Certified Flight Registered Nurse (CFRN) Practice Exam

Which medication makes an aircrew member more susceptible to high G forces?

1. Atenolol

2. Adrenaline

3. Amiodarone

4. Atropine

The correct answer is: Atenolol

Atenolol, a beta-blocker, is known to reduce heart rate and decrease cardiac output. In the context of increased G forces encountered in flight, this can have a significant impact on the body's ability to respond to such stressors. G forces can lead to pooling of blood in the lower extremities, which, combined with reduced heart rate and output from medications like atenolol, may compromise perfusion to vital organs and lead to symptoms such as dizziness or loss of consciousness. When aircrew members experience increased G forces, their bodies need to adequately maintain blood flow and oxygen delivery to the brain. The action of atenolol can hinder the body's normal physiological response to G forces, thus increasing the risk of G-induced loss of consciousness (GLOC) or other adverse effects related to the stresses of flight. This makes the use of atenolol particularly concerning for individuals exposed to high G conditions. Other options listed, such as adrenaline, amiodarone, and atropine, either enhance cardiovascular response or are less likely to compound the risks associated with high G forces. Adrenaline, for example, increases heart rate and contractility, which prepares the body to better handle the stresses of increased G forces, while the roles of