American Board of Internal Medicine (ABIM) Certification Practice Exam

For a patient with ARDS, what is the recommended tidal volume setting based on ideal body weight?

1. 8 mL/kg

2. 6 mL/kg

3. 4 mL/kg

4. 10 mL/kg

The correct answer is: 6 mL/kg

In the management of patients with Acute Respiratory Distress Syndrome (ARDS), the recommended tidal volume setting is based on the patient's ideal body weight (IBW) and is typically set at 6 mL per kg of IBW. This approach is grounded in evidence that using lower tidal volumes can reduce ventilator-induced lung injury and improve clinical outcomes. By adhering to this recommendation, clinicians aim to minimize barotrauma and volutrauma while optimizing oxygenation and preventing exacerbation of lung injury. The use of 6 mL/kg is part of a lung-protective ventilation strategy that encourages alveolar recruitment while limiting overdistension of the lungs, which is crucial for patients with ARDS, who already have compromised lung function. This strategy is supported by various studies showing a reduction in mortality in patients with ARDS when lower tidal volumes are utilized compared to traditional higher tidal volumes. Choosing a tidal volume that is too high, such as 8 mL/kg, 10 mL/kg, or even lower than 6 mL/kg can lead to negative consequences such as increased peak airway pressures and risk of alveolar damage, which would counteract the goals of protective mechanical ventilation. Thus, the selection of 6 mL/kg