Effects of dopamine, dobutamine, dopexamine, phenylephrine, and saline solution on intramuscular blood flow and other cardiopulmonary variables in halothane-anesthetized ponies.
Abstract: To evaluate the effect on intramuscular blood flow (IMBF) and hemodynamic variables of 4 antihypotensive agents given during anesthesia. Methods: 8 ponies. Methods: Halothane-anesthetized ponies (n = 6) positioned in lateral recumbency received, on separate occasions, infusions of each of the following 4 agents in serially increasing dosages or saline solution: phenylephrine hydrochloride (0.25, 0.5, 1, and 2 microg/kg of body weight), dopamine (2.5, 5, 10, and 20 microg/kg), dobutamine (1, 2.5, 5, and 10 microg/kg), and dopexamine (0.5, 1, 5, and 10 microg/kg). Changes in IMBF (by laser-Doppler flowmetry) in nondependent and dependent triceps brachii muscles and cardiopulmonary variables were measured. Results: Phenylephrine at all dosages failed to improve IMBF or cardiac index (CI), but increased mean arterial pressure (MAP) and systemic vascular resistance (SVR); 2 ponies had forelimb lameness on recovery. Dopamine (10 microg/kg/min) increased CI, MAP, and IMBF in the dependent muscle. A higher dose (20 microg/kg/min) caused cardiac arrhythmias and muscular tremor. Dobutamine increased Cl, MAP, and IMBF of both forelimbs, effects being significant for 2.5 microg/kg/min, with further improvement as the dosage increased. In 2 ponies, 10 microg of dobutamine/kg/min caused cardiac arrhythmias. Dopexamine (1 and 5 microg/kg/min) increased CI, MAP, and IMBF in the nondependent muscle, and 10 microg/kg/min caused muscular tremor, sweating, and arrhythmias. SVR was reduced after infusion of dopamine, dobutamine, or dopexamine. Conclusions: During anesthesia of equids, an increase in Cl and MAP is necessary to improve IMBF in the dependent forelimb. Conclusions: Of the agents investigated, dobutamine proved the most consistent in improving IMBF.
Publication Date: 1998-11-26 PubMed ID: 9829408
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The given research investigates the impact of various antihypotensive agents on intramuscular blood flow and other cardiovascular parameters in ponies under anesthesia, concluding that dobutamine consistently improves intramuscular blood flow most effectively.
Methodology
- The study was conducted on six halothane-anesthetized ponies, each pony was treated with the different suggested antihypotensive agents in various dosages during separate incidents. These agents are phenylephrine hydrochloride, dopamine, dobutamine, and dopexamine.
Results
- Phenylephrine, at all tested dosages, did not enhance intramuscular blood flow or the cardiac index but did increase mean arterial pressure and systemic vascular resistance. Some treated ponies showed lameness in the forelimb upon recovery.
- Dopamine elevated cardiac index, mean arterial pressure, and intramuscular blood flow in the dependent muscle at the dosage of 10 microg/kg/min. However, a higher dosage of 20 microg/kg/min resulted in cardiac irregularities and muscle tremors.
- Dobutamine was observed to increase cardiac index, mean arterial pressure, and intramuscular blood flow in both forelimbs, with significant changes being observed at a dosage of 2.5 microg/kg/min. Elevated results were seen as the dosage increased, yet, in two ponies, a high dosage of dobutamine resulted in cardiac irregularities.
- Dopexamine elevated cardiac index, mean arterial pressure, and intramuscular blood flow in the non-dependent muscle at doses of 1 and 5 microg/kg/min, but a high dose led to muscle tremors, sweating and arrhythmias.
- Systemic vascular resistance decreased after the infusion of dopamine, dobutamine or dopexamine.
Conclusions
- The results indicated that during the anesthesia of these equids, an increase in cardiac index and mean arterial pressure is necessary to enhance the intramuscular blood flow in the dependent forelimb.
- Dobutamine was identified as the most consistent agent in improving intramuscular blood flow among the tested medications.
Cite This Article
APA
Lee YH, Clarke KW, Alibhai HI, Song D.
(1998).
Effects of dopamine, dobutamine, dopexamine, phenylephrine, and saline solution on intramuscular blood flow and other cardiopulmonary variables in halothane-anesthetized ponies.
Am J Vet Res, 59(11), 1463-1472.
Publication
Researcher Affiliations
- Department of Farm Animal and Equine Medicine and Surgery, Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom.
MeSH Terms
- Anesthetics, Inhalation
- Animals
- Blood Pressure / drug effects
- Cardiac Output / drug effects
- Cardiotonic Agents / pharmacology
- Cardiovascular System / drug effects
- Dobutamine / pharmacology
- Dopamine / analogs & derivatives
- Dopamine / pharmacology
- Drug Evaluation / veterinary
- Female
- Forelimb / blood supply
- Forelimb / drug effects
- Halothane
- Horses / physiology
- Lameness, Animal / chemically induced
- Laser-Doppler Flowmetry / veterinary
- Male
- Muscle, Skeletal / blood supply
- Muscle, Skeletal / drug effects
- Phenylephrine / pharmacology
- Regional Blood Flow / drug effects
- Sodium Chloride / pharmacology
- Vascular Resistance / drug effects
- Vasodilator Agents / pharmacology
Citations
This article has been cited 7 times.- Rabbogliatti V, Amari M, Brioschi FA, Di Cesare F, Zani DD, De Zani D, Di Giancamillo M, Cagnardi P, Ravasio G. Use of dexmedetomidine repeated subcutaneous administration for balanced anaesthesia in horses. BMC Vet Res 2022 Jul 11;18(1):269.
- Tucker L, Almeida D, Wendt-Hornickle E, Baldo CF, Allweiler S, Guedes AGP. Effect of 15° Reverse Trendelenburg Position on Arterial Oxygen Tension during Isoflurane Anesthesia in Horses. Animals (Basel) 2022 Feb 1;12(3).
- 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.
- 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).
- 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.
- Won YJ, Shin YS, Lee KY, Cho WY. The effect of phenylephrine on the onset time of rocuronium. Korean J Anesthesiol 2010 Oct;59(4):244-8.
- 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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