Neonatal Nurse Practitioner Practice Exam

Resistance in a respiratory context is defined as what?

1. Change in volume divided by change in pressure

2. Change in pressure divided by change in flow

3. Flow rate divided by tidal volume

4. Change in compliance over time

The correct answer is: Change in pressure divided by change in flow

In the context of respiratory physiology, resistance is defined as the change in pressure divided by the change in flow. This definition reflects how much pressure is needed to maintain a given airflow through the airways. Higher resistance indicates that greater pressure is required to achieve the same airflow, which is a key concept in understanding respiratory mechanics. When considering the factors that affect breathing, resistance plays a crucial role in determining how easily air can move in and out of the lungs. Various conditions such as asthma, bronchospasm, or inflammation can increase airway resistance, leading to increased work of breathing and altered gas exchange. The other definitions relate to different aspects of respiratory mechanics. The change in volume divided by change in pressure pertains to compliance, which describes how easily the lungs expand with a given pressure change. The flow rate divided by tidal volume pertains more to ventilation efficiency rather than resistance. Lastly, change in compliance over time is not a standard measure of resistance but rather relates to how the lung's ability to stretch changes with conditions such as pulmonary fibrosis or edema. Understanding resistance in this way is crucial for assessing and managing respiratory problems, particularly in neonates, who may have different baseline resistance due to their anatomical and physiological characteristics.