Antinociceptive and selected physiological effects of morphine and xylazine on tiletamine-zolazepam anesthesia in llamas

作者:Seddighi Reza*; Elliot Sarah B; Whitlock Brian K; Egger Christine M; Doherty Thomas J
来源:Veterinary Anaesthesia and Analgesia, 2014, 41(4): 365-371.
DOI:10.1111/vaa.12128

摘要

Objective Evaluate antinociception, anesthesia, and recovery in llamas given tiletamine-zolazepam (TZ) with either morphine, xylazine, morphine and xylazine, or saline. Study design Randomized crossover experimental study. Animals Six healthy, adult intact male llamas. Methods Llamas were given each of four treatments intramuscularly with a 1-week washout: TZ (2mgkg-1) combined with either morphine (0.5mgkg-1; M), xylazine (0.15mgkg-1; X), morphine (0.5mgkg-1) and xylazine (0.15mgkg-1) (MX), or saline (C). Llamas breathed room air during the experiment. Characteristics of anesthesia, recovery, and selected cardiopulmonary variables were recorded. Antinociception was assessed by clamping a claw at 5-minute intervals. Data were analyzed using a mixed-model anova and Tukey-Kramer test, and are expressed as least squares mean +/- SEM. Significance was set at p<0.05. Results No llama in the control group demonstrated antinociception. Antinociception was longest with treatment MX, followed by treatments X and M, respectively. Heart rates in llamas given treatments X and MX were significantly lower than with other treatments. The respiratory rate in llamas given treatment C was greater (p<0.05) than for all other treatments, however, the respiratory rate was not significantly different among treatments X, M and MX. The PaO2 for llamas given MX remained <60mmHg throughout the 20minute period of blood gas analysis. Mean arterial blood pressure in llamas in treatment MX was less than for treatments M or C. Conclusion and clinical relevance The combination of morphine (0.5mgkg-1) and xylazine (0.15mgkg-1) increased the duration of antinociception compared with xylazine alone, in TZ-anesthetized llamas. Treatments X, M and MX were associated with hypoxemia (PaO2<60mmHg).

  • 出版日期2014-7