Effects of isoflurane anesthesia on equine liver function.
Abstract: The acute 2-hour effects of isoflurane anesthesia on liver function and biliary excretion were examined in 2 ponies prepared surgically with chronic external biliary fistulas (T-tubes). Studies were conducted 2 to 8 months postoperatively with the enterohepatic circulation held intact between studies. Bile acid infusion IV (8.1 to 8.8 mumol/min) helped maintain bile flow and bile acid and bilirubin excretion during complete biliary diversion throughout each study. Following 3-hour control periods, anesthesia was induced and maintained at 1.3 to 1.5 minimal alveolar concentration plus O2 (spontaneous breathing) for 2 hours. Compared with the immediate 2-hour preanesthesia values, isoflurane caused significant increases in PCV (27%) and biliary bilirubin excretion (24%). However, no significant differences were detected in plasma or biliary bilirubin concentrations, biliary bile acid concentration or excretion, bile flow, or plasma aspartate aminotransferase concentrations between preanesthesia control and anesthesia periods. The results indicate that although isoflurane anesthesia enhanced hepatic bilirubin excretion, its effects on hepatic bilirubin formation and/or clearance are modest, compared with effects of halothane anesthesia which have previously been shown to enhance equine bilirubin excretion by 138% and reduce bile acid excretion by 27%. Isoflurane anesthesia in ponies does not appear to affect hepatic bile acid transport or bile formation significantly.
Publication Date: 1984-04-01 PubMed ID: 6731976
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- Comparative Study
- Journal Article
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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The research study investigates the effects of isoflurane anesthesia on liver function in ponies. Isoflurane anesthesia was found to increase red blood cell volume and bilirubin excretion in bile, however, it does not significantly impact the transportation or formation of bile acid in the liver.
Research Method
- The research was conducted on two ponies that were prepared for this study by surgically inserting chronic external biliary fistulas (T-tubes). These tubes ensure continuous bile flow.
- The experiments were done 2 to 8 months after the surgery, while maintaining intact enterohepatic circulation (the circulation of bile acids from the liver to the intestine and back).
- A bile acid infusion was applied intravenously to each pony to maintain bile flow and excretion of bilirubin and bile acid during the complete diversion of bile flow.
- After controlling the variables for three hours, anesthesia was induced with 1.3 – 1.5 minimal alveolar concentration along with supplementary oxygen, and maintained for the next two hours.
Key Findings
- Post-anesthesia values indicated that isoflurane significantly increased the packed cell volume (PCV) and biliary bilirubin excretion by 27% and 24% respectively.
- However, there were no considerable variances in plasma bilirubin concentrations, bile acid concentration or excretion, bile flow, or plasma aspartate aminotransferase concentrations – a liver function indicator.
- In comparison to halothane anesthesia, which was previously found to increase equine bilirubin excretion by 138% and reduce bile acid excretion by 27%, the effects of isoflurane on hepatic bilirubin formation and clearance were documented as modest.
Implications of the Study
- The findings of the research suggest that while isoflurane anesthesia affects hepatic bilirubin excretion, it does not significantly alter the formation or clearance of bilirubin.
- Additionally, it does not seem to heavily influence hepatic bile acid transport or bile formation, which are crucial for digestive and liver functioning in ponies.
- The research paves the way for understanding and comparison of different types of anesthesia and their effects on liver function in equines.
Cite This Article
APA
Engelking LR, Dodman NH, Hartman G, Valdez H.
(1984).
Effects of isoflurane anesthesia on equine liver function.
Am J Vet Res, 45(4), 616-619.
Publication
Researcher Affiliations
MeSH Terms
- Anesthesia, Inhalation / veterinary
- Animals
- Bile / drug effects
- Bile / physiology
- Bile Acids and Salts / metabolism
- Bilirubin / metabolism
- Female
- Halothane / pharmacology
- Horses / metabolism
- Humans
- Isoflurane / pharmacology
- Liver / drug effects
- Liver / metabolism
- Methyl Ethers / pharmacology
Grant Funding
- ISO7RR0582-01 / NCRR NIH HHS
Citations
This article has been cited 1 times.- Ahmadi-Noorbakhsh S, Farajli Abbasi M, Ghasemi M, Bayat G, Davoodian N, Sharif-Paghaleh E, Poormoosavi SM, Rafizadeh M, Maleki M, Shirzad-Aski H, Kargar Jahromi H, Dadkhah M, Khalvati B, Safari T, Behmanesh MA, Khoshnam SE, Houshmand G, Talaei SA. Anesthesia and analgesia for common research models of adult mice.. Lab Anim Res 2022 Dec 13;38(1):40.
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