In High Frequency Positive Pressure Ventilation, adequate CO2 elimination is typically achieved by which approach?

• A. High tidal volume with low rate
• B. Small tidal volume with high rate
• C. Low rate with high PEEP
• D. No PEEP

Answer: (B)

In high-frequency positive pressure ventilation, CO2 elimination is driven mainly by delivering a very high rate of breaths with small tidal volumes. The rapid rate pushes more breaths per minute through the lungs, increasing minute ventilation, while keeping the tidal volumes small helps prevent overdistension and high peak pressures.

Therefore, the combination of a small tidal volume with a high rate best achieves adequate CO2 elimination without causing volutrauma. Larger tidal volumes with a slower rate would raise the risk of lung injury and are less effective for CO2 removal in this mode. PEEP primarily influences oxygenation and lung recruitment, not CO2 clearance, so relying on high PEEP with a low rate does not optimize CO2 elimination. No PEEP would further compromise oxygenation and doesn’t enhance CO2 removal in this context.