Nieman Gary F, Satalin Joshua, Andrews Penny, Aiash Hani, Habashi Nader M, Gatto Louis A
Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, USA.
Cardiopulmonary Critical Care Lab, Department of Surgery, Upstate Medical University, 750 East Adams Street, Syracuse, NY, 13210, USA.
Intensive Care Med Exp. 2017 Dec;5(1):8. doi: 10.1186/s40635-017-0121-x. Epub 2017 Feb 2.
It has been shown that mechanical ventilation in patients with, or at high-risk for, the development of acute respiratory distress syndrome (ARDS) can be a double-edged sword. If the mechanical breath is improperly set, it can amplify the lung injury associated with ARDS, causing a secondary ventilator-induced lung injury (VILI). Conversely, the mechanical breath can be adjusted to minimize VILI, which can reduce ARDS mortality. The current standard of care ventilation strategy to minimize VILI attempts to reduce alveolar over-distension and recruitment-derecruitment (R/D) by lowering tidal volume (Vt) to 6 cc/kg combined with adjusting positive-end expiratory pressure (PEEP) based on a sliding scale directed by changes in oxygenation. Thus, Vt is often but not always set as a "one-size-fits-all" approach and although PEEP is often set arbitrarily at 5 cmHO, it may be personalized according to changes in a physiologic parameter, most often to oxygenation. However, there is evidence that oxygenation as a method to optimize PEEP is not congruent with the PEEP levels necessary to maintain an open and stable lung. Thus, optimal PEEP might not be personalized to the lung pathology of an individual patient using oxygenation as the physiologic feedback system. Multiple methods of personalizing PEEP have been tested and include dead space, lung compliance, lung stress and strain, ventilation patterns using computed tomography (CT) or electrical impedance tomography (EIT), inflection points on the pressure/volume curve (P/V), and the slope of the expiratory flow curve using airway pressure release ventilation (APRV). Although many studies have shown that personalizing PEEP is possible, there is no consensus as to the optimal technique. This review will assess various methods used to personalize PEEP, directed by physiologic parameters, necessary to adaptively adjust ventilator settings with progressive changes in lung pathophysiology.
研究表明，对于已发生或有急性呼吸窘迫综合征（ARDS）发生风险的患者，机械通气可能是一把双刃剑。如果机械通气参数设置不当，可能会加重与ARDS相关的肺损伤，导致继发性呼吸机诱导性肺损伤（VILI）。相反，可调整机械通气以尽量减少VILI，从而降低ARDS的死亡率。当前用于尽量减少VILI的标准护理通气策略试图通过将潮气量（Vt）降至6 cc/kg，并根据氧合变化按滑动标尺调整呼气末正压（PEEP），来减少肺泡过度扩张和再灌注-去灌注（R/D）。因此，Vt通常但并非总是采用“一刀切”的方法设置，尽管PEEP通常随意设置为5 cmH₂O，但也可根据生理参数的变化进行个性化设置，最常见的是根据氧合情况。然而，有证据表明，将氧合作为优化PEEP的方法与维持肺开放和稳定所需的PEEP水平并不一致。因此，使用氧合作为生理反馈系统时，最佳PEEP可能无法针对个体患者的肺部病理情况进行个性化设置。已经测试了多种个性化设置PEEP的方法，包括死腔、肺顺应性、肺应力和应变、使用计算机断层扫描（CT）或电阻抗断层扫描（EIT）的通气模式、压力/容积曲线（P/V）上的拐点以及使用气道压力释放通气（APRV）的呼气流量曲线斜率。尽管许多研究表明可以对PEEP进行个性化设置，但对于最佳技术尚无共识。本综述将评估各种用于根据生理参数对PEEP进行个性化设置的方法，这些参数对于随着肺部病理生理学的逐渐变化自适应调整呼吸机设置是必要的。
