Lung ultrasound and computed tomography to monitor COVID-19 pneumonia in critically ill patients: a two-center prospective cohort study

Abstract

Background Lung ultrasound can adequately monitor disease severity in pneumonia and acute respiratory distress syndrome. We hypothesize lung ultrasound can adequately monitor COVID-19 pneumonia in critically ill patients. Methods Adult patients with COVID-19 pneumonia admitted to the intensive care unit of two academic hospitals who underwent a 12-zone lung ultrasound and a chest CT examination were included. Baseline characteristics, and outcomes including composite endpoint death or ICU stay > 30 days were recorded. Lung ultrasound and CT images were quantified as a lung ultrasound score involvement index (LUSI) and CT severity involvement index (CTSI). Primary outcome was the correlation, agreement, and concordance between LUSI and CTSI. Secondary outcome was the association of LUSI and CTSI with the composite endpoints. Results We included 55 ultrasound examinations in 34 patients, which were 88% were male, with a mean age of 63 years and mean P/F ratio of 151. The correlation between LUSI and CTSI was strong (r = 0.795), with an overall 15% bias, and limits of agreement ranging − 40 to 9.7. Concordance between changes in sequentially measured LUSI and CTSI was 81%. In the univariate model, high involvement on LUSI and CTSI were associated with a composite endpoint. In the multivariate model, LUSI was the only remaining independent predictor. Conclusions Lung ultrasound can be used as an alternative for chest CT in monitoring COVID-19 pneumonia in critically ill patients as it can quantify pulmonary involvement, register changes over the course of the disease, and predict death or ICU stay > 30 days. Trial registration: NTR, NL8584. Registered 01 May 2020—retrospectively registered, https://www.trialregister.nl/trial/8584

Comparison of two different lung ultrasound imaging protocols in COVID-19 pneumonia

“…They reported that the LUS findings they reached in their study included pleural line and B line abnormalities, similar to the results of other studies [19]. In the study using the same number of examination zones in intensive care patients, the correlation between LUS scores and CT scores was 0.87, and it was found that there was a good degree of agreement [20]. In addition, they reported that the LUS, in which six zones were examined, was able to yield similar results to the LUS, in which twelvezones were evaluated.Despite the fact that the results needed to be confirmed, they stated that the results were similar to the literature data, and the results of the studies using the BLUE protocol [20].…”

“…In the study using the same number of examination zones in intensive care patients, the correlation between LUS scores and CT scores was 0.87, and it was found that there was a good degree of agreement [20]. In addition, they reported that the LUS, in which six zones were examined, was able to yield similar results to the LUS, in which twelvezones were evaluated.Despite the fact that the results needed to be confirmed, they stated that the results were similar to the literature data, and the results of the studies using the BLUE protocol [20]. Since there were studies in the literature using different methods of examination, Soldati et al created a LUS protocol with the aim of developing international standardization.…”

Determining the optimal number of lung ultrasound zones to monitor COVID-19 patients: can we keep it ultra-short and ultra-simple?

“…First, whether the reference standard accurately represents total pulmonary involvement is uncertain. In fact, previous research has shown equivalence of both 6- or 12-zone protocols compared to gold standard chest computed tomography (CT) [ 3 , 4 ]. Second, the 14-zone protocol’s overrepresentation of posterior zones (43%) constitutes a scan-location bias, which is problematic when examining disease with gravity-dependent distribution.…”

“…Reference test was a 12-zone LUS protocol which has shown to have monitoring equivalence to CT and index test was a 6-zone LUS protocol (Fig. 1 A) [ 4 ]. Each LUS zone was scored from 0 (A-pattern) to 3 (consolidation).…”

Lung ultrasound as a predictor of mortality of patients with COVID-19

“…(5) Several studies have shown that LUS can detect interstitial disease, subpleural consolidations, and respiratory distress of any aetiology, with sensitivity and specificity superior to chest radiography and comparable to CT. (6)(7)(8) Indeed, LUS has already been recommended in past viral pandemics (9) and growing evidence demonstrates its effectiveness in patients with COVID-19, (10) which allows identifying the degree of lung involvement, its course, and the possible association between the initial lung involvement and its prognosis. (11)(12)(13)(14)(15) Our objective was to evaluate the performance of LUS through the lung ultrasound score (LUS score) to determine the severity of pneumonia and the short-term outcomes of patients with COVID-19 admitted to the intensive care unit. We hypothesize that the Lung Ultrasound Score (LUS) correlates with clinical evolution and predicts mortality in critically ill COVID-19 pneumonia patients.…”