Anesthesia with Diazepam-Ketamine and Midazolam-Ketamine and its Reversal with Flumazenil in the Chinese Stripe-Necked Turtle (Ocadia sinensis)

Autor: Sin-Yi Jiang, 蔣馨儀
Rok vydání: 2007
Druh dokumentu: 學位論文 ; thesis
Popis: 95
Chelonians frequently require anesthesia or sedation to perform clinical procedures. Many of the commonly used anesthetic agents were designed for use in mammalian species. Given the differences in respiratory anatomy and physiology, the response in chelonians to these agents often differs from the response in mammalian species. The aim of the study was to determine the anesthetic effect of diazepam–ketamine (DIZ-KET) and midazolam-ketamine (MID-KET) in the chinese stripe-necked turtle (Ocadia sinensis), and to observed the ability of specific antagonist flumazenil (FMZ) to antagonize the effect of DIZ-KET (2-90 mg/kg) and MID-KET (2-90 mg/kg), respectively. The experiments also aimed to evaluate whether weight was a factor in the anesthetic effect on the turtles. The dosage groups in the study included DIZ-KET (2-60, 4-60 and 2-90 mg/kg, n=6) and MID-KET (2-60, 4-60 and 2-90 mg/kg, n=6). Anesthetic depth was based on testing protective reflexes (palpebral reflex, corneal reflex, jaw tone, head withdrawal reflex, and limbs withdrawal reflexes/ by touching or pinching). The induction time, duration of anesthesia, duration of surgical anesthesia and recovery time were recorded. The duration of each anesthesia level were also recorded. All dosages of DIZ-KET and MID-KET could achieve levels of anesthesia. Both dosages of DIZ (2 mg/kg) and MID (2 mg/kg) with an increased KET dosage (from 60 to 90 mg/kg) shortened the time of diminished corneal reflex (from 5.3 ± 0.8 to 2.2 ± 0.3 min) and palpebral reflex (from 3.0 ± 0.4 to 1.3 ± 0.2 min) and significantly prolonged the duration of anesthesia (from 97.2 ± 18.0 to 187.8 ± 28.8 min vs. from 103.3 ± 9.4 to 181.8 ± 19.5 min), but did not reduce the recovery time. In the experiments factoring in weight, the same dosage of DIZ-KET (2-90 mg/kg) in heavier turtles (mean: 2.66 ± 0.07 kg ; range: 2.48-3.00 kg) had much longer periods of surgical anesthesia (83 ± 15 min) than in the lighter turtles (mean: 1.03 ± 0.04 kg ; range: 0.91-1.13 kg) (13 ± 5 min), but there were no significant differences between these two groups in induction time, duration of anesthesia, or recovery time. Flumazenil was effective on reversing the anesthetic effects of DIZ-KET and MID-KET within 1-2 minutes and significantly shortened the duration of anesthesia, the recovery time for all the reflexes, and the complete recovery time of MID-KET (2-90 mg/kg) regimen. The dosage groups revealed that DIZ-KET and MID-KET could increase the heart rate and the respiratory rate. However, the use of antagonist did not affect the heart rate or the respiratory rate significantly. Although all dosages of DIZ-KET and MID-KET regimens induced anesthesia, the results indicated that DIZ-KET and MID-KET at 2-90 mg/kg induced the most stable surgical anesthesia. The anesthetic effects were effectively and safely antagonized by 0.05 mg/kg flumazenil, which could be applied clinically to reduce the duration of anesthesia.
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