Which of the following actions can contribute to hypercapnia based on the material?

• A. Skip breathing
• B. Breathing normally with adequate ventilation
• C. Regular, paced breathing
• D. Effective scrubbing of CO2 in the loop

Answer: (A)

Hypercapnia occurs when the body can’t remove CO2 fast enough, so CO2 builds up in the blood. In diving, when you skip breaths, you dramatically reduce ventilation, meaning less CO2 is expelled with each breath and CO2 accumulates. This elevation in CO2 is what defines hypercapnia and it can quickly become dangerous underwater. Breathing normally with adequate ventilation keeps CO2 at safe levels, as does regular paced breathing that maintains steady ventilation. If the CO2 scrubber in a closed-loop system is working effectively, CO2 is removed from the loop, also preventing buildup. So the action that can contribute to hypercapnia is skipping breaths.