Prospective Longitudinal Evaluation of Point-of-Care Lung Ultrasound in Critically Ill Patients With Severe COVID-19 Pneumonia

Abstract

Objectives: To perform a prospective longitudinal analysis of lung ultrasound findings in critically ill patients with coronavirus disease 2019 (COVID-19).

Methods: Eighty-nine intensive care unit (ICU) patients with confirmed COVID-19 were prospectively enrolled and tracked. Point-of-care ultrasound (POCUS) examinations were performed with phased array, convex, and linear transducers using portable machines. The thorax was scanned in 12 lung areas: anterior, lateral, and posterior (superior/inferior) bilaterally. Lower limbs were scanned for deep venous thrombosis and chest computed tomographic angiography was performed to exclude suspected pulmonary embolism (PE). Follow-up POCUS was performed weekly and before hospital discharge.

Results: Patients were predominantly male (84.2%), with a median age of 43 years. The median duration of mechanical ventilation was 17 (interquartile range, 10-22) days; the ICU length of stay was 22 (interquartile range, 20.2-25.2) days; and the 28-day mortality rate was 28.1%. On ICU admission, POCUS detected bilateral irregular pleural lines (78.6%) with accompanying confluent and separate B-lines (100%), variable consolidations (61.7%), and pleural and cardiac effusions (22.4% and 13.4%, respectively). These findings appeared to signify a late stage of COVID-19 pneumonia. Deep venous thrombosis was identified in 16.8% of patients, whereas chest computed tomographic angiography confirmed PE in 24.7% of patients. Five to six weeks after ICU admission, follow-up POCUS examinations detected significantly lower rates (P < .05) of lung abnormalities in survivors.

Conclusions: Point-of-care ultrasound depicted B-lines, pleural line irregularities, and variable consolidations. Lung ultrasound findings were significantly decreased by ICU discharge, suggesting persistent but slow resolution of at least some COVID-19 lung lesions. Although POCUS identified deep venous thrombosis in less than 20% of patients at the bedside, nearly one-fourth of all patients were found to have computed tomography-proven PE.

Keywords: COVID-19 pneumonia; acute respiratory failure; chest computed tomography; point-of-care lung ultrasound; pulmonary embolism.

Figure 1

Scanning with different transducers in 4 critically ill patients with COVID‐19: irregular pleural line with associated subpleural consolidation, B‐lines, and hyperechoic parenchymal consolidation in the posterior‐inferior area of the left lung depicted by a phased array (2.5‐MHz) transducer (A); beam line artifact in the inferior‐anterior area of the right lung depicted by a linear (15‐MHz) transducer (B); beam line artifact in the lateral‐inferior area of the right lung depicted by a phase array (2.5‐MHz) transducer (C); and beam line artifact and hyperechoic consolidations depicted by a convex (3.5‐MHz) transducer in the inferior‐anterior area of the right lung (D, panoramic view integrating 3 intercostal spaces).

Figure 2

Scanning with a linear high‐frequency (12‐MHz) transducer in the superior‐anterior area of the left lung in a critically ill patient with COVID‐19 depicting (white arrows) irregularities of the pleural line with associated B‐lines (A) and subpleural consolidations (B).

Figure 3

Confluent (A) and separate (B) B‐lines detected by a phased array (2.5‐MHz) transducer in the inferior‐anterior area of the right lung in a critically ill patient with COVID‐19.

Figure 4

Panoramic views integrating 3 intercostal spaces by a convex (3.5‐MHz) transducer depicting separate B‐lines in the inferior‐anterior area of the right lung (A) and beam line artifacts with hyperechoic consolidations in the inferior‐posterior area of the right lung (B) in 4 critically ill patients with COVID‐19.

Figure 5

Bright hyperechoic (starry sky) consolidation and pleural effusion depicted by a convex (3.5‐MHz) transducer in the superior‐lateral area of the right lung (A) and lung hepatization consolidation floating in a large pleural effusion in the inferior‐lateral area of the right lung depicted by a phases array (2.5‐MHz) transducer (B) in 2 critically ill patients with COVID‐19.

Figure 6

Zoomed‐in image of a bright hyperechoic (starry sky) consolidation and associated pleural effusion in the inferior‐posterior area of the right lung depicted by a phased array (2.5‐MHz) transducer in a critically ill patient with COVID‐19.

Figure 7

Small pneumothorax (white arrow indicates lung point) detected by a linear (15‐MHz) transducer in the inferior‐anterior area of the right lung in a critically ill patient with COVID‐19.

Figure 8

Contrast chest CT scans depicting (red arrowheads) upper and middle segmental right pulmonary artery nonobstructive emboli (A) and tiny filling defects suggestive of microemboli of the distal subsegmental branches of the right pulmonary artery (B) in 2 critically patients with COVID‐19.

Figure 9

Evolution of fulminant COVID‐19 pneumonia in a 50‐year‐old diabetic patient. Panoramic views depicted by a convex (3.5‐MHz) transducer scanning the superior‐anterior area of the right lung: normal lung aeration pattern (A‐lines; A, white arrow) while the patient was receiving an HFNC (day 1); appearance of the beam line artifact (B and C, white chevrons at the interface with the normal lung parenchyma) while the patient was receiving an HFNC (day 2); appearance of subpleural consolidation (D, white star) and separate B‐lines derived from thickened pleural lines while the patient was intubated and receiving mechanical ventilation (day 4); and pleural line irregularities with hyperechoic consolidations and separate B‐lines while the patient was receiving mechanical ventilation (day 7; E).

Figure 10

Scanning with a convex (3.5‐MHz) transducer in the inferior‐posterior right lung area depicting hyperechoic consolidations (A, white chevron) and in the left inferior‐lateral lung area depicting hyperechoic consolidation (white arrow; B, starry sky) with mixed features of lung hepatization and a pleural effusion (white star indicates heart, seen moving on real time scanning).

Figure 11

Scanning with a convex (3.5‐MHz) transducer in the inferior‐posterior right lung area depicting hyperechoic lung consolidations (A, white chevron) on day 4 after intubation in a critically ill patient with COVID‐19 and in the inferior‐lateral right lung area depicting hepatized lung with mixed air bronchograms (B, white arrowhead) adjacent to the liver (white arrow).