Given the ventilated settings of a patient, what is the appropriate action if pulmonary shunting is observed?

Increasing PEEP (Positive End-Expiratory Pressure) is a suitable action when pulmonary shunting is observed. Pulmonary shunting occurs when blood passes through the lungs without participating in gas exchange effectively, leading to inadequate oxygenation despite potentially high FiO2 levels.

By increasing PEEP, you enhance recruitment of collapsed or fluid-filled alveoli, improving ventilation-perfusion (V/Q) matching and facilitating better oxygenation. This can improve the functional residual capacity of the lungs and help to open up collapsed areas, effectively reducing shunting. Optimal PEEP settings help to improve oxygenation and support overall respiratory function in critically ill patients.

While increasing FiO2 is another common response, it may not be as effective alone if significant shunting is present. The use of bronchodilators like beta agonists may provide symptomatic relief in certain conditions such as asthma or COPD but do not directly address pulmonary shunting. Similarly, adding pressure support can assist with breathing but may not mitigate the shunting issue effectively.