Lung Ultrasound for Identification of Patients Requiring Invasive Mechanical Ventilation in COVID‐19

OBJECTIVES: Indication for invasive mechanical ventilation in COVID‐19 pneumonia has been a major challenge. This study aimed to evaluate if lung ultrasound (LUS) can assist identification of requirement of invasive mechanical ventilation in moderate to severe COVID‐19 pneumonia. MATERIALS AND METHODS: Between April 23 and November 12, 2020, hospitalized patients with moderate to severe COVID‐19 (oxygen demand ≥4 L/min) were included consecutively. Lung ultrasound was performed daily until invasive mechanical ventilation (IMV‐group) or spontaneous recovery (non‐IMV‐group). Clinical parameters and lung ultrasound findings were compared between groups, at intubation (IMV‐group) and highest oxygen demand (non‐IMV‐group). A reference group with oxygen demand <4 L/min was examined at hospital admission. RESULTS: Altogether 72 patients were included: 50 study patients (IMV‐group, n = 23; non‐IMV‐group, n = 27) and 22 reference patients. LUS‐score correlated to oxygen demand (SpO(2)/FiO(2)‐ratio) (r = 0.728; p < .0001) and was higher in the IMV‐group compared to the non‐IMV‐group (20.0 versus 18.0; p = .026). Based on receiver operating characteristic analysis, a LUS‐score of 19.5 was identified as cut‐off for requirement of invasive mechanical ventilation (area under the curve 0.68; sensitivity 56%, specificity 74%). In 6 patients, LUS identified critical coexisting conditions. Respiratory rate and oxygenation index ((SpO(2)/FiO(2))/respiratory rate) ≥4.88 identified no requirement of invasive mechanical ventilation with a positive predictive value of 87% and negative predictive value of 100%. CONCLUSIONS: LUS‐score had only a moderate diagnostic value for requirement of invasive mechanical ventilation in moderate to severe COVID‐19. However, LUS proved valuable as complement to respiratory parameters in guidance of disease severity and identifying critical coexisting conditions.