In a patient with respiratory distress, how should PEEP be adjusted in the case of ARDS?

In the management of Acute Respiratory Distress Syndrome (ARDS), increasing the positive end-expiratory pressure (PEEP) can be beneficial to improve oxygenation and recruit collapsed alveoli. The rationale for maintaining or increasing PEEP in ARDS is based on the pathophysiology of the condition, where alveolar collapse leads to ventilation-perfusion mismatches and impaired gas exchange.

Increasing PEEP to a setting like 10 cm H2O can help keep the alveoli open during expiration, which allows for better gas exchange and reduces shunting. It also decreases the work of breathing and improves lung compliance. The goal is to optimize oxygenation while minimizing the risk of ventilator-induced lung injury. High PEEP levels can help improve the functional residual capacity (FRC) but must be monitored closely to prevent detrimental effects such as hemodynamic instability.

Choosing not to use PEEP, or setting it too low, can result in worsening hypoxemia and ventilation-perfusion mismatches, which is why options involving a decrease or elimination of PEEP would not be appropriate for a patient with ARDS.