Which statement about positive-pressure ventilation is correct?

Which statement about positive-pressure ventilation is correct?

• A. With positive-pressure ventilation, more volume is required to have the same effects as normal breathing.
• B. Unlike negative-pressure ventilation, positive-pressure ventilation does not affect the esophageal opening pressure.
• C. To prevent hypotension, the EMT should increase the rate and force of positive-pressure ventilation.
• D. Positive-pressure ventilation allows blood to naturally be pulled back to the heart from the body.

Answer: (C)

Positive-pressure ventilation raises intrathoracic pressure during inspiration, which reduces venous return to the heart (preload) and can drop blood pressure. To avoid this hypotension, ventilate with the smallest effective pressures and tidal volumes that still provide adequate gas exchange, and don’t push for high rate or forceful breaths that further increase intrathoracic pressure. Increasing rate and force would actually worsen hypotension rather than prevent it. PPV also changes chest pressures and can affect areas like the esophagus, so it’s not accurate to claim there’s no effect on those pressures. And it does not pull blood back to the heart from the body; it tends to impede venous return. The key idea is understanding how intrathoracic pressure changes with PPV impact hemodynamics and adjusting ventilation to minimize those effects.

Positive-pressure ventilation raises intrathoracic pressure during inspiration, which reduces venous return to the heart (preload) and can drop blood pressure. To avoid this hypotension, ventilate with the smallest effective pressures and tidal volumes that still provide adequate gas exchange, and don’t push for high rate or forceful breaths that further increase intrathoracic pressure. Increasing rate and force would actually worsen hypotension rather than prevent it. PPV also changes chest pressures and can affect areas like the esophagus, so it’s not accurate to claim there’s no effect on those pressures. And it does not pull blood back to the heart from the body; it tends to impede venous return. The key idea is understanding how intrathoracic pressure changes with PPV impact hemodynamics and adjusting ventilation to minimize those effects.