For safe manual ventilation in adults, peak inspiratory pressure should generally be kept below which threshold to minimize the risk of barotrauma?

• A. Under 10 cm H2O
• B. Under 20 cm H2O
• C. Under 40 cm H2O
• D. Above 60 cm H2O

Answer: (C)

During manual ventilation, the goal is to deliver enough air to ventilate without forcing the lungs to overinflate. When pressures get too high, alveoli can stretch and rupture, leading to barotrauma such as pneumothorax or other lung injuries. That’s why keeping the peak inspiratory pressure within a safe range is essential for adult patients.

A practical target is to stay generally below 40 cm H2O. This threshold provides a balance: it allows adequate ventilation for most adults with typical chest wall mechanics and airway resistance, but it minimizes the risk of lung injury from excessive pressure. If the bag squeeze is producing pressures near or above this level, reduce the delivered tidal volume or the force of ventilation, check for airway issues or a poor mask seal, and ensure the patient isn’t obstructed or obstructing the airway.

Higher pressures, like those well above 40 cm H2O, markedly increase the chance of barotrauma, while much lower pressures (for example around 10–20 cm H2O) may fail to ventilate adequately in many adults. So the general guideline is to keep peak inspiratory pressure under 40 cm H2O to protect the lungs while providing effective ventilation.