Quantitative CT assessment of lung injury after successful cardiopulmonary resuscitation in a porcine cardiac arrest model of different downtimes

Abstract

Background: Utilize quantitative computed tomography (QCT) to detect and evaluate the severity of lung injury after successful cardiopulmonary resuscitation (CPR) in a porcine cardiac arrest (CA) model with different downtimes. Methods: Twenty-one male domestic pigs weighing 38±3 kg were randomized into 3 groups: the sham group (n=5), the ventricular fibrillation (VF) 5 min (VF5) group (n=8), and the VF 10 min (VF10) group (n=8). VF was induced and untreated for 5 (VF5 group) or 10 (VF10 group) min before the commencement of manual CPR. Eight animals (8/8, 100%) in VF5 and 6 (6/8, 75%) in VF10 were successfully resuscitated. Chest QCT scans and arterial blood gas tests were performed at baseline and 6 h post-resuscitation. The QCT score, volume, and weight of ground-glass opacification (GGO), which was defined as poorly aerated regions with a CT value ranging from −500 Hounsfield units (HU) to −100 HU, and intense parenchymal opacification (IPO), which was defined as a non-aerated area with a CT value greater than −100 HU, were quantitatively measured. Results: Significantly shorter durations of CPR and fewer defibrillations were observed in the VF5 group compared with the VF10 group [duration of CPR: VF5 (6±0 minutes) versus VF10 (8.3±1.5 minutes), P<0.05; numbers of defibrillation: VF5 (1±0) versus VF10 (2.2±0.8), P<0.05]. Compared with the baseline or sham animals, declining gas exchanges (end-tidal CO 2 , PO 2 , oxygen index) were observed in both VF groups; however, there were no significant differences in gas exchanges between the VF groups. Compared with the VF5 group, the GGO QCT score, volume, and weight were significantly greater in the VF10 group (P=0.002, 0.001, and 0.002 respectively), while no significant differences were found in the IPO QCT score, volume, or weight between two the VF groups (P=0.354, 0.447, and 0.512 respectively). Conclusions: QCT analysis enables unique non-invasive assessments of different lung injuries (IPO and GGO lesions) that can clearly distinguish heterogeneous lesions and allow for early detection and quantitative monitoring of the severity of lung injury following CPR. QCT could provide a basis for clinical early ventilation strategy management after CPR.

Computed-Tomography as First-line Diagnostic Procedure in Patients With Out-of-Hospital Cardiac Arrest

“…In contrast, CT shows a clear advantage compared to simple chest radiography, since it allows higher quality imaging and multiplane anatomical reconstruction (33). Chest radiography underestimates life-threatening complications such as pneumothorax, especially in supine position single-plane images (12,33,34). In addition, CPR-related rib and sternal fractures are underdiagnosed by conventional chest X-ray (35).…”

Compression depth of 30 mm has similar efficacy and fewer complications versus 50 mm during mechanical chest compression with miniaturized chest compressor in a porcine model of cardiac arrest

“…In the current study, we utilized QCT to assess the CPR-associated complications and severity of lung injuries. Our previous study successfully characterized that the non-invasive property of chest QCT could efficaciously differentiate various lung lesions, allowing for quantitative and rapid assessment of chest and lung injuries (IPO and GGO scores) following CPR (15). As expected, GGO and IPO were detected in all animals at ROSC 6 h. IPO is considered to be the manifestation of physical injury following CPR and is characterized by remarkable increased lung opacity on the QCT images.…”

“…J Thorac Dis 2021 | https://dx.doi.org/10.21037/jtd-21-812 0.75 mm slice width, no intervals, field of view 255 mm ×255 mm, and B70s kernel for reconstruction. The whole procedure of the QCT took about 4.9 s. Lung injuries QCT scores, including GGO and IPO, were assessed independently by 2 experienced thoracic radiologists according to established protocol (15,16). Settings optimized for lung evaluation were window level −600 HU, window width 1,200 Hounsfield units (HU).…”

Acute Lung Injury after Cardiopulmonary Resuscitation: A Narrative Review

“…The radiological findings were consolidation and ground-glass opacity in 93% of the patients, and in almost all the cases, i.e., 95%, lung contusions were present in the dependent regions [29]. Ground-glass opacities further confirmed by histopathological findings were then reported and quantified by CT scan analysis in porcine models of CPR [30]. The variety and incidence of CPR-related lung injuries revealed by chest CT scan are summarized in Table 2.…”

“…Areas of lung consolidation with serofibrinous exudate, hemorrhage, and inflammatory cells were also described. Moreover, alveolar collapse, alveolar distension, intra-alveolar and peri-bronchiolar hemorrhage were frequently observed [16,30,31]. Serious thoracic and lung injuries are also thought to adversely affect hemodynamics during CPR itself.…”