Comparison of the effects of caffeine and doxapram on respiratory and cardiovascular function in foals with induced respiratory acidosis.
Abstract: To determine and compare the effects of caffeine and doxapram on cardiorespiratory variables in foals during isoflurane-induced respiratory acidosis. Methods: 6 clinically normal foals (1 to 3 days old). Methods: At intervals of > or = 24 hours, foals received each of 3 IV treatments while in a steady state of hypercapnia induced by isoflurane anesthesia (mean +/- SD, 1.4 +/- 0.3% endtidal isoflurane concentration). After assessment of baseline cardiorespiratory variables, a low dose of the treatment was administered and variables were reassessed; a high dose was then administered, and variables were again assessed. Sequential low- and high-dose treatments included doxapram (loading dose of 0.5 mg/kg, followed by a 20-minute infusion at 0.03 mg/kg/min and then 0.08 mg/kg/min), caffeine (5 mg/kg and 10 mg/kg), and saline (0.9% NaCl) solution (equivalent volumes). Results: Administration of doxapram at both infusion rates resulted in a significant increase in respiratory rate, minute ventilation, arterial blood pH, PaO(2), and arterial blood pressure. These variables were also significantly higher during doxapram administration than during caffeine or saline solution administration. There was a significant dose-dependent decrease in PaCO(2) and arterial bicarbonate concentration during doxapram treatment. In contrast, PaCO(2) increased from baseline values after administration of saline solution or caffeine. The PaCO(2) value was significantly lower during doxapram treatment than it was during caffeine or saline solution treatment. Conclusions: Results indicated that doxapram restored ventilation in a dose-dependent manner in neonatal foals with isoflurane-induced hypercapnia. The effects of caffeine on respiratory function were indistinguishable from those of saline solution.
Publication Date: 2007-12-07 PubMed ID: 18052748DOI: 10.2460/ajvr.68.12.1407Google Scholar: Lookup
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- Controlled Clinical Trial
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study investigates and compares the impact of caffeine and doxapram on the cardiorespiratory functions in foals (young horses) during a state of respiratory acidosis induced by isoflurane. The findings demonstrate that doxapram effectively improved ventilation in the foals in a dose-dependent manner, with its effects markedly more significant than those seen after administering caffeine or saline solution.
Study Methods
- The study involved six clinically normal foals aged between one to three days.
- The foals were subjected to a state of hypercapnia (excess carbon dioxide in the bloodstream), induced by isoflurane anesthesia. Equivalent doses of doxapram, caffeine, and saline solution were respectively administered to the foals at intervals of more or equal to 24 hours.
- Following the administration of a low dose of each treatment, cardiorespiratory variables were reassessed. Subsequently, a high dose was administered, and the variables were again evaluated.
Results
- Doxapram use led to a significant increase in respiratory rate, minute ventilation, arterial blood pH, PaO2 (partial pressure of oxygen), and arterial blood pressure in the foals. These variables were significantly higher during doxapram use than when caffeine or saline solution was administered.
- During doxapram treatment, there was a noteworthy decrease in PaCO2 (partial pressure of carbon dioxide) and arterial bicarbonate concentration, indicative of improved respiratory function.
- After administering saline solution or caffeine, PaCO2 surged from baseline values. However, the PaCO2 readings were considerably lower during doxapram treatment than during caffeine or saline solution administration.
Conclusions
- The research suggests that doxapram restores ventilation in neonatal foals experiencing isoflurane-induced hypercapnia, and its effect is dose-dependent.
- On the other hand, caffeine’s effects on respiratory function seemed to be indistinguishable from those observed after administering saline solution.
Cite This Article
APA
Giguère S, Sanchez LC, Shih A, Szabo NJ, Womble AY, Robertson SA.
(2007).
Comparison of the effects of caffeine and doxapram on respiratory and cardiovascular function in foals with induced respiratory acidosis.
Am J Vet Res, 68(12), 1407-1416.
https://doi.org/10.2460/ajvr.68.12.1407 Publication
Researcher Affiliations
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0136, USA.
MeSH Terms
- Acidosis, Respiratory / chemically induced
- Acidosis, Respiratory / drug therapy
- Acidosis, Respiratory / veterinary
- Anesthetics, Inhalation / adverse effects
- Animals
- Caffeine / therapeutic use
- Central Nervous System Stimulants / therapeutic use
- Dose-Response Relationship, Drug
- Doxapram / therapeutic use
- Horses
- Isoflurane / adverse effects
Citations
This article has been cited 5 times.- Gomez DE, Biermann NM, Sanchez LC. Physicochemical Approach to Determine the Mechanism for Acid-Base Disorders in 793 Hospitalized Foals. J Vet Intern Med 2015 Sep-Oct;29(5):1395-402.
- Vengust M. Hypercapnic respiratory acidosis: a protective or harmful strategy for critically ill newborn foals?. Can J Vet Res 2012 Oct;76(4):275-80.
- Mendonça JC, Pereira KHNP, Xavier GM, Fuchs KDM, Faustino TG, Codognoto VM, Tsunemi MH, Takahira RK, Apparício M, Lourenço MLG. Comparative Effects of Aminophylline, Caffeine, and Doxapram in Hypoxic Neonatal Dogs Born by Cesarean Section. Animals (Basel) 2025 Dec 3;15(23).
- Boller M, Burkitt-Creedon JM, Byers CG, Fletcher DJ, Farrell KS, Davidson AP, Fricke S, Bassu G, Grundy SA, Lopate C, Veronesi MC. RECOVER Guidelines: Newborn Resuscitation in Dogs and Cats. Evidence and Knowledge Gap Analysis With Treatment Recommendations. J Vet Emerg Crit Care (San Antonio) 2025 Aug;35 Suppl 1(Suppl 1):3-59.
- Boller M, Burkitt-Creedon JM, Fletcher DJ, Byers CG, Davidson AP, Farrell KS, Bassu G, Fausak ED, Grundy SA, Lopate C, Veronesi MC. RECOVER Guidelines: Newborn Resuscitation in Dogs and Cats. Clinical Guidelines. J Vet Emerg Crit Care (San Antonio) 2025 Aug;35 Suppl 1(Suppl 1):S60-S85.
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