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Journal of veterinary internal medicine2015; 29(2); 663-672; doi: 10.1111/jvim.12570

Cerebral and brainstem electrophysiologic activity during euthanasia with pentobarbital sodium in horses.

Abstract: An overdose of pentobarbital sodium administered i.v. is the most commonly used method of euthanasia in veterinary medicine. Determining death after the infusion relies on the observation of physical variables. However, it is unknown when cortical electrical activity and brainstem function are lost in a sequence of events before death. Objective: To examine changes in the electrical activity of the cerebral cortex and brainstem during an overdose of pentobarbital sodium solution for euthanasia. Our testing hypothesis is that isoelectric pattern of the brain in support of brain death occurs before absence of electrocardiogram (ECG) activity. Methods: Fifteen horses requiring euthanasia. Methods: Prospective observational study. Horses with neurologic, orthopedic, and cardiac illnesses were selected and instrumented for recording of electroencephalogram, electrooculogram, brainstem auditory evoked response (BAER), and ECG. Physical and neurologic (brainstem reflexes) variables were monitored. Results: Loss of cortical electrical activity occurred during or within 52 seconds after the infusion of euthanasia solution. Cessation of brainstem function as evidenced by a lack of brainstem reflexes and disappearance of the BAER happened subsequently. Despite undetectable heart sounds, palpable arterial pulse, and mean arterial pressure, recordable ECG was the last variable to be lost after the infusion (5.5-16 minutes after end of the infusion). Conclusions: Overdose of pentobarbital sodium solution administered i.v. is an effective, fast, and humane method of euthanasia. Brain death occurs within 73-261 seconds of the infusion. Although absence of ECG activity takes longer to occur, brain death has already occurred.
Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
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Publication Date: 2015-03-19 PubMed ID: 25800436PubMed Central: PMC4895516DOI: 10.1111/jvim.12570Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research paper studies the sequence of the loss of electrical activity in the brain and the heart during euthanasia of horses performed using pentobarbital sodium solution. It demonstrates that brain death occurs first, followed by the cessation of electrocardiogram (ECG) activity.

Objective and Hypothesis

The objective of this exploratory study was to understand the sequence of organ shutdown when an overdose of pentobarbital sodium solution is given intravenously for euthanasia. The researchers hypothesized that brain death, marked by an isoelectric pattern in the brain, may occur before the cessation of ECG activity.

Methods

  • The observational study involved the euthanasia of 15 horses suffering from neurological, orthopedic, and cardiac conditions.
  • Using various medical instruments, the scientists recorded electroencephalogram, electrooculogram, brainstem auditory evoked response (BAER), and ECG data during the administration of euthanasia solution.
  • Along with these electronic variables, they observed and noted physical variables like brainstem reflexes.

Results

  • The results showed that the loss of cortical electrical activity happened during or within 52 seconds of the infusion of the euthanasia solution.
  • The cessation of brainstem function followed this, marked by the lack of brainstem reflexes, and the disappearance of BAER.
  • Despite the heart sounds becoming undetectable, the arterial pulse disappearing, and the mean arterial pressure dropping, ECG remained the last electronic variable to be lost, between 5.5 to 16 minutes after the end of the infusion.

Conclusions

In conclusion, administering an overdose of pentobarbital sodium solution was found to be a quick, effective, and humane method of euthanasia. The research concluded that brain death, an important marker of overall death, happened within 73 to 261 seconds of the infusion. The absence of ECG activity, although delayed, confirmed the occurrence of brain death.

Cite This Article

APA
Aleman M, Williams DC, Guedes A, Madigan JE. (2015). Cerebral and brainstem electrophysiologic activity during euthanasia with pentobarbital sodium in horses. J Vet Intern Med, 29(2), 663-672. https://doi.org/10.1111/jvim.12570

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 29
Issue: 2
Pages: 663-672

Researcher Affiliations

Aleman, M
  • Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616.
Williams, D C
    Guedes, A
      Madigan, J E

        MeSH Terms

        • Animals
        • Blood Pressure
        • Brain Stem / drug effects
        • Brain Stem / physiology
        • Cerebrum / drug effects
        • Cerebrum / physiology
        • Electroencephalography / veterinary
        • Euthanasia, Animal / methods
        • Female
        • Horses / physiology
        • Hypnotics and Sedatives / administration & dosage
        • Hypnotics and Sedatives / pharmacology
        • Male
        • Pentobarbital / administration & dosage
        • Pentobarbital / pharmacology

        References

        This article includes 27 references
        1. . AVMA Guidelines for the euthanasia of animals: 2013 Edition.. J Am Vet Med Assoc 2013;1–102.
        2. Welschehold S, Boor S, Reuland K, Thömke F, Kerz T, Reuland A, Beyer C, Gartenschläger M, Wagner W, Giese A, Müller-Forell W. Technical aids in the diagnosis of brain death: a comparison of SEP, AEP, EEG, TCD and CT angiography.. Dtsch Arztebl Int 2012 Sep;109(39):624-30.
          pmc: PMC3475291pubmed: 23093994doi: 10.3238/arztebl.2012.0624google scholar: lookup
        3. McKeegan DE, Reimert HG, Hindle VA, Boulcott P, Sparrey JM, Wathes CM, Demmers TG, Gerritzen MA. Physiological and behavioral responses of poultry exposed to gas-filled high expansion foam.. Poult Sci 2013 May;92(5):1145-54.
          pubmed: 23571322doi: 10.3382/ps.2012-02587google scholar: lookup
        4. Kongara K, McIlhone AE, Kells NJ, Johnson CB. Electroencephalographic evaluation of decapitation of the anaesthetized rat.. Lab Anim 2014 Jan;48(1):15-9.
          pubmed: 24367032doi: 10.1177/0023677213502016google scholar: lookup
        5. Baumans V, Meijer JC, Haberham ZL, de Groot HN, Hellebrekers LJ. [Euthanasia of piglets: gas or injection?].. Tijdschr Diergeneeskd 1998 Dec 15;123(24):738-42.
          pubmed: 9879622
        6. Hellebrekers LJ, Baumans V, Bertens AP, Hartman W. On the use of T61 for euthanasia of domestic and laboratory animals; an ethical evaluation.. Lab Anim 1990 Jul;24(3):200-4.
          pubmed: 2395317doi: 10.1258/002367790780866254google scholar: lookup
        7. Chalifoux A, Dallaire A. Physiologic and behavioral evaluation of CO euthanasia of adult dogs.. Am J Vet Res 1983 Dec;44(12):2412-7.
          pubmed: 6686419
        8. Lalonde-Robert V, Desgent S, Duss S, Vachon P. Electroencephalographic and physiologic changes after tricaine methanesulfonate immersion of African clawed frogs (Xenopus laevis).. J Am Assoc Lab Anim Sci 2012;51(5):622-7.
          pmc: PMC3447452pubmed: 23312092
        9. Mikeska JA, Klemm WR. EEG evaluation of humaneness of asphyxia and decapitation euthanasia of the laboratory rat.. Lab Anim Sci 1975 Apr;25(2):175-9.
          pubmed: 1169659
        10. Holson RR. Euthanasia by decapitation: evidence that this technique produces prompt, painless unconsciousness in laboratory rodents.. Neurotoxicol Teratol 1992 Jul-Aug;14(4):253-7.
          pubmed: 1522830doi: 10.1016/0892-0362(92)90004-tgoogle scholar: lookup
        11. Mayevsky A, Barbiro-Michaely E, Ligeti L, MacLaughlin AC. Effects of euthanasia on brain physiological activities monitored in real-time.. Neurol Res 2002 Oct;24(7):647-51.
          pubmed: 12392199doi: 10.1179/016164102101200690google scholar: lookup
        12. Williams DC, Aleman M, Tharp B, Fletcher DJ, Kass PH, Steffey EP, LeCouteur RA, Holliday TA. Qualitative and quantitative characteristics of the electroencephalogram in normal horses after sedation.. J Vet Intern Med 2012 May-Jun;26(3):645-53.
          pubmed: 22489924doi: 10.1111/j.1939-1676.2012.00921.xgoogle scholar: lookup
        13. Aleman M, Puchalski SM, Williams DC, Kass PH, Holliday TA. Brainstem auditory-evoked responses in horses with temporohyoid osteoarthropathy.. J Vet Intern Med 2008 Sep-Oct;22(5):1196-202.
          pubmed: 18681921doi: 10.1111/j.1939-1676.2008.0158.xgoogle scholar: lookup
        14. Short TG, Leslie K. 'Known unknowns and unknown unknowns': electroencephalographic burst suppression and mortality.. Br J Anaesth 2014 Dec;113(6):897-9.
          pubmed: 24875662doi: 10.1093/bja/aeu147google scholar: lookup
        15. Su Y, Yang Q, Liu G, Zhang Y, Ye H, Gao D, Zhang Y, Chen W. Diagnosis of brain death: confirmatory tests after clinical test.. Chin Med J (Engl) 2014;127(7):1272-7.
          pubmed: 24709179
        16. Monteiro LM, Bollen CW, van Huffelen AC, Ackerstaff RG, Jansen NJ, van Vught AJ. Transcranial Doppler ultrasonography to confirm brain death: a meta-analysis.. Intensive Care Med 2006 Dec;32(12):1937-44.
          pubmed: 17019556doi: 10.1007/s00134-006-0353-9google scholar: lookup
        17. Sloan TB. Anesthetic effects on electrophysiologic recordings.. J Clin Neurophysiol 1998 May;15(3):217-26.
          pubmed: 9681559doi: 10.1097/00004691-199805000-00005google scholar: lookup
        18. Spehlmann R. The normal BAEP. In: Spehlmann R, ed. Evoked Potential Primer. Stoneham, MA: Butterworth Publishers; 1985:204–216.
        19. Spehlmann R. Coma. In: Spehlmann R, ed. Evoked Potential Primer. Stoneham, MA: Butterworth Publishers, 1985; 217–235.
        20. Aleman M, Holliday TA, Nieto JE, Williams DC. Brainstem auditory evoked responses in an equine patient population: part I--adult horses.. J Vet Intern Med 2014 Jul-Aug;28(4):1310-7.
          pmc: PMC4857955pubmed: 24902479doi: 10.1111/jvim.12379google scholar: lookup
        21. Aleman M, Madigan JE, Williams DC, Holliday TA. Brainstem auditory evoked responses in an equine patient population. Part II: foals.. J Vet Intern Med 2014 Jul-Aug;28(4):1318-24.
          pmc: PMC4857935pubmed: 24903742doi: 10.1111/jvim.12377google scholar: lookup
        22. Stockard JJ, Stockard JE, Sharbrough FW. Nonpathological factors influencing brainstem auditory evoked potentials. Am J EEG Technol 1978;18:177.
        23. Bobbin RP, May JG, Lemoine RL. Effects of pentobaribtal and ketamine on brain stem auditory potentials. Latency and amplitude intensity functions after intraperitoneal administration.. Arch Otolaryngol 1979 Aug;105(8):467-70.
          pubmed: 464884doi: 10.1001/archotol.1979.00790200029006google scholar: lookup
        24. Sutton LN, Frewen T, Marsh R, Jaggi J, Bruce DA. The effects of deep barbiturate coma on multimodality evoked potentials.. J Neurosurg 1982 Aug;57(2):178-85.
          pubmed: 7086510doi: 10.3171/jns.1982.57.2.0178google scholar: lookup
        25. Marsh RR, Frewen TC, Sutton LN, Potsic WP. Resistance of the auditory brain stem response to high barbiturate levels.. Otolaryngol Head Neck Surg 1984 Dec;92(6):685-8.
          pubmed: 6440088doi: 10.1177/019459988409200616google scholar: lookup
        26. Stockard JJ, Sharbrough FW, Tinker JA. Effects of hypothermia on the human brainstem auditory response.. Ann Neurol 1978 Apr;3(4):368-70.
          pubmed: 666280doi: 10.1002/ana.410030416google scholar: lookup
        27. Buhl R, Andersen LO, Karlshøj M, Kanters JK. Evaluation of clinical and electrocardiographic changes during the euthanasia of horses.. Vet J 2013 Jun;196(3):483-91.
          pubmed: 23290564doi: 10.1016/j.tvjl.2012.11.016google scholar: lookup

        Citations

        This article has been cited 8 times.
        1. Raschdorf K, Mohseni A, Hogle K, Cheung A, So K, Manouchehri N, Khalili M, Lingawi S, Grunau B, Kuo C, Christenson J, Shadgan B. Evaluation of transcutaneous near-infrared spectroscopy for early detection of cardiac arrest in an animal model. Sci Rep 2023 Mar 20;13(1):4537.
          doi: 10.1038/s41598-023-31637-1pubmed: 36941315google scholar: lookup
        2. Jiranantakan T, Ritchie S, Rowe C, Tran J, McDonald C, Vazquez S, Auld R, Brown J. Retracted: Survival After Pentobarbitone Overdose Confirmed Through Prescription, Recreational and Illicit Substance Evaluation (Prise) Programme in Australia. Forensic Sci Res 2021;6(3):231-236.
          doi: 10.1080/20961790.2021.1975613pubmed: 34868716google scholar: lookup
        3. Baker-Cook BI, Moritz AL, Zwueste D, Schwean-Lardner K, Machin KL. Evaluation of intravenous T-61 as a euthanasia method for birds. Can Vet J 2021 Apr;62(4):367-373.
          pubmed: 33867548
        4. Hernandez E, James F, Torrey S, Widowski T, Schwean-Lardner K, Monteith G, Turner PV. Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium Injection. Front Vet Sci 2019;6:297.
          doi: 10.3389/fvets.2019.00297pubmed: 31552284google scholar: lookup
        5. DeNicola AJ, Miller DS, DeNicola VL, Meyer RE, Gambino JM. Assessment of humaneness using gunshot targeting the brain and cervical spine for cervid depopulation under field conditions. PLoS One 2019;14(2):e0213200.
          doi: 10.1371/journal.pone.0213200pubmed: 30818392google scholar: lookup
        6. Aleman M, Davis E, Williams DC, Madigan JE, Smith F, Guedes A. Electrophysiologic Study of a Method of Euthanasia Using Intrathecal Lidocaine Hydrochloride Administered during Intravenous Anesthesia in Horses. J Vet Intern Med 2015 Nov-Dec;29(6):1676-82.
          doi: 10.1111/jvim.13607pubmed: 26332487google scholar: lookup
        7. LeGrand JL, Ozawa SM, Silverstein-Metzler MG, Estes JM, Moiseiwitsch NA, Stephens JQ, Atkins HM, Petritz OA. Comparison of Intrarenal and Intravenous Injections of Sodium Pentobarbital for Euthanasia in New Zealand White Rabbits (Oryctolagus cuniculus). J Am Assoc Lab Anim Sci 2025 Jun 1;64(4):1-8.
          doi: 10.30802/AALAS-JAALAS-25-012pubmed: 40683629google scholar: lookup
        8. Stanger A, Buhmann G, Dörfelt S, Zablotski Y, Fischer A. Rapid hearing threshold assessment with modified auditory brainstem response protocols in dogs. Front Vet Sci 2024;11:1358410.
          doi: 10.3389/fvets.2024.1358410pubmed: 38511189google scholar: lookup
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