Do Serial Lung Ultrasound Scores Predict Prolonged Mechanical Ventilation in Patients With Severe COVID-19? A Single-centre Retrospective Cohort Study

Abstract

Background: Some patients with severe coronavirus disease (COVID-19) who present with fibrosis on computed tomography (CT) require prolonged mechanical ventilation (PMV). Lung ultrasound (LUS), a rapid, bedside test, has been reported to have findings consistent with those of CT. Thus, this study aimed to assess whether serial LUS scores could predict PMV or successful extubation in severe COVID-19 patients.Methods: LUS was performed for 20 consecutive severe COVID-19 patients at three time points: admission (day 1), after 48 h (day 3), and seventh-day follow-up (day 7). We compared the LUS score with the results of chest X-rays and laboratory tests at three time points. Moreover, we assessed LUS score to determine the inter-rater reliability (IRR) of the results among examiners.Results: While there were no significant differences in mortality in each PMV and successful extubation groups, there were significant differences in LUS scores on day 3 and day 7; XP score on day 7; and P/F ratio on day 7 in the PMV group (p<0.05). There were significant differences in LUS scores on days 3 and 7, C-reactive protein (CRP) levels on day 7, and P/F ratio on day 7 in the successful extubation group (p<0.05). The areas under the curves (AUCs) of LUS score on days 3 and 7, XP score on day 7, and P/F ratio were 0.88, 0.98, 0.77, and 0.80, respectively in the PMV group; and the AUCs of LUS score on days 3 and 7, CRP levels on day 7, and P/F ratio 0.79, 0.90, 0.82, and 0.79, respectively, in the successful extubation group. Variations in serial LUS scores exhibited significant differences between the groups. The serial LUS score on day 7 was higher than that on day 1 in the PMV group but lower in the successful extubation group (p<0.05). However, there was slight IRR agreement in the LUS score changes on days 1 to 7 (κ= 0.15 [95% CI: 0-0.31]). Conclusions: The serial LUS score of severe COVID-19 patients could predicted PMV and successful extubation. To overcome IRR disagreement, the automatic ultrasound judgement, such as deep learning, would be needed.