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Effects of sevoflurane dose and mode of ventilation on cardiopulmonary function and blood biochemical variables in horses

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  • 1 Department of Surgical and Radiological Science, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 2 Department of Clinical Studies, Colorado State University, Fort Collins, CO 80523.
  • | 3 California Animal Health and Food Safety Laboratory, University of California, Davis, CA 95616.
  • | 4 Present address is the Dean's office, College of Agriculture, Dept 3354, 1000 E University Ave, Laramie, WY 82071.
  • | 5 California Animal Health and Food Safety Laboratory, University of California, Davis, CA 95616.
  • | 6 Department of Surgical and Radiological Science, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 7 Present address is 6506 Ashton Ct, Granite Bay, CA 95746.

Abstract

Objective—To quantitate effects of dose of sevoflurane and mode of ventilation on cardiovascular and respiratory function in horses and identify changes in serum biochemical values associated with sevoflurane anesthesia.

Animals—6 healthy adult horses.

Procedure—Horses were anesthetized twice: first, to determine the minimum alveolar concentration (MAC) of sevoflurane and second, to characterize cardiopulmonary and serum biochemical responses of horses to 1.0, 1.5, and 1.75 MAC multiples of sevoflurane during controlled and spontaneous ventilation.

Results—Mean (± SEM) MAC of sevoflurane was 2.84 ± 0.16%. Cardiovascular performance during anesthesia decreased as sevoflurane dose increased; the magnitude of cardiovascular depression was more severe during mechanical ventilation, compared with spontaneous ventilation. Serum inorganic fluoride concentration increased to a peak of 50.8 ± 7.1 µmol/L at the end of anesthesia. Serum creatinine concentration and sorbitol dehydrogenase activity reached their greatest values (2.0 ± 0.8 mg/dL and 10.2 ± 1.8 U/L, respectively) at 1 hour after anesthesia and then returned to baseline by 1 day after anesthesia. Serum creatine kinase, aspartate aminotransferase, and alkaline phosphatase activities reached peak values by the first (ie, creatine kinase) or second (ie, aspartate aminotransferase and alkaline phosphatase) day after anesthesia.

Conclusions and Clinical Relevance—Sevoflurane causes dose-related cardiopulmonary depression, and mode of ventilation further impacts the magnitude of this depression. Except for serum inorganic fluoride concentration, quantitative alterations in serum biochemical indices of liver- and muscle-cell disruption and kidney function were considered clinically unremarkable and similar to results from comparable studies of other inhalation anesthetics. (Am J Vet Res 2005;66:606–614)

Abstract

Objective—To quantitate effects of dose of sevoflurane and mode of ventilation on cardiovascular and respiratory function in horses and identify changes in serum biochemical values associated with sevoflurane anesthesia.

Animals—6 healthy adult horses.

Procedure—Horses were anesthetized twice: first, to determine the minimum alveolar concentration (MAC) of sevoflurane and second, to characterize cardiopulmonary and serum biochemical responses of horses to 1.0, 1.5, and 1.75 MAC multiples of sevoflurane during controlled and spontaneous ventilation.

Results—Mean (± SEM) MAC of sevoflurane was 2.84 ± 0.16%. Cardiovascular performance during anesthesia decreased as sevoflurane dose increased; the magnitude of cardiovascular depression was more severe during mechanical ventilation, compared with spontaneous ventilation. Serum inorganic fluoride concentration increased to a peak of 50.8 ± 7.1 µmol/L at the end of anesthesia. Serum creatinine concentration and sorbitol dehydrogenase activity reached their greatest values (2.0 ± 0.8 mg/dL and 10.2 ± 1.8 U/L, respectively) at 1 hour after anesthesia and then returned to baseline by 1 day after anesthesia. Serum creatine kinase, aspartate aminotransferase, and alkaline phosphatase activities reached peak values by the first (ie, creatine kinase) or second (ie, aspartate aminotransferase and alkaline phosphatase) day after anesthesia.

Conclusions and Clinical Relevance—Sevoflurane causes dose-related cardiopulmonary depression, and mode of ventilation further impacts the magnitude of this depression. Except for serum inorganic fluoride concentration, quantitative alterations in serum biochemical indices of liver- and muscle-cell disruption and kidney function were considered clinically unremarkable and similar to results from comparable studies of other inhalation anesthetics. (Am J Vet Res 2005;66:606–614)