What is the preferred I:E ratio in the context described?

• A. 1:2
• B. 1:1
• C. 2:1
• D. 3:1

Answer: (A)

Understanding the inspiratory to expiratory (I:E) ratio helps control how long air stays in the lungs during each breath. A 1:2 ratio means the expiratory phase is twice as long as the inspiratory phase. This longer exhale mirrors natural breathing, gives the lungs time to empty, and keeps airway pressures from rising too high. It also helps prevent air trapping and supports effective CO2 removal in many ventilation setups. If the ratio were 1:1, expiration wouldn’t be long enough, increasing the risk of air trapping and higher intrathoracic pressure. A 2:1 or 3:1 ratio would prolong inhalation, raising peak pressures and potentially causing lung injury or reduced venous return. So, 1:2 is the safer, more balanced default in standard ventilation.