In patients with acute respiratory distress syndrome (ARDS), what is the recommended tidal volume to avoid lung overdistension?

In managing patients with acute respiratory distress syndrome (ARDS), the goal is to minimize further lung injury while ensuring adequate ventilation. The recommended tidal volume for patients with ARDS is typically 6 mL/kg of predicted body weight. Using a lower tidal volume helps prevent lung overdistension and reduces the risk of barotrauma and volutrauma, which can exacerbate lung injury.

The rationale behind this is based on the understanding that ARDS is characterized by stiff, inflamed lungs that can be further damaged by the application of high tidal volumes. A strategy of lung-protective ventilation, which includes using low tidal volumes, has been shown to improve outcomes in ARDS patients.

Higher tidal volumes, such as those presented in other options, increase the risk of overdistending already compromised alveoli and can worsen ventilation-perfusion mismatch, leading to poorer oxygenation and potential respiratory failure. Therefore, the choice of 6 mL/kg as the tidal volume helps to balance the need for adequate gas exchange while minimizing the risks associated with mechanical ventilation in the context of ARDS.