Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, 1 Deaconess Road, Boston MA 02446, USA.
Respir Care. 2010 Feb;55(2):162-72; discussion 172-4.
Low-tidal-volume ventilation strategies are clearly beneficial in patients with acute lung injury and acute respiratory distress syndrome, but the optimal level of applied positive end-expiratory pressure (PEEP) is uncertain. In patients with high pleural pressure on conventional ventilator settings, under-inflation may lead to atelectasis, hypoxemia, and exacerbation of lung injury through "atelectrauma." In such patients, raising PEEP to maintain a positive transpulmonary pressure might improve aeration and oxygenation without causing over-distention. Conversely, in patients with low pleural pressure, maintaining a low PEEP would keep transpulmonary pressure low, avoiding over-distention and consequent "volutrauma." Thus, the currently recommended strategy of setting PEEP without regard to transpulmonary pressure is predicted to benefit some patients while harming others. Recently the use of esophageal manometry to identify the optimal ventilator settings, avoiding both under-inflation and over-inflation, was proposed. This method shows promise but awaits larger clinical trials to assess its impact on clinical outcomes.
低潮气量通气策略在急性肺损伤和急性呼吸窘迫综合征患者中显然是有益的，但应用呼气末正压通气（PEEP）的最佳水平尚不确定。在常规呼吸机设置下胸膜压力较高的患者中，过度充气可能会导致肺不张、低氧血症，并通过“肺不张性损伤”加重肺损伤。在这些患者中，提高 PEEP 以维持正的跨肺压可能会改善通气和氧合，而不会导致过度扩张。相反，在胸膜压力较低的患者中，保持低 PEEP 将使跨肺压保持较低，避免过度扩张和随之而来的“容积性损伤”。因此，目前不考虑跨肺压而设定 PEEP 的推荐策略预计会使一些患者受益，而使另一些患者受到伤害。最近，人们提出使用食管测压法来确定最佳的呼吸机设置，避免过度充气和充气不足。这种方法有一定的前景，但需要更大的临床试验来评估其对临床结果的影响。
