Which strategy recruits alveoli and maintains recruitment during ventilation?

• A. Two-level CPAP (IPAP/EPAP)
• B. High FiO2
• C. Shortened inspiratory time
• D. Increased respiratory rate

Answer: (A)

Recruting and keeping alveoli open during ventilation relies on a pressure strategy that both opens collapsed units and prevents them from collapsing at the end of a breath. Two-level CPAP uses a higher inspiratory pressure (IPAP) to actively open or recruit alveoli, then lowers the pressure at expiration to EPAP so the alveoli stay open between breaths. That combination—opening during inspiration and maintaining openness during expiration—keeps more alveoli recruited throughout ventilation and helps improve overall gas exchange and oxygenation. Simply using a higher oxygen fraction won’t mechanically prevent derecruitment; shortening the inspiratory time lowers the opportunity to open alveoli; and increasing the respiratory rate can reduce the time available for recruitment and may promote air trapping or instability.