What tidal volume (VT) should be aimed for if assist-control volume ventilation is used?

In assist-control volume ventilation, the goal is to provide adequate ventilation while minimizing the risks associated with barotrauma and volutrauma. The recommended tidal volume for patients undergoing mechanical ventilation typically falls within the range of 6-8 mL/kg of predicted body weight. This range is supported by evidence suggesting that it helps maintain sufficient minute ventilation and gas exchange without over-distending the alveoli, which can lead to lung injury.

Ventilating with a tidal volume below this range, such as 4-6 mL/kg, may result in inadequate ventilation or hypoventilation in patients with higher respiratory demands. Conversely, targeting a tidal volume greater than 8 mL/kg, such as 8-10 mL/kg or 10-12 mL/kg, can increase the risk of complications, including ventilator-associated lung injury or exacerbation of pre-existing lung conditions, particularly in patients with acute respiratory distress syndrome (ARDS). The 6-8 mL/kg guideline strikes a balance between achieving effective ventilation and minimizing potential harms.