Akaraphutiporn Ekkapol, Bunnag Patmanachatr, Limprasutr Vudhiporn, Rattanapinyopituk Kasem, Durongphongtorn Sumit, Pablo Luisito S, Sharp Patrick, Pacharinsak Cholawat, Wangdee Chalika
1Department of Veterinary Surgery, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
2Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
J Am Assoc Lab Anim Sci. 2025 Jun 1;64(4):1-7. doi: 10.30802/AALAS-JAALAS-25-048.
In this study we investigated the sedative, anesthetic, and pulmonary histopathologic effects of dexmedetomidine/morphine (DM) and xylazine/morphine (XM) in sheep. We hypothesized that DM would provide profound sedation and better maintain physiologic parameters under anesthesia than XM in sheep undergoing laparoscopic surgery. Nineteen male sheep were premedicated with either DM (dexmedetomidine [0.006 mg/kg] and morphine [0.3 mg/kg]) or XM (xylazine [0.1 mg/kg] and morphine [0.3 mg/kg]). After DM or XM administration, 3 blinded veterinarians evaluated sedation scores (0 [no sedation], 1 [mild], 2 [moderate], 3 [severe]). Sheep were induced with intravenous tiletamine/zolazepam, intubated, and maintained with isoflurane in 100% oxygen. Anesthetic parameters were monitored for 60 min, including heart rate, respiratory rate, indirect blood pressure, oxygen saturation, end-tidal carbon dioxide, body temperature, arterial blood gas analysis, and isoflurane requirement. At the end of the procedure, the sheep were euthanized, and lung pathology (pulmonary edema) was assessed. The results showed that the sedation scores did not differ between DM (0.8 [0.4 to 1.0]) and XM (1.0 [1.0 to 1.0]). In addition, the anesthetic parameters were comparable between the groups, but the DM group exhibited a higher heart rate than the XM group. Finally, marked pulmonary changes, consistent with pulmonary edema, were observed in the XM group. In conclusion, DM and XM provided similar sedation and physiologic stability under isoflurane anesthesia, but DM may help minimize bradycardia and was associated with less evidence of pulmonary edema.
在本研究中，我们调查了右美托咪定/吗啡（DM）和赛拉嗪/吗啡（XM）对绵羊的镇静、麻醉及肺组织病理学影响。我们假设，在接受腹腔镜手术的绵羊中，DM比XM能提供更深度的镇静，并在麻醉状态下更好地维持生理参数。19只雄性绵羊分别用DM（右美托咪定[0.006 mg/kg]和吗啡[0.3 mg/kg]）或XM（赛拉嗪[0.1 mg/kg]和吗啡[0.3 mg/kg]）进行术前用药。给予DM或XM后，3名盲法兽医评估镇静评分（0[无镇静]、1[轻度]、2[中度]、3[重度]）。绵羊静脉注射替来他明/唑拉西泮诱导麻醉、插管，并在100%氧气中用异氟烷维持麻醉。监测麻醉参数60分钟，包括心率、呼吸频率、间接血压、血氧饱和度、呼气末二氧化碳、体温、动脉血气分析及异氟烷需求量。手术结束时，对绵羊实施安乐死，并评估肺病理学（肺水肿）情况。结果显示，DM组（0.8[0.4至1.0]）和XM组（1.0[1.0至1.0]）的镇静评分无差异。此外，两组间麻醉参数具有可比性，但DM组心率高于XM组。最后，在XM组观察到与肺水肿一致的明显肺部变化。总之，在异氟烷麻醉下，DM和XM提供相似的镇静效果和生理稳定性，但DM可能有助于减少心动过缓，且与肺水肿证据较少相关。
