Department of Intensive Medicine, Pontifical Catholic University of Chile, Santiago, Chile.
Minerva Anestesiol. 2011 Apr;77(4):418-26.
Overdistension and cyclic recruitment-derecruitment contribute to ventilator-induced lung injury. High tidal volumes are thought to increase mortality mainly by inducing overdistension. However, experimental evidence suggests that tidal volume (VT) may also influence cyclic recruitment-derecruitment. Our main goal was to determine whether high tidal volumes increase cyclic recruitment-derecruitment in acute respiratory distress syndrome (ARDS) patients, as measured by dynamic computed tomography (CT).
We studied 9 ARDS patients with diffuse attenuations on CT who underwent a protocol including 2 ventilatory modes: (a) VT 6 mL/kg, respiratory rate 30/min, PEEP 9 cmH2O, (b) VT 12 mL/kg, respiratory rate 15/min, PEEP 9 cmH2O. A dynamic computed tomography of 8 seconds on a fixed transverse region was performed during each ventilator mode. Cyclic recruitment-derecruitment was determined as non-aerated tissue variation between inspiration and expiration and was expressed as % of lung tissue weight.
VT 12 mL/kg exhibited less non-aerated tissue at expiration compared to VT 6 ml/kg (40.15 [35.94-56.00] and 45.31 [37.95-59.32], respectively, P<0.05). However, VT 12 ml/kg increased cyclic recruitment-derecruitment compared to VT 6 mL/kg (7.32 [6.58-9.29] mL/kg vs. 4.51 [3.42-5.75] mL/kg, P<0.01). Tidal hyperinflation was also larger at VT 12 mL/kg (0.55 [0.27-2.24] vs. 0.24 [0.18-0.83], P<0.01).
High tidal volume is a major determinant of cyclic recruitment-derecruitment in ARDS patients with diffuse attenuations.
过度膨胀和周期性募集-去募集导致呼吸机引起的肺损伤。高潮气量被认为主要通过诱导过度膨胀增加死亡率。然而，实验证据表明，潮气量（VT）也可能影响周期性募集-去募集。我们的主要目标是通过动态计算机断层扫描（CT）确定高潮气量是否会增加急性呼吸窘迫综合征（ARDS）患者的周期性募集-去募集。
我们研究了 9 例 CT 弥漫性衰减的 ARDS 患者，他们接受了包括 2 种通气模式的方案：（a）VT 6 mL/kg，呼吸频率 30/min，PEEP 9 cmH2O，（b）VT 12 mL/kg，呼吸频率 15/min，PEEP 9 cmH2O。在每个通气模式下进行 8 秒的固定横断区动态 CT。周期性募集-去募集通过吸气和呼气之间的非充气组织变化来确定，并表示为肺组织重量的%。
与 VT 6 ml/kg 相比，VT 12 ml/kg 在呼气时的非充气组织较少（分别为 40.15[35.94-56.00]和 45.31[37.95-59.32]，P<0.05）。然而，与 VT 6 mL/kg 相比，VT 12 ml/kg 增加了周期性募集-去募集（7.32[6.58-9.29]mL/kg 与 4.51[3.42-5.75]mL/kg，P<0.01）。VT 12 mL/kg 时的潮气量过度膨胀也更大（0.55[0.27-2.24]与 0.24[0.18-0.83]，P<0.01）。
弥漫性衰减的 ARDS 患者中，高潮气量是周期性募集-去募集的主要决定因素。
