Emergency Medical Technician (EMT) Intermediate Practice Exam

When ventilation is compromised but perfusion continues, what occurs?

1. Hypoxemia is present

2. Gas exchange does not take place

3. The patient experiences hyperoxia

4. Carbon dioxide levels rise dramatically

The correct answer is: Gas exchange does not take place

When ventilation is compromised while perfusion continues, gas exchange does not take place effectively. This situation arises because ventilation refers to the movement of air in and out of the lungs, while perfusion involves the blood flow to the pulmonary capillaries. If there is insufficient ventilation, despite continued blood flow, the oxygen from the air cannot be properly delivered to the blood, and carbon dioxide cannot be effectively removed from the blood. The lack of adequate gas exchange leads to a number of physiological challenges. While other conditions might arise in this scenario, the primary effect is that the fundamental process of exchanging oxygen for carbon dioxide fails, which can lead to a series of complications, including hypoxemia and an accumulation of carbon dioxide in the bloodstream. Thus, the inability for gas exchange to occur is the core issue when ventilation is compromised, underscoring the interdependence of these two vital processes in maintaining adequate respiratory function.