapy Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Mirra A, Spadavecchia C, Levionnois O. Correlation of Sedline-generated variables and clinical signs with anaesthetic depth in experimental pigs receiving propofol. PLoS One 2022; 17:e0275484. [PMID: 36174080 PMCID: PMC9522294 DOI: 10.1371/journal.pone.0275484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/16/2022] [Indexed: 11/19/2022] Open
Abstract
Most of currently available electroencephalographic (EEG)-based tools to assess depth of anaesthesia have not been studied or have been judged unreliable in pigs. Our primary aim was to investigate the dose-effect relationship between increasing propofol dose and variables generated by the EEG-based depth of anaesthesia monitor Sedline in pigs. A secondary aim was to compare the anaesthetic doses with clinical outcomes commonly used to assess depth of anaesthesia in this species. Sixteen juvenile pigs were included. Propofol infusion was administered at 10 mg kg-1 h-1, increased by 10 mg kg-1 h-1 every 15 minutes, and stopped when an EEG Suppression ratio >80% was reached. Patient state index, suppression ratio, left and right spectral edge frequency 95%, and outcomes from commonly used clinical methods to assess depth of anaesthesia in pigs were recorded. The best pharmacodynamic model was assessed for Patient state index, suppression ratio, left and right spectral edge frequency 95% in response to propofol administration. The decrease of Patient state index best fitted to an inhibitory double-sigmoid model (including a plateau phase). The increase of suppression ratio fitted a typical sigmoid Emax model. No relevant relationship could be identified between spectral edge frequency 95% values and propofol administration. A large variability in clinical outcomes was observed among pigs, such that they did not provide a reliable evaluation of propofol dose. The relationship between propofol dose and Patient state index/suppression ratio described in the present study can be used for prediction in future investigations. The evaluation of depth of anaesthesia based on common clinical outcomes was not reliable.
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Affiliation(s)
- Alessandro Mirra
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
- * E-mail:
| | - Claudia Spadavecchia
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Olivier Levionnois
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Saenubol P, Akatvipat A, Pleumsamran A, Chankrachang S. Correlation between bispectral index value and modified Glasgow Coma Scale score in dogs with altered level of consciousness. J Vet Emerg Crit Care (San Antonio) 2020; 31:52-58. [PMID: 33135305 DOI: 10.1111/vec.13014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 03/29/2019] [Accepted: 05/02/2019] [Indexed: 11/26/2022]
Abstract
OBJECTIVE This study aims to identify the correlation between bispectral index (BIS) value and modified Glasgow Coma Scale (MGCS) score in dogs with altered level of consciousness (ALOC). DESIGN This prospective, observational, clinical study was conducted from February 2016 to March 2017, and follow-up was conducted until the death of dogs or their discharge from the hospital. SETTING This study was performed at the Small Animal Teaching Hospital. ANIMALS A total of 31 client-owned dogs (males, 20; females, 11) with ALOC and MGCS score <18 with no restrictions for age, breed, sex, and body weight were included. Dogs that received neuromuscular blocking agents before MGCS score evaluation were excluded. INTERVENTIONS BIS values were measured using the Covidien BIS Loc 2 Channel OEM module and a pediatric 4 sensor with a bifrontal application pattern. MEASUREMENTS AND MAIN RESULTS Minimal databases of initial neurological assessment, blood profiles, and chest and skull radiographs were developed. In addition, MGCS scores and BIS values were recorded. The mean BIS values for mild, moderate, and severe brain injuries were 89.14 ± 6.52, 77.21 ± 9.82, and 50.58 ± 27.04, respectively. Correlation analysis revealed a significantly positive relationship between BIS values and MGCS scores (r = 0.75; P < 0.001). CONCLUSIONS The significant correlation observed between MGCS scores and BIS values in dogs with ALOC demonstrated the usefulness of BIS as an alternative to MGCS for monitoring consciousness in patients with ALOC caused by traumatic brain injury, encephalitis, etc.
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Affiliation(s)
- Phitchaya Saenubol
- Master's Degree Program in Veterinary Science, Faculty of Veterinary Medicine, Chiang Mai University, Muang, Chiang Mai, Thailand
| | - Areerath Akatvipat
- Department of Companion Animals and Wildlife Clinic, Faculty of Veterinary Medicine, Chiang Mai University, Muang, Chiang Mai, Thailand
| | - Apisate Pleumsamran
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Muang, Chiang Mai, Thailand
| | - Siwaporn Chankrachang
- Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Muang, Chiang Mai, Thailand
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Bradbury AG, Clutton RE. Are neuromuscular blocking agents being misused in laboratory pigs? Br J Anaesth 2016; 116:476-85. [PMID: 26934943 DOI: 10.1093/bja/aew019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The literature (2012-4) describing experimental pig surgery was reviewed to estimate the extent to which neuromuscular block (NMB) is used, to examine methods for ensuring unconsciousness, and to identify the rationale for use of NMB and establish the anaesthetist's training. In the first stage of a two-stage review, NMB use was estimated using Web of Knowledge to identify articles describing NMB during pig surgeries. In the second stage, PubMed and Google Scholar were used to increase the number of articles for determining measures taken to prevent accidental awareness during general anaesthesia (AAGA). The corresponding authors of screened articles were emailed four times to establish the reason for using NMB and the anaesthetists' backgrounds (medical, veterinary, or technical). The first search revealed NMB use in 80 of 411 (20%) studies. Of the 153 articles analysed in the second stage, two described strategies to reduce AAGA. Some (6%) papers did not provide information on anaesthetic doses; citations supporting anaesthetic efficacy were found in only 13. Five of 69 papers using inhalation agents measured end-tidal anaesthetic concentrations based on human, not porcine, minimal alveolar concentrations. The methods in 13% of articles reporting anaesthetic depth assessment were incomplete or questionable, or both; four described using somatic motor reflexes. Corresponding authors of 121 articles reported that the principal reason for NMB was improved 'surgical visualization' (26%). Medical or veterinary anaesthetists supervised anaesthesia in 70% of studies; non-anaesthetists provided NMB, unsupervised, in 23. Nine respondents prioritized experimental expediency over pig welfare. In laboratory pig studies, AAGA may be prevalent; reported details of its attempted prevention are woefully inadequate.
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Affiliation(s)
- A G Bradbury
- Wellcome Trust Critical Care Laboratory for Large Animals, Roslin Institute & Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Roslin, Midlothian EH25 9RG, UK
| | - R E Clutton
- Wellcome Trust Critical Care Laboratory for Large Animals, Roslin Institute & Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Roslin, Midlothian EH25 9RG, UK
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Verhoeven MTW, Gerritzen MA, Kluivers-Poodt M, Hellebrekers LJ, Kemp B. Validation of behavioural indicators used to assess unconsciousness in sheep. Res Vet Sci 2015; 101:144-53. [PMID: 26267105 DOI: 10.1016/j.rvsc.2015.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 06/07/2015] [Accepted: 06/14/2015] [Indexed: 10/23/2022]
Abstract
The validity of behavioural indicators to assess unconsciousness under different slaughter conditions is under (inter)national debate. The aim of this study was to validate eyelid-, withdrawal-, threat reflex and rhythmic breathing as indicators to assess unconsciousness in sheep. Sheep were monitored during repeated propofol anaesthesia (n=12) and during non-stunned slaughter (n=22). Changes in the EEG and behavioural indices of consciousness/unconsciousness were assessed and compared in sheep. Threat reflex and rhythmic breathing correlated with EEG activity during propofol anaesthesia whilst absence of non-rhythmic breathing or threat reflex indicated unconsciousness. None of the behavioural indicators correlated with EEG activity during non-stunned slaughter. Absence of regular breathing and eyelid reflex was observed 00:27±00:12 min and 00:59±00:17 min (mean±SD) respectively after animals were considered unconscious, indicating that absence of regular breathing and eyelid reflex are distinctly conservative indicators of unconsciousness during non-stunned slaughter in sheep.
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Affiliation(s)
- M T W Verhoeven
- Wageningen University and Research Centre, Livestock Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands; Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
| | - M A Gerritzen
- Wageningen University and Research Centre, Livestock Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - M Kluivers-Poodt
- Wageningen University and Research Centre, Livestock Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - L J Hellebrekers
- Wageningen University and Research Centre, Central Veterinary Institute, P.O. Box 65, 8200AB Lelystad, The Netherlands
| | - B Kemp
- Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands
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Effects of acute bleeding followed by hydroxyethyl starch 130/0.4 or a crystalloid on propofol concentrations, cerebral oxygenation, and electroencephalographic and haemodynamic variables in pigs. Vet Med Int 2014; 2014:710394. [PMID: 24971192 PMCID: PMC4055214 DOI: 10.1155/2014/710394] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/31/2014] [Accepted: 04/14/2014] [Indexed: 11/18/2022] Open
Abstract
Bleeding changes the haemodynamics, compromising organ perfusion. In this study, the effects of bleeding followed by replacement with hydroxyethyl starch 130/0.4 (HES) or lactated Ringer's (LR) on cerebral oxygenation and electroencephalogram-derived parameters were investigated. Twelve young pigs under propofol-remifentanil anaesthesia were bled 30 mL/kg and, after a 20-minute waiting period, volume replacement was performed with HES (GHES; N = 6) or LR (GRL; N = 6). Bleeding caused a decrease of more than 50% in mean arterial pressure (P < 0.01) and a decrease in cerebral oximetry (P = 0.039), bispectral index, and electroencephalogram total power (P = 0.04 and P < 0.01, resp.), while propofol plasma concentrations increased (P < 0.01). Both solutions restored the haemodynamics and cerebral oxygenation similarly and were accompanied by an increase in electroencephalogram total power. No differences between groups were found. However, one hour after the end of the volume replacement, the cardiac output (P = 0.03) and the cerebral oxygenation (P = 0.008) decreased in the GLR and were significantly lower than in GHES (P = 0.02). Volume replacement with HES 130/0.4 was capable of maintaining the cardiac output and cerebral oxygenation during a longer period than LR and caused a decrease in the propofol plasma concentrations.
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Sandercock DA, Auckburally A, Flaherty D, Sandilands V, McKeegan DEF. Avian reflex and electroencephalogram responses in different states of consciousness. Physiol Behav 2014; 133:252-9. [PMID: 24878315 DOI: 10.1016/j.physbeh.2014.05.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 05/07/2014] [Indexed: 11/30/2022]
Abstract
Defining states of clinical consciousness in animals is important in veterinary anaesthesia and in studies of euthanasia and welfare assessment at slaughter. The aim of this study was to validate readily observable reflex responses in relation to different conscious states, as confirmed by EEG analysis, in two species of birds under laboratory conditions (35-week-old layer hens (n=12) and 11-week-old turkeys (n=10)). We evaluated clinical reflexes and characterised electroencephalograph (EEG) activity (as a measure of brain function) using spectral analyses in four different clinical states of consciousness: conscious (fully awake), semi-conscious (sedated), unconscious-optimal (general anaesthesia), unconscious-sub optimal (deep hypnotic state), as well as assessment immediately following euthanasia. Jaw or neck muscle tone was the most reliable reflex measure distinguishing between conscious and unconscious states. Pupillary reflex was consistently observed until respiratory arrest. Nictitating membrane reflex persisted for a short time (<1 min) after respiratory arrest and brain death (isoelectric EEG). The results confirm that the nictitating membrane reflex is a conservative measure of death in poultry. Using spectral analyses of the EEG waveforms it was possible to readily distinguish between the different states of clinical consciousness. In all cases, when birds progressed from a conscious to unconscious state; total spectral power (PTOT) significantly increased, whereas median (F50) and spectral edge (F95) frequencies significantly decreased. This study demonstrates that EEG analysis can differentiate between clinical states (and loss of brain function at death) in birds and provides a unique integration of reflex responses and EEG activity.
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Affiliation(s)
- Dale A Sandercock
- Animal and Veterinary Science Research Group, Scotland's Rural College (SRUC), West Mains Road, Edinburgh EH16 4SA, UK
| | | | - Derek Flaherty
- School of Veterinary Medicine, University of Glasgow, UK
| | - Victoria Sandilands
- Avian Science Research Centre, Scotland's Rural College, Auchincruive Ayr KA6 5HW, UK
| | - Dorothy E F McKeegan
- Institute for Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, UK.
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Silva A, Venâncio C, Ortiz AL, Souza AP, Amorim P, Ferreira DA. The effect of high doses of remifentanil in brain near-infrared spectroscopy and in electroencephalographic parameters in pigs. Vet Anaesth Analg 2013; 41:153-62. [PMID: 24119044 DOI: 10.1111/vaa.12091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/20/2013] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To study the effects of a high remifentanil bolus dose on pig's electroencephalographic indices and on brain regional and global oxygenation. STUDY DESIGN Prospective experimental study. ANIMALS Twelve healthy Large-White male pigs, age 3 months and weight 26.2 ± 3.6 kg. METHODS Anaesthesia was induced with intravenous propofol 4 mg kg⁻¹, then maintained with constant rate infusions of propofol (15 mg kg⁻¹ hour⁻¹) and remifentanil (0.3 μg kg⁻¹ minute⁻¹). Following instrumentation, all pigs received a 5 μg kg⁻¹ remifentanil bolus. The responses of jugular venous oxygen saturation, cardiac output and cerebral oxygen saturation to the remifentanil bolus were studied. The Bispectral index, spectral edge frequency 95%, total power, approximate entropy and permutation entropy were also studied. Repeated measures anova and Pearson correlation were used to analyze the effect of remifentanil bolus on these variables until 5 minutes after the bolus. RESULTS Cardiac output and cerebral oxygen saturation decreased significantly after the remifentanil bolus from 4.6 ± 0.9 to 3.8 ± 1.0 L minute⁻¹ and from 65 ± 6 to 62 ± 1% (p < 0.05), respectively. No significant changes were observed in the jugular venous oxygen saturation (p > 0.05) nor in any of the electroencephalogram derived indices (p > 0.05). Correlation analysis revealed strong positive significant correlations between cerebral oxygen saturation and cardiac output (r = 0.82, p < 0.001) and between cerebral oxygen saturation and approximate entropy (r = 0.65, p < 0.001). CONCLUSIONS AND CLINICAL RELEVANCE The effect caused by the remifentanil bolus on the brain oxygenation seems to be better reflected by the cerebral oxygen saturation than the jugular venous oxygen saturation. The effect of remifentanil on the electroencephalogram may not be reflected in indices derived from the electroencephalogram, but the potential of the approximate entropy in reflecting changes caused by opioids on the electroencephalogram should be further investigated.
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Affiliation(s)
- Aura Silva
- Toxicology, REQUIMTE, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
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McKeegan D, Sandercock D, Gerritzen M. Physiological responses to low atmospheric pressure stunning and the implications for welfare. Poult Sci 2013; 92:858-68. [DOI: 10.3382/ps.2012-02749] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Baars JH, Rintisch U, Rehberg B, Lahrmann KH, von Dincklage F. Prediction of motor responses to surgical stimuli during bilateral orchiectomy of pigs using nociceptive flexion reflexes and the bispectral index derived from the electroencephalogram. Vet J 2013; 195:377-81. [DOI: 10.1016/j.tvjl.2012.07.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 07/08/2012] [Accepted: 07/10/2012] [Indexed: 10/27/2022]
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Influence of progressive hemorrhage and subsequent cardiopulmonary resuscitation on the bispectral index during isoflurane anesthesia in a swine model. J Trauma Acute Care Surg 2012; 72:1614-9. [PMID: 22695430 DOI: 10.1097/ta.0b013e3182569e9c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The bispectral index for measurement of anesthetic depth may be modified by extreme hypotension during hemorrhagic shock. In this study, the influence of progressive hemorrhage and subsequent cardiopulmonary resuscitation on the bispectral index was investigated under controlled anesthetic depth. METHODS Fifteen swine were anesthetized through inhalation of isoflurane under bispectral index monitoring. Hemorrhagic shock was induced using a stepwise hemorrhage model in which 20%, 10%, and 10% of estimated blood volume were removed over three 30-minute periods and then 5% was removed every 30 minutes until the mean arterial pressure was less than 10 mm Hg. After reaching this criterion, chest compression with 0.2-mg/kg epinephrine and hydroxyethyl starch infusion was performed for 20 minutes or until the mean arterial pressure exceeded 50 mm Hg. The pharmacodynamics of the isoflurane effect was examined before hemorrhage, after 40% bleeding, and after resuscitation. RESULTS A mean (SD) volume of 836 (78) mL of blood was drained before resuscitation. The bispectral index suddenly decreased at a mean (SD) arterial pressure of 22 (3) mm Hg and showed isoelectric activity in most animals before resuscitation. Eight pigs were resuscitated, and the bispectral index recovered during a range of periods after recovery of the mean arterial pressure. The pharmacodynamic effect of isoflurane did not change after 40% bleeding but increased after resuscitation, with the alteration correlated with the time for resuscitation. CONCLUSION In hemorrhagic shock, the bispectral index merely reflects the anesthetic depth until development of lethal hypotension at which brain electrical activity cannot be sustained. After recovery from depression, the potency of isoflurane can increase depending on the cerebral hypoperfusion time. The increased bispectral index for anesthetics after resuscitation might reflect the degree of cerebral damage due to hypoperfusion.
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Silva A, Antunes L. Electroencephalogram-based anaesthetic depth monitoring in laboratory animals. Lab Anim 2012; 46:85-94. [PMID: 22517991 DOI: 10.1258/la.2012.011135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Objective measurements of physiological parameters controlled by the autonomic nervous system such as blood pressure, heart rate and respiration are easily obtained nowadays during anaesthesia by the use of monitors: oscillometers, pulseoximeters, electrocardiograms and capnographs are available for laboratory animals. However, the effect-site of hypnotic drugs that cause general anaesthesia is the central nervous system (the brain). In the present, the adjustment of hypnotic drugs in veterinary anaesthesia is performed according to subjective evaluation of clinical signs which are not direct reflexes of anaesthetic effects on the brain, making depth of anaesthesia (DoA) assessment a complicated task. The difficulties in assessing the real anaesthetic state of a laboratory animal may not only result in welfare-threatening situations, such as awareness and pain sensation during surgery, but also in a lack of standardization of experimental conditions, as it is not easy to keep all animals from an experiment in the same DoA without a measure of anaesthetic effect. A direct measure of this dose-effect relationship, although highly necessary, is still missing in the veterinary market. Meanwhile, research has been intense in this subject and methods based on the brain electrical activity (electroencephalogram) have been explored in laboratory animal species. The objective of this review is to explain the achievements made in this topic and clarify how far we are from an objective measure of DoA for animals.
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Affiliation(s)
- Aura Silva
- REQUIMTE, Faculdade de Farmácia da Universidade do Porto, Rua de Jorge Viterbo Ferreira No. 228, 4050-313 Porto, Portugal.
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Ribeiro LM, Ferreira DA, Brás S, Gonzalo-Orden JM, Antunes LM. Correlation between clinical signs of depth of anaesthesia and cerebral state index responses in dogs with different target-controlled infusions of propofol. Vet Anaesth Analg 2012; 39:21-8. [DOI: 10.1111/j.1467-2995.2011.00657.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Llonch P, Andaluz A, Rodríguez P, Dalmau A, Jensen EW, Manteca X, Velarde A. Assessment of consciousness during propofol anaesthesia in pigs. Vet Rec 2011; 169:496a. [PMID: 21949060 DOI: 10.1136/vr.d5643] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- P Llonch
- IRTA, Animal Welfare Subprogram, Finca Camps i Armet, Monells, 17121, Girona, Spain
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Ambrisko TD, Johnson CB, Chambers P. Effect of alfaxalone infusion on the electroencephalogram of dogs anaesthetized with halothane. Vet Anaesth Analg 2011; 38:529-35. [PMID: 21988807 DOI: 10.1111/j.1467-2995.2011.00650.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To describe the effects of alfaxalone on the canine electroencephalogram (EEG). STUDY DESIGN Experimental study. ANIMALS Eight healthy adult Huntaway dogs. METHODS Anaesthesia was induced with propofol and maintained with halothane (0.85-0.95 end-tidal volume %) in oxygen. Animals were ventilated to maintain stable end-tidal CO(2) and halothane concentrations. Following a 30 minute stabilisation period, alfaxalone (0.5 mg kg(-1) ) was infused intravenously over a 5 minute period. The electroencephalogram was recorded from the beginning of the stabilisation period until 60 minutes following the start of alfaxalone treatment. Data were subjected to fast Fourier transformation, and median frequency, 95% spectral edge frequency and total EEG power were calculated. Two-factorial repeated measures anova (time and EEG channels were factors) was used for statistical analysis (p < 0.05). RESULTS A shift in the dominant frequency band from beta to delta after alfaxalone treatment and occasional burst suppression were observed. Median frequency decreased significantly below baseline (9.2 ± 1.4 Hz) (mean ± SD) during alfaxalone infusion. The lowest value (4.8 ± 1.2 Hz) was recorded 5 minutes after the start of infusion. Spectral edge frequency also decreased below baseline (26.2 ± 1.5 Hz) and the lowest value (22.6 ± 1.5 Hz) also was detected at 5 minutes after the start of infusion. Total EEG power did not change significantly. In some frequencies EEG power increased soon after the start of alfaxalone infusion, then decreased below baseline later (biphasic pattern). CONCLUSIONS AND CLINICAL RELEVANCE Alfaxalone induced biphasic changes on EEG and decreased F(50) and F(95) in halothane anaesthetized dogs.
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Affiliation(s)
- Tamas D Ambrisko
- Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Palmerston North, New Zealand.
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Cavus E, Meybohm P, Doerges V, Hoecker J, Betz M, Hanss R, Steinfath M, Bein B. Effects of cerebral hypoperfusion on bispectral index: A randomised, controlled animal experiment during haemorrhagic shock. Resuscitation 2010; 81:1183-9. [DOI: 10.1016/j.resuscitation.2010.05.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 04/25/2010] [Accepted: 05/26/2010] [Indexed: 10/19/2022]
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Correlation between clinical signs of depth of anaesthesia and cerebral state index responses in dogs during induction of anaesthesia with propofol. Res Vet Sci 2009; 87:287-91. [DOI: 10.1016/j.rvsc.2009.02.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 01/06/2009] [Accepted: 02/10/2009] [Indexed: 11/19/2022]
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Kurita T, Takata K, Morita K, Morishima Y, Uraoka M, Katoh T, Sato S. The Influence of Hemorrhagic Shock on the Electroencephalographic and Immobilizing Effects of Propofol in a Swine Model. Anesth Analg 2009; 109:398-404. [DOI: 10.1213/ane.0b013e3181a96f9a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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BRÁS S, BRESSAN N, RIBEIRO L, FERREIRA DA, ANTUNES L, NUNES CS. A step towards effect-site target-controlled infusion with propofol in dogs: ake0for propofol. J Vet Pharmacol Ther 2009; 32:182-8. [DOI: 10.1111/j.1365-2885.2008.01019.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Martin-Jurado O, Vogt R, Kutter APN, Bettschart-Wolfensberger R, Hatt JM. Effect of inhalation of isoflurane at end-tidal concentrations greater than, equal to, and less than the minimum anesthetic concentration on bispectral index in chickens. Am J Vet Res 2008; 69:1254-61. [PMID: 18828679 DOI: 10.2460/ajvr.69.10.1254] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effect of inhalation of isoflurane at end-tidal concentrations greater than, equal to, and less than the minimum anesthetic concentration (MAC) on bispectral index (BIS) in chickens. Animals-10 chickens. PROCEDURES For each chicken, the individual MAC of isoflurane was determined by use of the toe-pinch method. After a 1-week interval, chickens were anesthetized with isoflurane at concentrations 1.75, 1.50, 1.25, 1.00, and 0.75 times their individual MAC (administered from higher to lower concentrations). At each MAC multiple, a toe pinch was performed and BIS was assessed and correlated with heart rate, blood pressure, and an awareness score (derived by use of a visual analogue scale). RESULTS Among the chickens, mean +/- SD MAC of isoflurane was 1.15 +/- 0.20%. Burst suppression was detected at every MAC multiple. The BIS and awareness score were correlated directly with each other and changed inversely with increasing isoflurane concentration. Median (range) BIS values during anesthesia at 1.75, 1.50, 1.25, 1.00, and 0.75 MAC of isoflurane were 25 (15 to 35), 35 (25 to 45), 35 (20 to 50), 40 (25 to 55), and 50 (35 to 65), respectively. Median BIS value at extubation was 70 +/- 9. Values of BIS correlated with blood pressure, but not with heart rate. Blood pressure changed with end-tidal isoflurane concentrations, whereas heart rate did not. CONCLUSIONS AND CLINICAL RELEVANCE Assessment of BIS can be used to monitor the electrical activity of the brain and the degree of unconsciousness in chickens during isoflurane anesthesia.
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Affiliation(s)
- Olga Martin-Jurado
- Clinic of Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstr 260, 8057 Switzerland
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Ribeiro LM, Ferreira DA, Bressan NM, Nunes CS, Amorim P, Antunes LM. Brain monitoring in dogs using the cerebral state index during the induction of anaesthesia via target-controlled infusion of propofol. Res Vet Sci 2007; 85:227-32. [PMID: 18061223 DOI: 10.1016/j.rvsc.2007.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 10/15/2007] [Accepted: 10/19/2007] [Indexed: 11/16/2022]
Abstract
The aim of this study was to evaluate the correlation between the cerebral state index (CSI) and the estimated propofol plasma concentrations in dogs during induction of anaesthesia. Fifteen healthy dogs undergoing scheduled routine surgical procedures were enrolled in this study. Target controlled infusion (TCI) software, based on the pharmacokinetic model for propofol, was used to control the syringe pump and to estimate plasma propofol concentrations (PropCp) and the CSI values every five-seconds. Three electrodes placed in the centre of the forehead, on the left side of the forehead and on the left mastoid were used to collect the electroencephalographic (EEG) signal converted by the cerebral state monitor into the CSI. The cerebral electrical changes induced by increasing propofol concentrations appear to be detected by CSI monitoring in dogs. The negative correlation between CSI and PropCp demonstrates that the CSI could be used to assess electrical brain activity in dogs during the induction of anaesthesia with propofol.
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