You are ventilating a 40-year-old uninjured man who is apneic but has a pulse. When your partner reassesses his blood pressure, she notes that it has decreased significantly from previous readings. You should:

• A. Increase the rate at which you are ventilating and reassess his blood pressure.
• B. Perform a head-to-toe assessment to look for signs of bleeding.
• C. Reduce the rate or volume of the ventilations you are delivering.
• D. Increase the volume of your ventilations and reassess his blood pressure.

Answer: (C)

The main idea is to ventilate in a way that doesn’t impede return of blood to the heart. When you’re providing breaths to an apneic patient who still has a pulse, too-rapid or too-forceful ventilation can raise intrathoracic pressure and drop venous return, which lowers cardiac output and blood pressure. A significant BP drop after starting ventilation means you’re likely over-ventilating. The correct action is to reduce either the rate or the volume of ventilations to prevent hyperinflation, then reassess blood pressure and perfusion.

Increasing the rate or the volume would probably worsen the hypotension, while a full head-to-toe assessment is important but doesn’t address the immediate hemodynamic change caused by ventilation. Aim for gentle ventilations with appropriate chest rise and recheck the BP after adjusting.