For a patient who develops pyrexia after surgery, which sign should the nurse monitor?

In monitoring a patient who develops pyrexia (fever) after surgery, observing an increased pulse rate is significant because fever typically induces a physiological response that includes tachycardia or an increased heart rate. This response occurs as the body attempts to regulate temperature and could indicate the body's heightened metabolic state in reaction to an inflammatory process or infection.

The increase in pulse rate can provide vital information about the patient’s hemodynamic status and may indicate that the body is mobilizing its defenses against infection. Furthermore, an increased pulse rate in the context of post-operative pyrexia can be a precursor to more serious complications, such as septicemia, particularly if accompanied by other critical signs.

While changes in appetite, the presence of a rash, and bradycardia can also be relevant in different contexts, they do not directly correlate with the immediate implications of having a fever post-surgery as effectively as an increased pulse rate does. Monitoring heart rate allows for timely interventions and management of potential complications related to infections or inflammation.