A deflated reservoir bag could indicate which of the following?

• A. Circuit leak, detached patient from circuit, too low FGF or wrong size bag for patient
• B. Overinflation
• C. High FGF
• D. System failure

Answer: (A)

A deflated reservoir bag means gas isn’t reaching or staying in the bag, so ventilation isn’t being delivered to fill it. The most likely reasons are a leak in the breathing circuit or a detachment of the patient from the circuit, which lets fresh gas escape instead of filling the bag; too low fresh gas flow relative to the patient’s ventilatory needs; or using a bag that is too small for the patient, preventing adequate expansion. By contrast, overinflation or high fresh gas flow would tend to fill or expand the bag, and a general system failure would present with broader issues beyond just a deflated bag.