Certified Transport Registered Nurse Certification Practice Exam

In capnography, what does a rise in EtCO2 typically indicate?

1. Hypoventilation

2. Hyperventilation

3. Obstructed airway

4. Decreased cardiac output

The correct answer is: Hypoventilation

In capnography, a rise in end-tidal carbon dioxide (EtCO2) levels generally indicates hypoventilation. This occurs because hypoventilation causes a decrease in the elimination of carbon dioxide from the body, leading to an accumulation of CO2 in the bloodstream and subsequently reflected in the expired air. As carbon dioxide levels increase in the blood, this results in higher EtCO2 readings during capnography. Monitoring EtCO2 is crucial in a clinical setting because it provides real-time feedback about a patient's ventilatory status. In situations of hypoventilation, such as respiratory depression or inadequate ventilation, the body retains more carbon dioxide, resulting in elevated levels. Therefore, recognizing a rise in EtCO2 is vital for the assessment and management of a patient's respiratory function. The other options either discuss conditions that would not result in a rise in EtCO2 or focus on ventilatory status that would lead to a decrease in carbon dioxide levels, such as hyperventilation which decreases EtCO2, or conditions affecting airway or cardiac output that would not consistently correlate with rising EtCO2 levels.