Assistance Publique-Hôpitaux de Paris, University Hospital Ambroise Paré, Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Boulogne-Billancourt, France.
University of Versailles Saint-Quentin en Yvelines, Faculty of Medicine Paris Ile-de-France Ouest, Saint-Quentin en Yvelines, France.
J Appl Physiol (1985). 2017 Jun 1;122(6):1373-1378. doi: 10.1152/japplphysiol.00958.2016. Epub 2017 Mar 30.
Mean systemic filling pressure (P) defines the pressure measured in the venous-arterial system when the cardiac output is nil. Its estimation has been proposed in patients with beating hearts by building the venous return curve, using different pairs of right atrial pressure/cardiac output during mechanical ventilation. We raised the hypothesis according to which the P is altered by tidal ventilation and positive end-expiratory pressure (PEEP), which would challenge this extrapolation method based on cardiopulmonary interactions. We conducted a two-center, noninterventional, observational, and prospective study, using an arterial and a venous catheter to measure the pressure in the circulatory system at the time of death in critically ill, mechanically ventilated patients with a PEEP. Arterial (P) and venous pressures (P) were recorded in five conditions: at end expiration and end inspiration with and without PEEP and finally once the ventilator was disconnected. P and P did not differ in any experimental conditions. Tidal ventilation increased P and P by 2.4 and 1.9 mmHg, respectively, whereas PEEP increased both values by 1.2 and 1 mmHg, respectively. After disconnection of the ventilator, P and P were 10.0 ± 4.2 and 9.9 ± 4.2 mmHg, respectively. P increases during mechanical ventilation, with an effect of tidal ventilation and PEEP. This calls into question the validity of its evaluation in heart-beating patients using cardiopulmonary interactions during mechanical ventilation. The physiology of the mean systemic filling pressure (P) is not well understood in human beings. This study is the first report of a tidal ventilation- and positive end-expiratory pressure-related increase in P in critically ill patients. The results challenge the utility and the value estimating P in heart-beating patients by reconstruction of the venous return curve using varying inflation pressures.
平均体循环充盈压（P）定义为心脏输出量为零时测量的静脉-动脉系统压力。已经提出了在有心跳的患者中通过构建静脉回流曲线来估计其值的方法，使用机械通气期间不同的右心房压力/心输出量对进行。根据潮气量通气和呼气末正压（PEEP）会改变 P 的假设，这将挑战基于心肺相互作用的这种外推方法。我们进行了一项两中心、非干预性、观察性和前瞻性研究，使用动脉和静脉导管在有 PEEP 的机械通气的危重病患者死亡时测量循环系统中的压力。在五个条件下记录动脉压（P）和静脉压（P）：在呼气末和吸气末，有和没有 PEEP，最后一次在呼吸机断开时。在任何实验条件下，P 和 P 都没有差异。潮气量通气分别使 P 和 P 增加 2.4 和 1.9 mmHg，而 PEEP 分别使这两个值增加 1.2 和 1 mmHg。在呼吸机断开后，P 和 P 分别为 10.0±4.2mmHg 和 9.9±4.2mmHg。机械通气期间 P 增加，潮气量通气和 PEEP 有影响。这质疑了在机械通气期间使用心肺相互作用评估有心跳患者时其评估的有效性。人类对平均体循环充盈压（P）的生理学了解甚少。这是首次报道在危重病患者中，P 随潮气量通气和呼气末正压而增加。结果挑战了通过使用不同充气压力重建静脉回流曲线来估计有心跳患者 P 的实用性和价值。
