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

Point-of-care ultrasound (POCUS) can detect the pulmonary manifestations of COVID-19 and predict patient outcomes, according to a new study.

These findings were from a prospective cohort study conducted by researchers of Stanford University (Stanford, CA, USA) 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. The study’s primary outcome was the need for intensive care unit (ICU) admission versus no ICU admission. Secondary outcomes included intubation and supplemental oxygen usage.

POCUS has garnered substantial interest as a potential modality to expediently diagnose COVID-19 and its complications. POCUS devices are cheaper than traditional imaging equipment, such as X-ray or computed tomography (CT) machines, which makes POCUS ideal for surge scenarios and resource-limited settings. Since providers using POCUS are concomitantly at the bedside assessing patients, POCUS permits an immediate and augmented evaluation of the patient. It can reduce personal protective equipment usage by radiology technicians as well as the need to decontaminate larger radiographic equipment. POCUS has also been successfully used in the diagnosis and management of COVID-19. Previously described pulmonary manifestations of COVID-19 include pulmonary edema, lung consolidation, and pleural-line irregularities. POCUS can diagnose these pathological states with similar accuracy to CT and with higher sensitivity than X-ray.

Although lung ultrasound abnormalities are more common in patients who experience adverse outcomes with COVID-19, few studies have examined whether scans performed early in the hospitalization can provide meaningful risk stratification. Furthermore, few scoring tools predict the need for oxygen on discharge, which represents a limited resource in many settings. In the latest study, the researchers examined whether early pulmonary POCUS findings correlate with important clinical outcomes, such as intensive care admission or need for supplemental oxygen. They also examined whether these findings, if detected early, are predictive of future clinical outcomes in the subsequent hospital course or after discharge.

In this prospective cohort study conducted at four medical centers of patients hospitalized with COVID-19, the researchers found that lung ultrasounds collected within 24 hours of emergency department triage were predictive of important clinical outcomes in the subsequent hospital course, including ICU admission, intubation, supplemental oxygen usage, and the need for oxygen at discharge. Ultrasound findings associated with an adverse clinical course included B-lines and consolidations (particularly in the anterior and lateral lung fields), while a normal ultrasound on triage was protective against adverse outcomes. Notably, ultrasound findings did not dynamically change over a 28-day window after symptom onset, suggesting that the presence of B-lines or consolidations, regardless of when they are detected, may be important clinical predictors.

Previous investigations have demonstrated that lung POCUS findings (such as B-lines or consolidations) are associated with critical illness and intubation for COVID-19. The new study expands on these observations by demonstrating that scans collected within 24 hours of ED triage may predict outcomes for the entire hospital course, including future supplemental oxygen usage and the need for oxygen on discharge. This information may substantially aid frontline providers in resource-limited settings experiencing patient surges. In such scenarios, POCUS could augment admission or discharge decisions for providers. More broadly, POCUS could represent one of several tools to identify patients at-risk for adverse outcomes. Other authors have demonstrated the utility of laboratory tests (eg, ferritin, c-reactive protein) or radiographic findings for risk stratification. POCUS may have potential advantages over these other methods in that it is more expedient, low cost and does not expose the patient to ionizing radiation. Future studies are needed to directly compare POCUS with other scoring systems that utilize laboratory or radiological findings.

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