Postoperative fever refers to an elevated body temperature (≥ 38.5 °C) occurring after a recent surgical procedure.
The most common causes of postoperative fever are often summarized for medical students by a mnemonic beginning with the letter W. The classic list consists of five W's – Wind, Water, Wound, Walking, and Wonder Drugs,[1] but two other causes should also be considered – Wing/Waterway and (W)abscess.
Other important causes of early post-operative fever that are omitted from this list include malignant hyperthermia, a potentially life-threatening but treatable response to inhalational anesthetic and paralytic agents.
Early postoperative fever (i.e., within the first 48 hours post-operatively) has often been ascribed to atelectasis, or splinting, but it is most likely part of a natural and non-infectious inflammatory response (with sympathetic nervous system involvement) to the tissue injury sustained during surgery; it generally requires no medical intervention except antipyretics and extra fluid intake.
Laboratory testing and imaging is generally deferred for evaluation of fever that occurs within the first 48 hours post-operatively, unless prompted by specific findings in the history and physical exam.