The effect of hyoscine on dobutamine requirement in spontaneously breathing horses anaesthetized with halothane.
Abstract: To determine whether hyoscine has a sparing effect on the volume of dobutamine required to maintain mean arterial pressure (MAP) at 70 mmHg in horses anaesthetized with halothane. Methods: Prospective, randomized, controlled clinical trial. Methods: Twenty adult horses weighing 507 +/- 97 kg (mean +/- SD), aged 10 +/- 5 years. Methods: Pre-anaesthetic medication in all horses was intramuscular (IM) acepromazine (40 mug kg(-1)) and intravenous (IV) detomidine (0.02 mg kg(-1)). Anaesthesia was induced with ketamine (2.2 mg kg(-1) IV) and diazepam (0.02 mg kg(-1) IV), and maintained with halothane in oxygen. Horses breathed spontaneously. Flunixin (1.1 mg kg(-1) IV) was given to provide analgesia. Heart rate, ECG, invasive arterial pressure, respiratory rate, percentage end-tidal carbon dioxide, percentage end-tidal halothane and partial pressure of oxygen and carbon dioxide in arterial blood and blood pH were monitored. Dobutamine was infused by an infusion pump to maintain MAP at 70 mmHg. Horses were randomly assigned to receive saline or hyoscine (0.1 mg kg(-1)) IV 30 minutes after induction. The heart rate, MAP and volume of dobutamine infused over 30-minute periods were measured and analysed statistically using a one-way anova. Results: After administration of hyoscine, heart rate increased for 10 minutes (p < 0.01) and MAP for 5 minutes (p < 0.01). There was no difference in the volume of dobutamine infused over 30 minutes between horses given hyoscine or saline, although there was a wide individual variation in dobutamine requirements. No side effects of hyoscine were seen. Conclusions: The increase in heart rate and blood pressure that occurs after 0.1 mg kg(-1) hyoscine is given IV in anaesthetized horses, is of short duration and does not significantly alter the amount of dobutamine required to maintain arterial pressure over the next 30 minutes. Clinical relevance The short duration of action of 0.1 mg kg(-1) hyoscine IV may limit its usefulness for correction of hypotension in horses anaesthetized with halothane. Further work is necessary to investigate the effects of higher or repeated doses or constant rate infusions of hyoscine.
Publication Date: 2006-04-26 PubMed ID: 16634940DOI: 10.1111/j.1467-2995.2005.00250.xGoogle Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
- Research Support
- Non-U.S. Gov't
- Acepromazine
- Adult Horses
- Analgesia
- Anesthesia
- Arterial Pressure
- Blood Pressure
- Carbon Dioxide
- Clinical Study
- Detomidine
- Diazepam
- Dobutamine
- Equine Health
- Flunixin Meglumine
- Halothane
- Heart Rate
- Horses
- Intramuscular Administration
- Intravenous Administration
- Ketamine
- Oxygen
- Random
- Respiratory Rate
- Veterinary Medicine
- Veterinary Practice
Summary
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The research paper is about a clinical trial investigating whether hyoscine affects the required amount of dobutamine needed to maintain blood pressure in horses anesthetized with halothane.
Objective and Methodology
- The underlying objective of this study was to determine whether the drug hyoscine could effectively reduce the quantity of dobutamine needed to retain mean arterial pressure (MAP) at 70 mmHg in horses anesthetized with halothane.
- This study was a prospective, randomized controlled clinical trial, thereby indicating a high level of scientific evidence.
- The trial involved twenty adult horses as subjects, with a range of different body weights and ages.
- A defined protocol was followed for inducing anaesthesia in horses which involved a combination of several drugs (acepromazine, detomidine, ketamine, diazepam, halothane) to ensure the horses were in a sedate, pain-free, and controllable state.
- Dobutamine was administered through an infusion pump to keep the blood pressure stable throughout the procedure.
- Horses were provided either saline or hyoscine, and various health parameters such as heart rate and blood pressure were closely monitored.
Results and Conclusion
- Post administering hyoscine, horses experienced a temporary increase in heart rate and blood pressure.
- However, the volume of dobutamine required to maintain arterial pressure remained unaffected irrespective of the horses given hyoscine or saline.
- It was noted that dobutamine requirements varied widely between individual horses.
- Despite its transient effects on the heart rate and blood pressure, hyoscine did not have any observable side effects.
- The researchers concluded that while hyoscine does cause an initial increase in heart rate and blood pressure, it does not have a significant effect on the volume of dobutamine required to maintain arterial pressure in the 30 minute period post-administration.
- Conversely, the short-lived action of hyoscine might limit its practical use regarding correcting low blood pressure conditions in horses anaesthetized with halothane.
Implications and Further Research
- The consequences of this study indicate that while hyoscine might cause a temporary increase in vitals, it doesn’t help in reducing the requirement of dobutamine in maintaining arterial pressure.
- This prompts a need for additional research focusing on exploring the effects of varied doses or constant rate infusions of hyoscine.
- Further studies could potentially provide better insights and might guide new methodologies to manage hypotension in anesthetized horses.
Cite This Article
APA
Borer KE, Clarke KW.
(2006).
The effect of hyoscine on dobutamine requirement in spontaneously breathing horses anaesthetized with halothane.
Vet Anaesth Analg, 33(3), 149-157.
https://doi.org/10.1111/j.1467-2995.2005.00250.x Publication
Researcher Affiliations
- Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts, UK. kborer@rvc.ac.uk
MeSH Terms
- Adjuvants, Anesthesia / administration & dosage
- Adjuvants, Anesthesia / pharmacology
- Adrenergic beta-Agonists / administration & dosage
- Adrenergic beta-Agonists / pharmacology
- Anesthesia, General / veterinary
- Anesthetics, Combined / administration & dosage
- Anesthetics, Combined / pharmacology
- Animals
- Blood Pressure / drug effects
- Dobutamine / administration & dosage
- Dobutamine / pharmacology
- Electrocardiography / drug effects
- Female
- Halothane
- Heart Rate / drug effects
- Horses / physiology
- Infusions, Intravenous / veterinary
- Male
- Muscarinic Antagonists / administration & dosage
- Muscarinic Antagonists / pharmacology
- Respiration / drug effects
- Scopolamine / administration & dosage
- Scopolamine / pharmacology
- Treatment Outcome
Citations
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