For adults with ARDS on protective ventilation, what is the recommended tidal volume based on ideal body weight?

• A. About 8 mL/kg IBW (range 6–10)
• B. About 6 mL/kg IBW (range 4–8)
• C. About 10 mL/kg IBW (range 8–12)
• D. About 2 mL/kg IBW (range 1–3)

Answer: (B)

In ARDS managed with protective ventilation, the goal is to limit lung stretch by using a low tidal volume based on ideal body weight. The commonly recommended target is about 6 mL per kilogram of ideal body weight, with an acceptable range of roughly 4–8 mL/kg IBW. This approach reduces volutrauma and ventilator-induced lung injury while still allowing adequate ventilation when plateau pressures are kept around or below 30 cm H2O, with PEEP adjustments to support oxygenation. Higher tidal volumes, such as around 8 or 10 mL/kg, overly distend normal and injured lung regions and have been linked to worse outcomes in ARDS. A tidal volume around 2 mL/kg would provide insufficient ventilation and can lead to dangerous hypercapnia and atelectasis.