Abram Julia, Spraider Patrick, Wagner Julian, Ranalter Manuela, Gratl Alexandra, Lobenwein Daniela, Wipper Sabine, Putzer Gabriel, Hell Tobias, Tscholl Pia, Martini Judith
Department of Anesthesia and Intensive Care Medicine, Medical University Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria.
Department of Vascular Surgery, Medical University Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria.
Resusc Plus. 2025 Jun 21;25:101013. doi: 10.1016/j.resplu.2025.101013. eCollection 2025 Sep.
Hemorrhagic shock is a life-threatening event whereby low flow may lead to end-organ dysfunction. This is aggravated by mechanical ventilation, where a positive intrathoracic pressure further deteriorates venous filling of the heart. The aim of this study was to evaluate the effects of a mild negative end-expiratory pressure (NEEP) on mean arterial pressure compared to zero end-expiratory pressure (ZEEP) in a porcine hemorrhagic shock model.
In anesthetized pigs, hemorrhagic shock was induced by a standardized lesion in the common femoral artery. After achieving half of baseline arterial pressure, hemorrhage was stopped. Ventilation was then switched to either flow-controlled ventilation with ZEEP (0 cmHO, = 6) or NEEP (-5 cmHO, = 6). After 5 min, fluid resuscitation was initiated (30 ml/kg) over 60 min and the observation period ended after 120 min.
The primary outcome parameter mean arterial pressure was significantly improved within the first 15 min with NEEP compared to ZEEP (49 vs 40 mmHg, MD 9 (95% CI 2 to 15); = 0.031), but this effect diminished throughout fluid resuscitation. The cardiac index was similar in both groups. Evaluation of lung mechanics revealed a decrease in dynamic compliance (29 vs 44 ml/cmHO, MD -14 (95% CI -20 to -9); < 0.001) in the NEEP group without differences in gas exchange.
Application of -5 cmHO NEEP improved mean arterial pressure but not cardiac index during hemorrhagic shock and the first 15 min of fluid resuscitation compared to ZEEP. Thereby gas exchange performance was similar.
失血性休克是一种危及生命的状况，低血流可能导致终末器官功能障碍。机械通气会使这种情况恶化，因为胸腔内正压会进一步损害心脏的静脉充盈。本研究的目的是在猪失血性休克模型中，评估与呼气末零压力（ZEEP）相比，轻度呼气末负压（NEEP）对平均动脉压的影响。
在麻醉的猪身上，通过股总动脉的标准化损伤诱导失血性休克。在达到基线动脉压的一半后，停止出血。然后将通气切换为ZEEP（0 cmH₂O，n = 6）或NEEP（-5 cmH₂O，n = 6）的流量控制通气。5分钟后，在60分钟内开始液体复苏（30 ml/kg），观察期在120分钟后结束。
与ZEEP相比，NEEP在最初15分钟内显著改善了主要结局参数平均动脉压（49 vs 40 mmHg，MD 9（95% CI 2至15）；P = 0.031），但在整个液体复苏过程中这种效果减弱。两组的心脏指数相似。肺力学评估显示，NEEP组的动态顺应性降低（29 vs 44 ml/cmH₂O，MD -14（95% CI -20至-9）；P < 0.001），气体交换无差异。
与ZEEP相比，在失血性休克和液体复苏的最初15分钟内，应用-5 cmH₂O的NEEP可改善平均动脉压，但不能改善心脏指数。气体交换性能相似。
