Gattinoni Luciano, Chiumello Davide, Carlesso Eleondra, Valenza Franco
Institute of Anesthesia and Critical Care, University of Milan, Policlinico - IRCCS Hospital, Milan, Italy.
Crit Care. 2004 Oct;8(5):350-5. doi: 10.1186/cc2854. Epub 2004 May 7.
The importance of chest wall elastance in characterizing acute lung injury/acute respiratory distress syndrome patients and in setting mechanical ventilation is increasingly recognized. Nearly 30% of patients admitted to a general intensive care unit have an abnormal high intra-abdominal pressure (due to ascites, bowel edema, ileus), which leads to an increase in the chest wall elastance. At a given applied airway pressure, the pleural pressure increases according to (in the static condition) the equation: pleural pressure = airway pressure x (chest wall elastance/total respiratory system elastance). Consequently, for a given applied pressure, the increase in pleural pressure implies a decrease in transpulmonary pressure (airway pressure - pleural pressure), which is the distending force of the lung, implies a decrease of the strain and of ventilator-induced lung injury, implies the need to use a higher airway pressure during the recruitment maneuvers to reach a sufficient transpulmonary opening pressure, implies hemodynamic risk due to the reductions in venous return and heart size, and implies a possible increase of lung edema, partially due to the reduced edema clearance. It is always important in the most critically ill patients to assess the intra-abdominal pressure and the chest wall elastance.
胸壁弹性在急性肺损伤/急性呼吸窘迫综合征患者特征描述及机械通气设置中的重要性日益受到认可。入住普通重症监护病房的患者中，近30%存在异常高的腹内压（由于腹水、肠水肿、肠梗阻），这会导致胸壁弹性增加。在给定的气道压力下，胸膜压力（在静态条件下）根据以下公式增加：胸膜压力 = 气道压力×（胸壁弹性/总呼吸系统弹性）。因此，对于给定的施加压力，胸膜压力的增加意味着跨肺压（气道压力 - 胸膜压力）降低，而跨肺压是肺的扩张力，这意味着应变和呼吸机诱导的肺损伤减少，意味着在肺复张操作期间需要使用更高的气道压力以达到足够的跨肺开放压力，意味着由于静脉回流和心脏大小减小而存在血流动力学风险，并且意味着肺水肿可能增加，部分原因是水肿清除减少。对于病情最危重的患者，评估腹内压和胸壁弹性始终很重要。
