Certified Flight Registered Nurse (CFRN) Practice Exam

Which gas law explains the pressure change observed at varying altitudes during flight?

1. Dalton's Law

2. Boyle's Law

3. Charles's Law

4. Graham's Law

The correct answer is: Boyle's Law

Boyle's Law is a fundamental principle that describes the relationship between the pressure and volume of a gas. It states that for a given amount of gas at constant temperature, the pressure of the gas is inversely proportional to its volume. This means that as one increases, the other decreases. In the context of flying at varying altitudes, as an aircraft ascends, the atmospheric pressure decreases significantly because there is less air above the airplane exerting pressure. According to Boyle's Law, if the volume of a container of gas remains constant and the external pressure decreases, the gas inside will expand, leading to a decrease in its pressure as well. This principle directly relates to the changes in cabin pressure and the ways gases behave in the human body during flight, such as the expansion of gas in body cavities, which can have physiological implications for pilots and passengers. Understanding Boyle’s Law is crucial for flight nurses, as they must be equipped to address potential altitude-related complications, like barotrauma or decompression issues, that can arise from pressure changes during flight.