Scultetus Anke H, Jefferson Michelle A, Haque Ashraful, Hubbell Jordan N, Arnaud Francoise G, Moon-Massat Paula, McCarron Richard M, Malone Debra L
Neuro Trauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.
Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814.
Mil Med. 2020 Jan 7;185(Suppl 1):57-66. doi: 10.1093/milmed/usz248.
Rapid aeromedical evacuation (AE) is standard of care in current conflicts. However, not much is known about possible effects of hypobaric conditions. We investigated possible effects of hypobaria on organ damage in a swine model of acute lung injury.
Lung injury was induced in anesthetized swine via intravenous oleic acid infusion. After a stabilization phase, animals were subjected to a 4 hour simulated AE at 8000 feet (HYPO). Control animals were kept at normobaria. After euthanasia and necropsy, organ damage was assessed by combined scores for hemorrhage, inflammation, edema, necrosis, and microatelectasis.
Hemodynamic, neurological, or hematologic measurements were similar prior to transport. Hemodynamic instability became apparent during the last 2 hours of transport in the HYPO group. Histological injury scores in the HYPO group were higher for all organs (lung, kidney, liver, pancreas, and adrenal glands) except the brain, with the largest difference in the lungs (P < 0.001).
Swine with mild acute lung injury subjected to a 4 hour simulated AE showed more injury to most organs and, in particular, to the lungs compared with ground transport. This may exacerbate otherwise subclinical pathology and, eventually, manifest as abnormalities in gas exchange or possibly end-organ function.
在当前冲突中，快速空中医疗后送（AE）是标准治疗手段。然而，关于低压环境可能产生的影响，我们所知甚少。我们在急性肺损伤猪模型中研究了低压对器官损伤的可能影响。
通过静脉注射油酸在麻醉的猪身上诱导肺损伤。在稳定期后，将动物置于8000英尺（低压环境）进行4小时模拟空中医疗后送。对照动物保持在常压环境。安乐死和尸检后，通过对出血、炎症、水肿、坏死和微小肺不张的综合评分评估器官损伤。
转运前的血流动力学、神经学或血液学测量结果相似。在低压组转运的最后2小时出现血流动力学不稳定。除脑外，低压组所有器官（肺、肾、肝、胰腺和肾上腺）的组织学损伤评分均更高，肺的差异最大（P < 0.001）。
与地面转运相比，患有轻度急性肺损伤的猪在4小时模拟空中医疗后送后，大多数器官尤其是肺受到的损伤更大。这可能会使原本亚临床的病理状况恶化，并最终表现为气体交换异常或可能的终末器官功能异常。
