Direct evidence of small airway closure in acute respiratory distress syndrome

Airway closure is thought to play an important role in acute respiratory distress syndrome (ARDS).

Airway closure has been imaged for the first time in an ARDS model by synchrotron phase contrast imaging providing direct evidence of this phenomenon.

ARDS is an acute inflammatory lung condition associated with high permeability oedema, surfactant dysfunction and widespread collapse of pulmonary alveoli, called atelectasis, which leads to decreased lung compliance and volume [1]. Clinicians have long suspected that the collapsibility of small airways is increased in this clinical syndrome, causing atelectasis [2,3]. While patients invariably require mechanical ventilation to survive, this life support measure can worsen lung injury due to exaggerated stress and strain applied to the tissue, which is magnified by mechanical inhomogeneity of lung tissue and atelectasis. Efforts to develop ventilation strategies that protect the lung, critically depend on our understanding of the mechanical behaviour of lung tissue and airways at the microscale. However, traditional computed tomography studies have not been able to clearly identify airway closure as a cause of atelectasis, due to their limited spatial resolution. To better identify the mechanisms involved in airway closure, it is necessary to use approaches that allow the study of individual airways. Here, the same individual small airways in intact lungs of anesthetised and mechanically ventilated rabbits with ARDS was studied using high resolution synchrotron phase-contrast computed tomography at beamline ID17.

>Read more on the European Synchrotron (ESRF) website