Department of Anesthesiology and Pain Medicine, Naval Medical Center Portsmouth.
Clinical Investigation Department, Naval Medical Center Portsmouth, Portsmouth, Virginia.
Comp Med. 2022 Feb 1;72(1):38-44. doi: 10.30802/AALAS-CM-21-000080. Epub 2021 Dec 7.
The Yorkshire-cross swine model is a valuable translational model commonly used to study cardiovascular physiology and response to insult. Although the effects of vasoactive medications have been well described in healthy swine, the effects of these medications during hemorrhagic shock are less studied. In this study, we sought to expand the utility of the swine model by characterizing the hemodynamic changes that occurred after the administration of commonly available vasoactive medications during euvolemic and hypovolemic states. To this end, we anesthetized and established femoral arterial, central venous, and pulmonary arterial access in 15 juvenile Yorkshire-cross pigs. The pigs then received a series of rapidly metabolized but highly vasoactive medications in a standard dosing sequence. After completion of this sequence, each pig underwent a 30-mL/kg hemorrhage over 10 min, and the standard dosing sequence was repeated. We then used standard sta- tistical techniques to compare the effects of these vasoactive medications on a variety of hemodynamic parameters between the euvolemic and hemorrhagic states. All subjects completed the study protocol. The responses in the hemorrhagic state were often attenuated or even opposite of those in the euvolemic state. For example, phenylephrine decreased the mean arterial blood pressure during the euvolemic state but increased it in the hemorrhagic state. These results clarify previously poorly defined responses to commonly used vasoactive agents during the hemorrhagic state in swine. Our findings also demonstrate the need to consider the complex and dynamic physiologic state of hemorrhage when anticipating the effects of vasoactive drugs and planning study protocols.
约克夏杂交猪模型是一种常用于研究心血管生理学和对损伤反应的有价值的转化模型。虽然血管活性药物在健康猪中的作用已得到很好的描述，但这些药物在失血性休克中的作用研究较少。在这项研究中，我们试图通过描述在等容和低血容量状态下给予常用血管活性药物后发生的血流动力学变化，来扩展猪模型的用途。为此，我们麻醉并建立了 15 头幼年约克夏杂交猪的股动脉、中心静脉和肺动脉通路。然后，这些猪按照标准剂量顺序接受了一系列快速代谢但高度血管活性的药物。在完成这个序列后，每头猪在 10 分钟内经历了 30 毫升/公斤的出血，然后重复标准剂量序列。然后，我们使用标准统计技术比较了这些血管活性药物在等容和出血状态下对各种血流动力学参数的影响。所有研究对象均完成了研究方案。出血状态下的反应通常减弱甚至与等容状态下的反应相反。例如，去氧肾上腺素在等容状态下降低平均动脉血压，但在出血状态下升高。这些结果阐明了以前在猪的出血状态下对常用血管活性药物反应不佳的问题。我们的研究结果还表明，在预测血管活性药物的作用和制定研究方案时，需要考虑到出血时复杂和动态的生理状态。
