RATIONALE The pathophysiological relationship between fluid administration, fluid balance, and mechanical ventilation in the development of lung injury is unclear. OBJECTIVES To quantify the relative contribution of mechanical power and fluid balance in the development of lung injury. METHODS Thirty-nine healthy female pigs, divided into four groups, were ventilated for 48 hours with high (~18J/min) or low (~6J/min) mechanical power; and high (~4L) or low (~1L) targeted fluid balance. MEASUREMENTS AND MAIN RESULTS We measured physiological variables e.g., end-expiratory lung gas volume, respiratory-system mechanics, gas-exchange and hemodynamics, and pathological variables, i.e., lung weight, wet-to-dry ratio, and histology score of lung injury. End-expiratory lung gas volume, respiratory system elastance, strain and oxygenation significantly worsened in the two groups assigned to receive high fluid balance, irrespective of the mechanical power received. All four groups had similar lung weight (i.e., lung edema), lung wet-to-dry ratio and pathological variables. Animals with higher fluid balance developed more ascites, which was associated with a decrease in end-expiratory lung gas volume. CONCLUSIONS In conclusion, our study did not detect a significant difference in lung injury between high and low mechanical power. Some damage is directly attributable to mechanical power, while additional injury appears to result indirectly from high fluid balance, which reduces end-expiratory lung gas volume, with ascites playing an important role in this process.

中文翻译：

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体液平衡对肺损伤发展的影响。


基本原理 液体给药、体液平衡和机械通气在肺损伤发展中的病理生理关系尚不清楚。目的 量化机械力和体液平衡在肺损伤发展中的相对贡献。方法 将 39 头健康母猪分为 4 组，以高 （~18J/min） 或低 （~6J/min） 机械功率通气 48 h;以及高 （~4L） 或低 （~1L） 目标体液平衡。测量和主要结果 我们测量了生理变量，例如呼气末肺气体量、呼吸系统力学、气体交换和血流动力学，以及病理变量，即肺重量、湿干比和肺损伤的组织学评分。无论接受的机械动力如何，被分配接受高液体平衡的两组的呼气末肺气量、呼吸系统弹性、应变和氧合都显着恶化。所有 4 组的肺重量 （即肺水肿） 、肺湿干比和病理变量相似。体液平衡较高的动物发生更多的腹水，这与呼气末肺气量的减少有关。结论 总之，我们的研究未检测到高机械功率和低机械功率之间的肺损伤存在显著差异。一些损伤直接归因于机械动力，而额外的损伤似乎是由高体液平衡间接导致的，这减少了呼气末肺气量，腹水在此过程中起着重要作用。