Point-of-Care Ultrasound Predicts Clinical Outcomes in Patients With COVID-19

Abstract

Objectives: Point-of-care ultrasound (POCUS) detects the pulmonary manifestations of COVID-19 and may predict patient outcomes.

Methods: We conducted a prospective cohort study at four hospitals from March 2020 to January 2021 to evaluate lung POCUS and clinical outcomes of COVID-19. Inclusion criteria included adult patients hospitalized for COVID-19 who received lung POCUS with a 12-zone protocol. Each image was interpreted by two reviewers blinded to clinical outcomes. Our primary outcome was the need for intensive care unit (ICU) admission versus no ICU admission. Secondary outcomes included intubation and supplemental oxygen usage.

Results: N = 160 patients were included. Among critically ill patients, B-lines (94 vs 76%; P < .01) and consolidations (70 vs 46%; P < .01) were more common. For scans collected within 24 hours of admission (N = 101 patients), early B-lines (odds ratio [OR] 4.41 [95% confidence interval, CI: 1.71-14.30]; P < .01) or consolidations (OR 2.49 [95% CI: 1.35-4.86]; P < .01) were predictive of ICU admission. Early consolidations were associated with oxygen usage after discharge (OR 2.16 [95% CI: 1.01-4.70]; P = .047). Patients with a normal scan within 24 hours of admission were less likely to require ICU admission (OR 0.28 [95% CI: 0.09-0.75]; P < .01) or supplemental oxygen (OR 0.26 [95% CI: 0.11-0.61]; P < .01). Ultrasound findings did not dynamically change over a 28-day scanning window after symptom onset.

Conclusions: Lung POCUS findings detected within 24 hours of admission may provide expedient risk stratification for important COVID-19 clinical outcomes, including future ICU admission or need for supplemental oxygen. Conversely, a normal scan within 24 hours of admission appears protective. POCUS findings appeared stable over a 28-day scanning window, suggesting that these findings, regardless of their timing, may have clinical implications.

Keywords: COVID-19; ICU; POCUS; mortality; outcomes; ultrasound.

Figure 1

Scanning protocol and lung ultrasound findings in COVID‐19 patients. This study utilized a 12‐zone protocol (6 zones per each hemithorax), which we have previously described., If a 12‐zone protocol could not be obtained, then an 8‐zone protocol (which excludes zones 5–6) was obtained. This figure contains an overview of the observed ultrasound findings based on previously described terminology., Common pathological findings with COVID‐19 on ultrasound include B‐lines, consolidations, and patchy A‐lines. B‐lines are vertically oriented hyperechoic artifacts that arise from the pleura. They are caused by thickened interlobular septa due to alveolar–interstitial disorders, such as pneumonia, cardiogenic edema, acute respiratory distress syndrome, or abnormal collagen deposition (eg, idiopathic pulmonary fibrosis). Consolidations manifest as dense, echogenic lung parenchyma with occasional air bronchograms. Consolidations may affect more distal airways first (resulting in sub‐pleural consolidations) and eventually result in lobar collapse with more substantial involvement (eg, translobar consolidation). A‐lines represent a reverberation artifact arising from the pleura and represent normal lung parenchyma. AAL, anterior axillary line; PAL, posterior axillary line; ISM, inferior scapular margin.

Figure 2

Persistence of lung ultrasound findings over time. Lung findings were stratified by days from symptom onset to the ultrasound scan into quartiles (0–6 days, 7–13 days, 14–20 days, and 21–28 days). There was no significant difference in the frequency of findings across the time periods or when comparing early (0–6 days) versus late (21–28 days) scanning periods.