If mechanical ventilation is indicated after lung surgery, what adjustment is recommended?

• A. Increase tidal volume
• B. Reduce tidal volume
• C. Decrease respiratory rate
• D. Increase respiratory rate

Answer: (B)

When the lungs have just undergone surgery, protecting the remaining healthy tissue from injury is the priority. A key way to do this is to use lung-protective ventilation, which means keeping the tidal volume small to limit alveolar stretch and reduce the risk of volutrauma and barotrauma. The recommended adjustment is to reduce the tidal volume to about 4–6 mL per kilogram of predicted body weight. This helps prevent overdistension of the operated lung and keeps airway pressures lower, which is especially important when the lung’s capacity and compliance are altered after surgery.

Maintaining adequate gas exchange with smaller tidal volumes is typically achieved by supporting ventilation with a carefully chosen PEEP and, if needed, adjusting the respiratory rate to maintain appropriate minute ventilation. Increasing tidal volume would increase alveolar stretch and injury risk, while simply increasing the rate without reducing tidal volume doesn’t address the injury risk and can raise pressures or CO2 changes.