Fever is common in the postoperative period, and its causes are diverse (Table 23.1). Fever may result from a benign process such as the release of pyrogens from traumatized tissue and have no bearing on the clinical outcome. Alternatively, fever may be an early sign of a potentially life-threatening infection. The clinician's challenge is to distinguish those fevers from the large pool of “routine” fevers, while avoiding the excessive use of diagnostic resources and therapeutic interventions such as antibiotics.

Evaluation of a febrile surgical patient begins with a careful history and review of the medical record. The presence of symptoms or signs of infection before the operative procedure or underlying medical problems that increase the likelihood of postoperative complications are valuable clues. The type of surgical procedure performed, operative findings, and the temporal relationship between the operation and the onset of fever are also important. Although prolonged endotracheal intubation, indwelling bladder catheters, and intravascular catheters may be important components of patient care, they violate normal host defenses and increase the likelihood of postoperative infection. When a patient has a significant infection, symptoms and signs in addition to fever usually are present. Thus, a careful physical examination is essential. Laboratory and radiographic studies should be directed by the relevant clinical data and not obtained by an undirected “shotgun” approach.

The incidence of postoperative fever varies widely depending on the surgical procedure performed and the definition of fever. There is no consensus regarding what constitutes fever in the postoperative setting.