Bennett Rachel C, Steffey Eugene P, Kollias-Baker Cynthia, Sams Richard
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Am J Vet Res. 2004 Apr;65(4):519-26. doi: 10.2460/ajvr.2004.65.519.
To quantitate the dose and time-related effects of morphine sulfate on the anesthetic sparing effect of xylazine hydrochloride in halothane-anesthetized horses and determine the associated plasma xylazine and morphine concentration-time profiles.
6 healthy adult horses.
Horses were anesthetized 3 times to determine the minimum alveolar concentration (MAC) of halothane in O2 and characterize the anesthetic sparing effect (ie, decrease in MAC of halothane) by xylazine (0.5 mg/kg, i.v.) administration followed immediately by i.v. administration of saline (0.9% NaCI) solution, low-dose morphine (0.1 mg/kg), or high-dose morphine (0.2 mg/kg). Selected parameters of cardiopulmonary function were also determined over time to verify consistency of conditions.
Mean (+/- SEM) MAC of halothane was 1.05 +/- 0.02% and was decreased by 20.1 +/- 6.6% at 49 +/- 2 minutes following xylazine administration. The amount of MAC reduction in response to xylazine was time dependent. Addition of morphine to xylazine administration did not contribute further to the xylazine-induced decrease in MAC (reductions of 21.9 +/- 1.2 and 20.7 +/- 1.5% at 43 +/- 4 and 40 +/- 4 minutes following xylazine-morphine treatments for low- and high-dose morphine, respectively). Overall, cardiovascular and respiratory values varied little among treatments. Kinetic parameters describing plasma concentration-time curves for xylazine were not altered by the concurrent administration of morphine.
Administration of xylazine decreases the anesthetic requirement for halothane in horses. Concurrent morphine administration to anesthetized horses does not alter the anesthetic sparing effect of xylazine or its plasma concentration-time profile.
定量硫酸吗啡对氟烷麻醉马匹中盐酸赛拉嗪麻醉增效作用的剂量和时间相关效应，并确定相关的血浆赛拉嗪和吗啡浓度-时间曲线。
6匹健康成年马。
对马匹进行3次麻醉，以确定O2中氟烷的最低肺泡浓度（MAC），并通过静脉注射赛拉嗪（0.5mg/kg）后立即静脉注射生理盐水（0.9%NaCl）溶液、低剂量吗啡（0.1mg/kg）或高剂量吗啡（0.2mg/kg）来表征麻醉增效作用（即氟烷MAC降低）。还随时间测定选定的心肺功能参数，以验证条件的一致性。
氟烷的平均（±标准误）MAC为1.05±±0.02%，赛拉嗪给药后49±±2分钟降低了20.1±±6.6%。赛拉嗪引起的MAC降低量与时间有关。在赛拉嗪给药中加入吗啡并未进一步促进赛拉嗪引起的MAC降低（赛拉嗪-吗啡联合处理后，低剂量和高剂量吗啡分别在43±±4分钟和40±±4分钟时MAC降低21.9±±1.2%和20.7±±1.5%）。总体而言，各处理之间的心血管和呼吸值变化不大。描述赛拉嗪血浆浓度-时间曲线的动力学参数不受同时给予吗啡的影响。
赛拉嗪给药可降低马匹对氟烷的麻醉需求。对麻醉马匹同时给予吗啡不会改变赛拉嗪的麻醉增效作用或其血浆浓度-时间曲线。
