In ARDS, what does the term 'recruitability' refer to?

The term 'recruitability' in the context of Acute Respiratory Distress Syndrome (ARDS) specifically refers to the potential of collapsed alveoli to reopen with the application of positive pressure. In ARDS, lung injury leads to the collapse of alveoli, which decreases overall lung compliance and impairs gas exchange. When patients are placed on mechanical ventilation, the application of positive end-expiratory pressure (PEEP) can help reinflate these collapsed alveoli, improving ventilation and oxygenation.

The concept of recruitability is crucial, as it indicates the lungs' capacity to regain function and improve oxygenation with appropriate mechanical ventilation strategies. Effective recruitment of collapsed alveoli can significantly enhance the recruitment of functional lung units, thereby reducing shunting and improving overall gas exchange in patients with ARDS.

The other options address different aspects of respiratory management but do not accurately define recruitability within the context of ARDS. For example, while increasing respiratory rate and tidal volume can be part of a ventilation strategy, they do not specifically relate to the reopening of collapsed alveoli. Additionally, responsiveness to corticosteroid treatment pertains to the inflammatory component of ARDS rather than the mechanical aspect of lung recruitability.