Effects of dobutamine on cardiovascular function and respiratory gas exchange after enoximone in isoflurane-anaesthetized ponies.
Abstract: To evaluate the combined effects of enoximone and dobutamine on the cardiovascular system and respiratory gas exchange in isoflurane-anaesthetized ponies. Methods: Prospective, randomized, experimental study. Methods: Six ponies (286 +/- 52 kg), aged 5.0 +/- 1.6 years. Methods: After sedation (romifidine 80 microg kg(-1)), anaesthesia was induced with midazolam (0.06 mg kg(-1)) and ketamine (2.2 mg kg(-1)) and maintained with isoflurane in oxygen. The ponies were ventilated to maintain eucapnia. After 90 minutes (=T0), enoximone alone (0.5 mg kg(-1)) (E) or enoximone, followed by a constant rate infusion of dobutamine (0.5 microg kg(-1) minute(-1)) (ED) for 120 minutes, was administered. Each pony received both treatments in a crossover trial, with at least 2 weeks between treatments. Heart rate (HR), cardiac output (CO), stroke volume (SV), right atrial (RAP), systolic (SAP), diastolic (DAP) and mean arterial pressure (MAP), blood gases, systemic vascular resistance (SVR), oxygen delivery (DO(2)) and several respiratory gas exchange variables were measured before treatment and until T120. Statistical analysis was based on a mixed model with treatment, time and their interaction as fixed categorical effects, pony as random effect, comparing treatments globally (alpha = 0.05) and at specific timepoints (Bonferroni-adjusted alpha = 0.00625). Results: Compared to enoximone alone, ED treatment produced an increase in HR, CO, SV, RAP, SAP, DAP, MAP, packed cell volume (PCV) and DO(2). The difference was significant from T60 to T120 (except at T80) for HR, throughout the observational period for CO, SAP, MAP, PCV and DO(2), from T40 to T120 for DAP, at T10,T60,T80 and T120 for SV and at T10 and T20 for RAP. Overall decreases occurred in SVR and dead space ventilation (V(D)/V(T)). V(D)/V(T) was lower at T20 and from T80 to T120. Venous oxygen saturation was increased from T60 onwards. Conclusions: The results suggest that enoximone and dobutamine have additive cardiovascular effects and reduce V(D)/V(T) in isoflurane-anaesthetized ponies.
Publication Date: 2009-06-16 PubMed ID: 19522889DOI: 10.1111/j.1467-2995.2007.00392.xGoogle Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
Summary
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This research studies the combined impacts of two drugs, enoximone and dobutamine, on the heart, blood flow, and breathing in ponies under isoflurane anesthesia. It found that, compared to enoximone alone, adding dobutamine resulted in improved cardiovascular function, oxygen delivery, and reduced dead space ventilation (unproductive breathing).
Research Context and Methods
- The study was an experimental attempt to understand the combined impact of the drugs enoximone and dobutamine on the cardiovascular system and respiratory gas exchange in ponies. This research was conducted as a prospective, randomized study.
- Six ponies, each weighing approximately 286 kg and aged about 5 years, were part of the experiment.
- The ponies were first sedated then anesthetized with isoflurane in oxygen and were maintained under this condition with assistance in ventilation.
- After anatomical stability was confirmed at 90 minutes into anaesthesia (=T0), the ponies were administered either the drug enoximone alone or enoximone followed by a constant infusion of dobutamine for a period of 120 minutes. Each pony received both treatments in a crossover trial with at least a 2-week break between treatments.
- Throughout the experiment, key parameters – heart rate, cardiac output, stroke volume, right atrial pressure, systolic, diastolic, and mean arterial pressure, blood gases, systemic vascular resistance, oxygen delivery, and several respiratory gas exchange variables were all measured to assess the effects of the administered drugs.
Research Findings
- The result showed that the combined treatment of enoximone and dobutamine significantly improved several cardiovascular parameters as compared to enoximone alone. This included an increase in heart rate, cardiac output, stroke volume, right atrial, systolic, diastolic, mean arterial pressures, packed cell volume and oxygen delivery.
- Statistically significant results were observed at different time points throughout the observational period.
- Additionally, the combined administration also resulted in an overall decrease in systemic vascular resistance and dead space ventilation (unproductive breathing where no gas exchange takes place).
- The treatment also led to increased venous oxygen saturation from 60 minutes onwards.
Conclusion
- This research suggests that the combined usage of enoximone and dobutamine have additive effects on cardiovascular parameters and also in reducing unproductive ventilation in ponies under isoflurane anaesthesia.
- These findings could have implications for medical procedures involving ponies, potentially improving their cardiovascular function and minimizing respiratory issues during anaesthesia.
Cite This Article
APA
Schauvliege S, Van den Eede A, Duchateau L, Gasthuys F.
(2009).
Effects of dobutamine on cardiovascular function and respiratory gas exchange after enoximone in isoflurane-anaesthetized ponies.
Vet Anaesth Analg, 35(4), 306-318.
https://doi.org/10.1111/j.1467-2995.2007.00392.x Publication
Researcher Affiliations
- Department of Surgery and Anaesthesia of Domestic Animals, Faculty of Veterinary Medicine, University of Ghent, Salisburylaan 133, Merelbeke, Belgium. stijn.schauvliege@ugent.be
MeSH Terms
- Anesthetics, Combined / pharmacology
- Anesthetics, Inhalation / administration & dosage
- Animals
- Blood Pressure / drug effects
- Carbon Dioxide / blood
- Cardiac Output / drug effects
- Cardiotonic Agents / pharmacology
- Cross-Over Studies
- Dobutamine / pharmacology
- Enoximone / pharmacology
- Female
- Heart Rate / drug effects
- Horses / physiology
- Isoflurane / administration & dosage
- Male
- Oxygen / blood
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