Macklin effect on baseline chest CT scan accurately predicts barotrauma in COVID-19 patients

Abstract

Purpose: To validate the role of Macklin effect on chest CT imaging in predicting subsequent occurrence of pneumomediastinum/pneumothorax (PMD/PNX) in COVID-19 patients.

Materials and methods: This is an observational, case-control study. Consecutive COVID-19 patients who underwent chest CT scan at hospital admission during the study time period (October 1st, 2020-April 31st, 2021) were identified. Macklin effect accuracy for prediction of spontaneous barotrauma was measured in terms of sensitivity, specificity, positive (PPV) and negative predictive values (NPV).

Results: Overall, 981 COVID-19 patients underwent chest CT scan at hospital arrival during the study time period; 698 patients had radiological signs of interstitial pneumonia and were considered for further evaluation. Among these, Macklin effect was found in 33 (4.7%), including all 32 patients who suffered from barotrauma lately during hospital stay (true positive rate: 96.9%); only 1/33 with Macklin effect did not develop barotrauma (false positive rate: 3.1%). No barotrauma event was recorded in patients without Macklin effect on baseline chest CT scan. Macklin effect yielded a sensitivity of 100% (95% CI: 89.1-100), a specificity of 99.85% (95% CI: 99.2-100), a PPV of 96.7% (95% CI: 80.8-99.5), a NPV of 100% and an accuracy of 99.8% (95% CI: 99.2-100) in predicting PMD/PNX, with a mean advance of 3.2 ± 2.5 days. Moreover, all Macklin-positive patients developed ARDS requiring ICU admission and, in 90.1% of cases, invasive mechanical ventilation.

Conclusions: Macklin effect has high accuracy in predicting PMD/PNX in COVID-19 patients; it is also an excellent predictor of disease severity.

Keywords: Acute respiratory distress syndrome; Barotrauma; Computed tomography; Intensive care; Mechanical ventilation; Pneumomediastinum; Pneumothorax.

Fig. 1

Macklin effect in a COVID-19 patient. Lung parenchyma windowed CT images demonstrate [a] a crescent collection of air contiguous to the middle lobar bronchovascular sheath as well as interstitial emphysema in the left upper lobe, both representing Macklin effect (red arrows). Seven days later [b], pneumomediastinum occurred. . (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

Lung parenchyma window axial (a) and coronal (b) CT scans of patient suffering from SARS-CoV-2 infection, subjected to invasive mechanics ventilation, show: central Macklin effect (black arrow) in association with pneumomediastinum (white arrow), pneumothorax (white arrow heads), subcutaneous emphysema (black star) and pneumoperitoneum (black arrow head).

Fig. 3

Inclusion/exclusion flowchart.