Anesthesia Technician Practice Exam

What is the result of rebreathing carbon dioxide in a circle system with a malfunctioning unidirectional valve?

1. Hypercapnia

2. Respiratory acidosis

3. Hypoxemia

4. Respiratory alkalosis

The correct answer is: Hypercapnia

Rebreathing carbon dioxide in a circle system with a malfunctioning unidirectional valve leads to hypercapnia, which is characterized by an increased level of carbon dioxide (CO2) in the bloodstream. In a properly functioning circle system, unidirectional valves ensure that exhaled gases flow in one direction, preventing the rebreathing of CO2. However, when these valves malfunction, CO2 from the exhaled air can be reintroduced into the fresh gas flow, leading to a buildup of CO2 rather than its proper expulsion. This accumulation of CO2 can overwhelm the body’s ability to eliminate it through the lungs, resulting in elevated arterial CO2 levels. The physiological reaction to hypercapnia includes an increase in respiratory drive as the body attempts to compensate for the high levels of CO2. While respiratory acidosis can occur as a consequence of hypercapnia due to the accumulation of carbon dioxide forming carbonic acid in the blood, the direct result of rebreathing CO2 itself is the rise in CO2 levels, hence the immediate and primary response is hypercapnia. Hypoxemia and respiratory alkalosis are not directly related to the rebreathing of CO2 in this context; hypoxemia refers to