American Association of Critical-Care Nurses (AACN) Certification Practice Test

What are the two most common causes of post-operative fever?

1. Atelectasis and infection

2. Dehydration and atelectasis

3. Volumetric overload and fever

4. Pneumonia and dehydration

The correct answer is: Dehydration and atelectasis

The most common causes of post-operative fever are typically related to the body's physiological response to surgery. Among these, atelectasis, which is the collapse of part or all of a lung, is a leading factor. It can occur due to the effects of anesthesia, pain, and immobility after surgery, leading to inadequate lung expansion and inadequate ventilation. Infection is another significant cause of post-operative fever, often manifesting as surgical site infections or other types of infections acquired during the hospital stay. These infections can develop 2-5 days post-surgery depending on the type and complexity of the procedure performed. While dehydration can contribute to various complications after surgery, it is not considered one of the primary causes of post-operative fever in the general context. Similarly, volumetric overload typically refers to fluid volume excess and is more associated with cardiac issues or overload related to IV fluid management rather than being a direct cause of fever. Pneumonia can lead to fever but is more specific than the broader term of atelectasis, which can lead to hypoventilation and fever through inflammatory responses. Thus, the correct answer identifies the most common reasoning behind post-operative fever, highlighting atelectasis and infection as key contributors in the post-surgical context.