Lung imaging in critically ill patients under mechanical ventilation

Patients with respiratory failure commonly require invasive mechanical ventilation at the intensive care unit. Lung imaging is crucial for monitoring of these patients and detection of pulmonary complications. The first part of the thesis describes empirical studies in lung ultrasound that were performed in invasively ventilated patients. We evaluated the difference in estimating lung aeration between a linear and sector array ultrasound probe and compared aeration estimation between lung ultrasound and computed tomography. The second part of the thesis focusses on lung imaging in patients with the acute respiratory distress syndrome (ARDS). The thesis describes the development and external validation of two lung ultrasound methods: (1) a lung ultrasound method for diagnosis of ARDS and (2) a lung ultrasound method that can classify patients with ARDS as having ‘focal’ or ‘non-focal’ lung morphology. Further, quantitative analysis of computed tomography scans at two levels of positive end-expiratory pressure was performed to assess lung re-aeration in patients with COVID-19 related ARDS. We thereafter assessed the relation between lung recruitability as measured with computed tomography with pulmonary biomarkers that are representative of multiple pathways in the development of ARDS.