The cardiovascular status of isoflurane-anaesthetized horses with and without dexmedetomidine constant rate infusion evaluated at equivalent depths of anaesthesia.
Abstract: To compare cardiac index and oxygen extraction at equivalent depths of anaesthesia between isoflurane-anaesthetized horses and horses anesthetized with isoflurane and dexmedetomidine CRI. Methods: Sequential, blinded, randomized, balanced, crossover study. Methods: Eight horses weighing a mean ± standard deviation of 478 ± 58 kg. Methods: Horses were premedicated with 0.03 mg kg(-1) acepromazine intramuscularly (IM) and 8 μg kg(-1) dexmedetomidine intravenously (IV). Anaesthesia was induced with 2.5 mg kg(-1) ketamine and 0.1 mg kg(-1) midazolam IV and maintained with isoflurane in oxygen and air. Horses were mechanically ventilated. Fractional concentration of end-tidal isoflurane (Fe'Iso) was stabilized at 1.7% with a CRI of 0.9% NaCl (IsoNaCl), or at 1.1% with 1.75 μg kg(-1) hour(-1) dexmedetomidine (IsoDex). Mean arterial blood pressure was maintained above 60 mmHg by dobutamine infusion. Following nociceptive electrical stimulation, Fe'Iso was stabilized at a 0.1% lower concentration and nociceptive stimulation was repeated. This procedure was continued until the horse moved. Fe'Iso values prior to the concentration at which movement occurred were considered to indicate equivalent depths of anaesthesia between treatments. Cardiac index and oxygen extraction were compared at equivalent depths of anaesthesia using a paired Student's t-test. Results: Cardiac index differed between IsoNaCl at 61 ± 12 mL kg(-1) minute(-1) and IsoDex at 48 ± 10 mL kg(-1) minute(-1) (p = 0.047). In addition, oxygen extraction differed between IsoNaCl at 3.4 ± 0.8 mL kg(-1) minute(-1) and IsoDex at 4.5 ± 0.5 mL kg(-1) minute(-1) (p = 0.0042). Two horses receiving IsoNaCl were administered dobutamine at equivalent depths of anaesthesia (7.0 and 28.8 μg kg(-1) hour(-1) , respectively). Conclusions: Cardiovascular function in horses receiving isoflurane and 1.75 μg kg(-1) minute(-1) dexmedetomidine is more compromised than in horses receiving a higher concentration of isoflurane and 0.9% NaCl CRI.
© 2015 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.
Publication Date: 2015-10-21 PubMed ID: 26488527DOI: 10.1111/vaa.12315Google Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
Summary
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The study investigates the effect of isoflurane anaesthesia alone versus isoflurane alongside dexmedetomidine on the cardiovascular status of horses. The findings suggest a more compromised cardiovascular function in horses receiving the combined isoflurane-dexmedetomidine anaesthesia as compared to those receiving isoflurane alone.
Study Design and Methods
- The subject of study was a population of eight horses of mean weight 478 ± 58 kg.
- The horses were pre-medicated with acepromazine (intramuscularly) and dexmedetomidine (intravenously) prior to inducing anaesthesia with ketamine and midazolam.
- The maintenance of anaesthesia was achieved through isoflurane provided in oxygen and air, while the horses were mechanically ventilated.
- The anaesthesia protocols compared in this study were isoflurane in combination with 0.9% Sodium Chloride Continuous Rate Infusion (IsoNaCl), and isoflurane along with 1.75 μg kg(-1) hour(-1) dexmedetomidine (IsoDex).
- An electrical stimulation was applied to the horses and adjustments were made to the anaesthetic concentration until movement was perceived. The captured isoflurane concentrations were then used to gauge the equivalent depths of anaesthesia for comparison.
Results of the Study
- There was a difference in the Cardiac index between IsoNaCl (61 ± 12 mL kg(-1) minute(-1)) and IsoDex (48 ± 10 mL kg(-1) minute(-1)), with a p-value of 0.047.
- Oxygen extraction varied as well between IsoNaCl (3.4 ± 0.8 mL kg(-1) minute(-1)) and IsoDex (4.5 ± 0.5 mL kg(-1) minute(-1)), having a p-value of 0.0042.
- In two instances, horses under the IsoNaCl treatment required the administration of dobutamine to maintain mean arterial blood pressure above 60 mmHg at equivalent depths of anaesthesia.
Conclusions
- It was concluded that horses anaesthetized with a combination of isoflurane and dexmedetomidine showed more compromised cardiovascular function compared to those anaesthetized with a higher concentration of isoflurane and Sodium Chloride Continuous Rate Infusion.
Cite This Article
APA
Risberg ÅI, Ranheim B, Krontveit RI, Lervik A, Haga HA.
(2015).
The cardiovascular status of isoflurane-anaesthetized horses with and without dexmedetomidine constant rate infusion evaluated at equivalent depths of anaesthesia.
Vet Anaesth Analg, 43(4), 412-423.
https://doi.org/10.1111/vaa.12315 Publication
Researcher Affiliations
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
- Centre for Epidemiology and Biostatistics, Faculty of Veterinary Medicine and Life Sciences, Norwegian University of Life Sciences, Oslo, Norway.
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
MeSH Terms
- Acepromazine / administration & dosage
- Analgesics, Non-Narcotic / administration & dosage
- Anesthesia / methods
- Anesthesia / veterinary
- Anesthesia Recovery Period
- Anesthetics, Inhalation
- Animals
- Arterial Pressure / drug effects
- Cardiovascular Physiological Phenomena / drug effects
- Cardiovascular System / drug effects
- Cross-Over Studies
- Dexmedetomidine / administration & dosage
- Dopamine Antagonists / administration & dosage
- Horses
- Isoflurane
- Ketamine
- Midazolam
- Pain Measurement / methods
- Pain Measurement / veterinary
- Preanesthetic Medication / veterinary
Citations
This article has been cited 5 times.- Hoeberg E, Haga HA, Lervik A. Cardiovascular effects of intravenous morphine in anesthetized horse.. Front Vet Sci 2022;9:1007345.
- Abass M, Ibrahim H, Salci H, Hamed MA. Evaluation of the effect of different sedative doses of dexmedetomidine on the intestinal motility in clinically healthy donkeys (Equus asinus).. BMC Vet Res 2022 Jul 14;18(1):274.
- Zhang J, Sun X, Cheng W, Ren W. Application of Different Doses of Dexmedetomidine Combined with General Anesthesia in Anesthesia of Patients with Traumatic Tibiofibular Fractures and Its Effect on the Incidence of Adverse Reactions.. J Healthc Eng 2021;2021:3080098.
- Gozalo-Marcilla M, Ringer SK. Recovery after General Anaesthesia in Adult Horses: A Structured Summary of the Literature.. Animals (Basel) 2021 Jun 14;11(6).
- Hopster K, Wittenberg-Voges L, Kästner SBR. Xylazine infusion in isoflurane-anesthetized and ventilated healthy horses: Effects on cardiovascular parameters and intestinal perfusion.. Can J Vet Res 2017 Oct;81(4):249-254.
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