Finfer S, Rocker G
Intensive Therapy Unit, John Radcliffe Hospital, Oxford, U.K.
Anaesth Intensive Care. 1996 Oct;24(5):569-73. doi: 10.1177/0310057X9602400511.
It is now widely accepted that mechanical ventilation may damage the lung, but the mechanism of lung damage is not clear. Possible causes include overdistension of aerated alveoli by inappropriately large tidal volumes (volutrauma), shear stresses generated during the recruitment and de-recruitment of lung units at the junction of aerated and collapsed lung, and infective or ischaemic necrosis of persistently collapsed lung. Computerized tomography allows noninvasive assessment of lung structure during and after acute lung injury, and may provide insight into the mechanism of lung damage. Using serial high resolution computed tomography we documented lung structure one month after recovery from severe protracted adult respiratory distress syndrome (ARDS) in three patients who required mechanical ventilation for between 86 and 97 days; the computed tomograms were repeated at between 5 and 14 months. All three patients had persistent abnormalities of lung structure which were most marked in the anterior regions of the lung. These findings suggest that overdistension of non-dependent lung regions in the main mechanism of lung damage persisting after recovery from severe protracted ARDS.
目前人们普遍认为机械通气可能会损害肺，但肺损伤的机制尚不清楚。可能的原因包括不适当的大潮气量导致充气肺泡过度扩张（容积伤）、在充气肺和萎陷肺交界处肺单位复张和再萎陷过程中产生的剪切应力，以及持续萎陷肺的感染性或缺血性坏死。计算机断层扫描能够对急性肺损伤期间及之后的肺结构进行无创评估，并可能有助于深入了解肺损伤的机制。我们对3例因严重成人呼吸窘迫综合征（ARDS）接受机械通气86至97天的患者，在从严重迁延性ARDS恢复1个月后，使用系列高分辨率计算机断层扫描记录其肺结构；在5至14个月期间重复进行计算机断层扫描。所有3例患者均有持续的肺结构异常，在肺前部最为明显。这些发现表明，在从严重迁延性ARDS恢复后持续存在的肺损伤的主要机制是非依赖肺区域的过度扩张。
