Hemodynamic responses in halothane-anesthetized horses given infusions of dopamine or dobutamine.
Abstract: The hemodynamic changes induced by constant infusions of dopamine or dobutamine (each 3, 5, and 10 micrograms/kg/min) were observed in halothane-anesthetized horses. Left ventricular dp/dt and cardiac output were increased in horses given dobutamine at dosage of 3 micrograms/kg/min and in those given either of the drugs at dosages of 5 and 10 micrograms/kg/min. Concomitant increases in systemic arterial blood pressure occurred at lower infusion dosage rates of dobutamine than those of dopamine and were modulated by dosage-related changes in peripheral vascular resistance that were different between the 2 drugs. Total peripheral vascular resistance was unchanged by the 3 micrograms/kg/min dosage of dopamine, significantly (P less than 0.05) decreased at the 5 micrograms/kg/min dosage of dopamine, and returned to base line in horses when given the largest dosage. Dobutamine had no effect on total peripheral vascular resistance. Heart rate was significantly (P less than 0.05) decreased by the 2 smaller dosages of dobutamine, but returned to base line at the 10 micrograms/kg/min dosage. Heart rates did not change significantly in response to dopamine over the range of the dosages. Sinus tachycardia with atrioventricular conduction block was noted in some horses given either of the drugs. The results of the present study indicate that the hemodynamic responses in horses given dopamine or dobutamine infusions are similar to those in other species, and are the net result of the different adrenergic pharmacologic profiles of the 2 drugs combined with autonomic nervous system reflexes.
Publication Date: 1985-02-01 PubMed ID: 3994103
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- Journal Article
Summary
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The research observes the hemodynamic changes in halothane-anesthetized horses when given infusions of dopamine or dobutamine at varying dosage levels. The findings suggest that the responses are influenced by the pharmacologic profiles of the two drugs in combination with nervous system reflexes.
Study Overview
- The study investigated how constant infusions of dopamine or dobutamine (at dosages of 3, 5, and 10 micrograms/kg/min) affect hemodynamic changes in halothane-anesthetized horses.
- Parameters observed included hemodynamics such as left ventricular dp/dt, cardiac output, blood pressure, peripheral vascular resistance, and heart rates.
Key Findings
- Dopamine and dobutamine increased the left ventricular dp/dt and cardiac output in horses with different effectiveness at different dosage levels.
- The increase in systemic arterial blood pressure occurred at lower infusion dosages of dobutamine than dopamine.
- Each of these drugs influenced peripheral vascular resistance in different ways. For instance, dopamine didn’t affect total peripheral vascular resistance at the lowest dosage, significantly decreased it at the medium dosage, and had it return to normal at the highest dosage. Dobutamine, on the other hand, had no effect on total peripheral vascular resistance.
- The heart rate significantly decreased at the low and medium dosages of dobutamine but returned to normal at the highest dosage. Dopamine infusions didn’t significantly affect the heart rate.
Implications and Conclusion
- The study revealed some incidence of sinus tachycardia with atrioventricular conduction block in some horses provided with either of the drugs.
- The findings suggest that the hemodynamic responses in horses given dopamine or dobutamine infusions are similar to those in other species. These responses are believed to be the net result of the different adrenergic pharmacologic profiles of the two drugs combined with autonomic nervous system reflexes.
Cite This Article
APA
Swanson CR, Muir WW, Bednarski RM, Skarda RT, Hubbell JA.
(1985).
Hemodynamic responses in halothane-anesthetized horses given infusions of dopamine or dobutamine.
Am J Vet Res, 46(2), 365-370.
Publication
Researcher Affiliations
MeSH Terms
- Anesthesia, General / veterinary
- Animals
- Blood Pressure / drug effects
- Cardiac Output / drug effects
- Catecholamines / pharmacology
- Dobutamine / pharmacology
- Dopamine / pharmacology
- Electrocardiography / veterinary
- Female
- Halothane
- Heart Rate / drug effects
- Hemodynamics / drug effects
- Horses / physiology
- Horses / surgery
- Male
Citations
This article has been cited 5 times.- Garcia Filho SG, de Andrade FSRM, Dos Santos RST, Gonçalves LA, Pereira MAA, de Souza AF, Ambrósio AM, Fantoni DT. Comparison of Hemodynamic Effects of Dobutamine and Ephedrine Infusions in Isoflurane-Anesthetized Horses. Vet Sci 2023 Apr 6;10(4).
- Ryan A, Gurney M, Steinbacher R. Suspected vagal reflex and hyperkalaemia inducing asystole in an anaesthetised horse. Equine Vet J 2022 Sep;54(5):927-933.
- Ohta M, Kurimoto S, Ishikawa Y, Tokushige H, Mae N, Nagata S, Mamada M. Cardiovascular effects of dobutamine and phenylephrine infusion in sevoflurane-anesthetized Thoroughbred horses. J Vet Med Sci 2013 Nov;75(11):1443-8.
- Dyson DH, Pascoe PJ, McDonell WN. Effects of intravenously administered glycopyrrolate in anesthetized horses. Can Vet J 1999 Jan;40(1):29-32.
- Gorenberg EB, Slack J, Stefanovski D, Theiss D, Hopster K. Dobutamine improves haemodynamics and oxygen delivery in standing and isoflurane-anaesthetised horses. Equine Vet J 2025 Nov;57(6):1677-1689.
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