Innovations in bedside imaging technologies such as electrical impedance tomography readily allow clinicians to determine the regional distributions of V and Q, as well as the adequacy of their matching, providing new insights into the phenotyping, prognostication, and clinical management of patients with ARDS. Beyond its impact on gas exchange, V/ Q mismatch is a predictor of adverse outcomes in patients with ARDS more recently, its role in ventilation-induced lung injury and worsening lung edema has been described. The perfusion of collapsed or consolidated lung units gives rise to intrapulmonary shunting and arterial hypoxemia, whereas the ventilation of non-perfused lung zones increases physiological dead-space, which potentially necessitates increased ventilation to avoid hypercapnia.

In patients with ARDS, disturbances in the physiological matching of alveolar ventilation (V) and pulmonary perfusion (Q) ( V/ Q mismatch) are a hallmark derangement. It is being increasingly demonstrated that the improvement of outcomes requires a tailored, individualized approach to therapy, guided by a detailed understanding of each patient’s pathophysiology.

Acute respiratory distress syndrome (ARDS) remains an important clinical challenge with a mortality rate of 35–45%.

Intrapulmonary shunting vs dead space