Department of Medicine and Surgery, University of Milan-Bicocca, via Cadore 48, 20900, Monza, Italy; Department of Emergency and Intensive Care, San Gerardo Hospital, via Giovanni Battista Pergolesi 33, 20900, Monza, Italy.
Department of Medical Physiopathology and Transplants, University of Milan, Via Festa del Perdono 7, 20122, Milano, Italy.
Respir Physiol Neurobiol. 2022 Feb;296:103807. doi: 10.1016/j.resp.2021.103807. Epub 2021 Oct 29.
The exhaled CO signal provides guidance during cardiopulmonary resuscitation. The Airway opening index (AOI) has been recently used to quantify chest-compression (CC) induced expired CO oscillations. We aimed to determine whether levels of intrathoracic pressures developed during CC or parameters related to lung structure may affect AOI.
Secondary analysis of a randomized animal study (n = 12) in a porcine model of cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) during ambulance transport. Animals were randomized to 18-min of manual or mechanical CCs. Changes in AOI and right atrial pressure (ΔRAP) were recorded during CCs in animals undergoing manual (n = 6) or mechanical (n = 6) CCs. Lung CT scan and measurement of the respiratory system compliance (Cpl,rs) were performed immediately after return of spontaneous circulation.
Animals undergoing mechanical CCs had a lower AOI compared to animals treated with manual CCs (p < 0.001). AOI negatively correlated with the swings of intrathoracic pressure, as measured by the change in ΔRAP (ρ=-0.727, p = 0.007). AOI correlated with the lung density (ρ=-0.818, p = 0.001) and with the Cpl,rs (ρ = 0.676, p = 0.016). Animals with cardiopulmonary resuscitation associated lung edema (CRALE) (i.e. mean CT≥-500 HU) showed lower levels of AOI compared to animals without it (29 ± 12 % versus 50 ± 16 %, p = 0.025).
Animals undergoing mechanical CCs had lower levels of AOI compared to animals undergoing manual CCs. A higher swing of intrathoracic pressure during CC, a denser and a stiffer lung were associated with an impaired CO exhalation during CC as observed by a lower AOI.
呼气 CO 信号可在心肺复苏期间提供指导。气道开启指数（AOI）最近已被用于量化胸外按压（CC）诱导的呼出 CO 震荡。我们旨在确定 CC 期间产生的胸腔内压力水平或与肺结构相关的参数是否会影响 AOI。
对在救护车转运期间发生心脏骤停（CA）和心肺复苏（CPR）的猪模型中进行的一项随机动物研究（n = 12）进行二次分析。动物随机接受 18 分钟的手动或机械 CC。在接受手动（n = 6）或机械（n = 6）CC 的动物中，记录 CC 期间 AOI 和右心房压力（ΔRAP）的变化。在自主循环恢复后立即进行肺部 CT 扫描和呼吸系统顺应性（Cpl，rs）的测量。
与接受手动 CC 治疗的动物相比，接受机械 CC 的动物的 AOI 较低（p < 0.001）。AOI 与胸腔内压力波动呈负相关，如 ΔRAP 的变化所示（ρ=-0.727，p = 0.007）。AOI 与肺密度（ρ=-0.818，p = 0.001）和 Cpl，rs（ρ = 0.676，p = 0.016）相关。患有心肺复苏相关肺水肿（CRALE）的动物（即平均 CT≥-500 HU）的 AOI 水平低于没有它的动物（29 ± 12%与 50 ± 16%，p = 0.025）。
与接受手动 CC 的动物相比，接受机械 CC 的动物的 AOI 水平较低。CC 期间胸腔内压力波动较大、肺密度较高且较硬与 CO 呼气受损相关，表现为 AOI 较低。
