The Role of Lung Ultrasound Monitoring in Early Detection of Ventilator-Associated Pneumonia in COVID-19 Patients: A Retrospective Observational Study

Abstract

Specific lung ultrasound signs combined with clinical parameters allow for early diagnosis of ventilator-associated pneumonia in the general ICU population. This retrospective cohort study aimed to determine the accuracy of lung ultrasound monitoring for ventilator-associated pneumonia diagnosis in COVID-19 patients. Clinical (i.e., clinical pulmonary infection score) and ultrasound (i.e., presence of consolidation and a dynamic linear–arborescent air bronchogram, lung ultrasound score, ventilator-associated lung ultrasound score) data were collected on the day of the microbiological sample (pneumonia-day) and 48 h before (baseline) on 55 bronchoalveolar lavages of 33 mechanically-ventilated COVID-19 patients who were monitored daily with lung ultrasounds. A total of 26 samples in 23 patients were positive for ventilator-associated pneumonia (pneumonia cases). The onset of a dynamic linear–arborescent air bronchogram was 100% specific for ventilator-associated pneumonia. The ventilator-associated lung ultrasound score was higher in pneumonia-cases (2.5 (IQR 1.0 to 4.0) vs. 1.0 (IQR 1.0 to 1.0); p < 0.001); the lung ultrasound score increased from baseline in pneumonia-cases only (3.5 (IQR 2.0 to 6.0) vs. −1.0 (IQR −2.0 to 1.0); p = 0.0001). The area under the curve for clinical parameters, ventilator-associated pneumonia lung ultrasound score, and lung ultrasound score variations were 0.472, 0.716, and 0.800, respectively. A newly appeared dynamic linear–arborescent air bronchogram is highly specific for ventilator-associated pneumonia in COVID-19 patients. A high ventilator-associated pneumonia lung ultrasound score (or an increase in the lung ultrasound score) orients to ventilator-associated pneumonia.

Lung ultrasound training: how short is too short? observational study on the effects of a focused theoretical training for novice learners

“…Moreover, we didn’t explore if images’ recognition skills persisted at different time intervals (e.g., after 1 day, 1 week, 1 month). A limited number of basic signs were tested (B-lines and pleural movements), thus excluding other significant lung ultrasound findings as consolidations [ 38 ] or air-bronchogram within consolidations [ 39 ] that help in the diagnosis of pneumonia in the critically ill. Finally, a reference standard for the test was not available (i.e., the total score reported by a sample of experts in the field); however, the clips used for the tests were good quality images, with findings that are considered basic [ 40 ], so the percentage of correct answers by a pool of experts was expected to be near to 100%.…”

Lung Ultrasound in Critical Care and Emergency Medicine: Clinical Review

“…In intensive care patients under mechanical ventilation, where more intricated mechanisms may lead to a complete loss of aeration, mainly in the posterior fields, the presence of a tissue-like pattern is highly non-specific for ventilator-associated pneumonia; in this context, the interpretation of the air bronchogram is an additional value. A dynamic linear/arborescent air bronchogram within a consolidation has been demonstrated to be highly specific for a VAP [ 59 , 60 ]. A dynamic air bronchogram rules out obstructive atelectasis, which are instead characterized by a static bronchogram (in the initial phase) or by the absence of any air bronchograms (no air is present neither in the small airways) [ 61 ].…”

“…LUS has also been confirmed to be a valuable tool for the bedside identification of pulmonary overinfections in COVID-19 patients already admitted to ICUs for pneumonia and ARDS. In a retrospective observational study, dynamic linear/arborescent air bronchograms within lobar/hemilobar consolidations were demonstrated to have a very high specificity [ 60 ]. In patients monitored by a daily assessment of a lung ultrasound score, an increase in the LUS score should raise the doubt of an overinfection [ 4 , 64 ].…”