Effects of intravenous terbutaline on heart rate, arterial pressure and blood gases in anesthetized horses breathing air.
Abstract: To investigate the effects of intravenous (IV) administration of terbutaline on PaO, PaCO, pH, heart rate (HR) and arterial pressures in healthy, laterally recumbent horses breathing ambient air under total intravenous anesthesia (TIVA). Methods: Prospective experimental study. Methods: Eight healthy adult horses were enrolled. Six horses, four mares and two geldings weighing 433-624 kg, completed the study. Methods: Horses were sedated with xylazine (1.0 mg kg) IV for placement of arterial and venous catheters. Anesthesia was induced with midazolam (0.1 mg kg) and ketamine (2.2 mg kg) IV and maintained with an IV infusion of guaifenesin (50 mg mL), ketamine (2 mg mL) and xylazine (0.5 mg mL) at 1.9 ± 0.3 mL kg hour. Horses were in left lateral recumbency and breathed air spontaneously. Arterial blood was collected for pH and blood gas analysis during xylazine sedation, 15 minutes after induction of anesthesia, immediately before and 5, 15 and 30 minutes after administration of terbutaline (2 μg kg), and when the horse was standing after recovery from anesthesia. HR, systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were recorded at 5 minute intervals during anesthesia. Normal data were analyzed with anova and non-normal data were analyzed with a Friedman test with a p < 0.05 considered significant. Results: The mean PaO decreased from baseline to <60 mmHg (8.0 kPa) during anesthesia (p < 0.0001) and did not improve after administration of terbutaline. After terbutaline administration, HR increased (p = 0.002), and SAP, MAP and DAP decreased (p < 0.001) with the greatest changes occurring immediately after terbutaline administration. Conclusions: Terbutaline (2 μg kg) IV did not improve PaO and was associated with adverse cardiovascular effects during TIVA in healthy, laterally recumbent horses breathing air.
Copyright © 2016 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.
Publication Date: 2017-02-23 PubMed ID: 27125331DOI: 10.1111/vaa.12377Google Scholar: Lookup
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Summary
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This research study investigates the effects of using terbutaline, a bronchodilator, by IV on heart rate, blood gases and arterial pressure in anesthetized horses. Findings suggest that while being anesthetized and under the influence of terbutaline, horses experienced decreases in blood oxygen levels, heightened heart rate and reduced arterial pressure.
Research Methodology
In this prospective experimental study:
- Eight healthy adult horses, including four mares and two geldings, were included in the examination, out of which six completed the research.
- For the placement of arterial and venous catheters, horses were sedated with xylazine. Afterwards, two more drugs – midazolam and ketamine – are used to induce anesthesia.
- Anesthesia was maintained through an IV infusion of guaifenesin, ketamine, and xylazine. The animals remained in left lateral recumbency, breathing air spontaneously throughout the procedure.
- Arterial blood samples were collected for pH and blood gas analysis during several stages: during the sedation period, 15 minutes post-anesthesia induction, immediately pre and post-administration of terbutaline (at 5, 15 and 30 minutes), and once the horse was fully recovered from anesthesia.
- Heart rates and arterial pressures (systolic, mean, and diastolic) were recorded at 5-minute intervals during the anesthesia period.
- Various statistical analyses were performed to interpret the data.
Research Findings
Based on the research:
- Findings indicate that the mean PaO, which represents the partial pressure of oxygen in arterial blood, consistently decreased from the baseline to less than 60mmHg (8.0 kPa) throughout anesthesia. This decrease was statistically significant (p < 0.0001).
- The administration of terbutaline did not improve this reduced PaO level.
- Post administration of terbutaline, a significant increase in heart rate was observed (p = 0.002).
- Along with increased heart rate, systolic, mean, and diastolic arterial pressures were observed to decrease, indicating a substantial drop in blood pressure. These changes were greatest just after the administration of terbutaline, and were statistically significant (p < 0.001).
Research Conclusions
The study concluded that intravenous administration of terbutaline did not improve the oxygen levels in blood during anesthesia. Additionally, it was associated with negative cardiovascular effects, manifesting as an increased heart rate and a decrease in systemic arterial pressure in laterally recumbent, anesthetized horses. As such, care ought to be taken in the use of terbutaline in similar clinical situations.
Cite This Article
APA
Arcaro I, Fischer BL, Lascola KM, Clark-Price SC.
(2017).
Effects of intravenous terbutaline on heart rate, arterial pressure and blood gases in anesthetized horses breathing air.
Vet Anaesth Analg, 44(1), 70-76.
https://doi.org/10.1111/vaa.12377 Publication
Researcher Affiliations
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA.
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA. Electronic address: bfischer@illinois.edu.
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA.
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA.
MeSH Terms
- Adrenergic beta-2 Receptor Agonists / administration & dosage
- Adrenergic beta-2 Receptor Agonists / pharmacology
- Anesthesia / veterinary
- Animals
- Arterial Pressure / drug effects
- Blood Pressure
- Carbon Dioxide / blood
- Female
- Heart Rate / drug effects
- Horses
- Ketamine
- Male
- Midazolam
- Muscle Relaxants, Central
- Oxygen / blood
- Partial Pressure
- Prospective Studies
- Terbutaline / administration & dosage
- Terbutaline / pharmacology
- Xylazine
Citations
This article has been cited 2 times.- Parlar A, Arslan SO. CB2 Agonist (AM1241) Improving Effect on Ovalbumin-Induced Asthma in Rats. Iran J Pharm Res 2020 Winter;19(1):3-17.
- Mittal R, Debs LH, Patel AP, Nguyen D, Patel K, O'Connor G, Grati M, Mittal J, Yan D, Eshraghi AA, Deo SK, Daunert S, Liu XZ. Neurotransmitters: The Critical Modulators Regulating Gut-Brain Axis. J Cell Physiol 2017 Sep;232(9):2359-2372.
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