Peer-reviewed veterinary case report
How anesthesia and surgery affect thyroid tests in dogs
By Wood, M A et al.·Published in Journal of veterinary internal medicine·2009·Department of Small Animal Clinical Sciences, United States·View original on PubMed →
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Original publication title: Influence of isoflurane general anesthesia or anesthesia and surgery on thyroid function tests in dogs.
- Species:
- dog
Plain-English summary
A study involving 15 healthy dogs found that general anesthesia and surgery can affect thyroid hormone levels. Specifically, the levels of certain thyroid hormones decreased shortly after anesthesia and surgery but showed signs of recovery within a day or two. For example, serum thyroxine (T4) levels dropped significantly right after the procedures but began to rise again by the 24-hour mark in dogs that underwent surgery. This suggests that if your dog needs anesthesia or surgery, their thyroid function may temporarily change, but they typically recover afterward.
People also search for: dog anesthesia effects on thyroid · dog surgery thyroid hormone levels · isoflurane anesthesia dog recovery
Abstract
BACKGROUND: Anesthesia and surgery affect thyroid function tests in humans but have not been studied in dogs. HYPOTHESIS: Anesthesia and anesthesia with surgery will affect thyroid function tests in dogs. ANIMALS: Fifteen euthyroid dogs. METHODS: Prospective, controlled, interventional study. Dogs were assigned to one of 3 groups: control, general anesthesia, and general anesthesia plus abdominal exploratory surgery. Dogs in the anesthesia and surgery groups were premedicated with acepromazine and morphine, induced with propofol, and maintained on isoflurane. Samples for measurement of serum thyroxine (T4), free T4 (fT4) by equilibrium dialysis, triiodothyronine (T3), reverse T3 (rT3), and thyroid-stimulating hormone concentrations were collected from each dog immediately before premedication, at multiple times during anesthesia, surgery, 4, 8, 12, 24, 36, and 48 hours after anesthesia, once daily for an additional 5 days, and once 14 days after anesthesia. Sampling was performed at identical times in the control group. RESULTS: Serum T4 decreased significantly from baseline in the surgery and anesthesia groups compared with the control group at 0.33 (P= 0.043) and 1 hour (P= 0.018), and 2 (P= 0.031) and 4 hours (P= 0.037), respectively, then increased significantly in the surgery group compared with the control group at 24 hours (P= 0.005). Serum T3 decreased significantly from baseline in the anesthesia group compared with the control group at 1 hour (P= 0.034). Serum rT3 increased significantly from baseline in the surgery group compared with the control and anesthesia groups at 8 (P= 0.026) and 24 hours (P= 0.0001) and anesthesia group at 8, 12, 24, and 36 hours (P= 0.004, P= 0.016, P= 0.004, and P= 0.014, respectively). Serum fT4 increased significantly from baseline in the surgery group compared to the control at 24 hours (P= 0.006) and at day 7 (P= 0.037) and anesthesia group at 48 hours (P= 0.023). CONCLUSIONS AND CLINICAL IMPORTANCE: Surgery and anesthesia have a significant effect on thyroid function tests in dogs.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/19138380/