Certified Pulmonary Function Technologist (CPFT) Practice Exam

When creating a hyperventilation situation, which gas concentrations should you utilize?

1. 5% CO2, 21% O2, Balance Air

2. 5% CO2, 100% O2, Balance N2

3. 10% CO2, 21% O2, Balance He

4. 0% CO2, 21% O2, Balance Ar

The correct answer is: 5% CO2, 21% O2, Balance Air

In a hyperventilation scenario, the objective is to create a condition where the participant is breathing at an increased rate, which typically leads to a decrease in carbon dioxide (CO2) levels in the blood. Utilizing a gas mixture with 5% CO2 and 21% O2 is significant because the addition of CO2 serves to stimulate increased breathing while still maintaining an adequate oxygen concentration for the subject. When testing for hyperventilation, it's essential to monitor the response of the pulmonary system to hypercapnia (elevated CO2 levels) and resultant decreases in oxygen levels in a controlled manner. The balance being made up of air ensures that the participant's gas exchange physiology is being evaluated under realistic conditions without introducing an excess of other gases which could complicate or skew the observation. The other options either provide unsuitable concentrations of gases or combinations that do not effectively simulate the intended hyperventilation condition. For instance, using 100% O2 can lead to oxidative stress without the intended hyperventilation effect; high concentrations of helium may alter the density and flow characteristics of the gases; providing 0% CO2 could prevent the desired physiological response associated with hyperventilation. Thus, creating a hyperventilation situation with the appropriate mix