On conventional ventilation, carbon dioxide elimination is most effectively increased by raising:

• A. Tidal volume
• B. Positive end expiratory pressure
• C. Respiratory rate
• D. Minute ventilation

Answer: (D)

CO2 elimination relies on alveolar ventilation—the amount of fresh gas reaching the alveoli each minute. This is what actually carries away produced CO2. On a conventional ventilator, alveolar ventilation is described by minute ventilation, which is the product of tidal volume and respiratory rate. Therefore, increasing minute ventilation directly raises the rate at which CO2 is removed from the lungs.

Raising tidal volume alone does increase ventilation per breath, but it is limited by the risk of high airway pressures and volutrauma, and it doesn’t guarantee a greater net CO2 removal if the rate is unchanged. Increasing only the respiratory rate also boosts ventilation but can reduce expiratory time and cause air trapping if not carefully managed. PEEP helps with oxygenation and lung recruitment but does not directly boost CO2 clearance. Since CO2 elimination tracks with the overall minute ventilation, that measure is the most effective lever to increase CO2 removal on conventional ventilation.