In ARDS protective ventilation, the tidal volume per kilogram of ideal body weight is typically kept to which range?

• A. 2–4 mL/kg IBW
• B. 4–8 mL/kg IBW
• C. 8–12 mL/kg IBW
• D. 12–16 mL/kg IBW

Answer: (B)

Protective ventilation in ARDS aims to minimize lung injury from the ventilator by limiting how much the lungs are stretched with each breath. To do this safely, tidal volume is kept low and tied to the patient’s ideal body weight rather than actual weight, since lung size more closely matches IBW. The typical range is 4 to 8 mL per kilogram of ideal body weight, with many clinicians aiming around 6 mL/kg IBW. This small volume helps keep plateau pressures lower and reduces overdistension of the injured lungs, which lowers the risk of ventilator-induced lung injury while still allowing adequate gas exchange. Using larger tidal volumes increases the risk of volutrauma and worsens outcomes, whereas extremely low volumes can lead to insufficient ventilation and CO2 buildup, necessitating careful management.