From the Guidelines
Post-operative fever should be evaluated using a combination of physical examination, laboratory tests, and imaging studies, with a focus on identifying the underlying cause and initiating targeted treatment as soon as possible, as recommended by the most recent guidelines from the Society of Critical Care Medicine and the Infectious Diseases Society of America 1.
Initial Assessment
The initial assessment of post-operative fever should include a thorough history, physical examination, and review of vital signs. Basic diagnostic tests such as complete blood count, urinalysis, chest X-ray, and wound examination should be performed to identify potential causes of fever.
Diagnostic Approach
The diagnostic approach to post-operative fever can be guided by the "5 Ws" framework: Wind (pulmonary causes), Water (urinary tract infections), Wound (surgical site infections), Walking (deep vein thrombosis), and Wonder drugs (medication reactions). For early fevers (within 48 hours), atelectasis is a common cause, requiring incentive spirometry and early mobilization 1.
Imaging Studies
Imaging studies such as chest radiograph and CT scans may be necessary to evaluate the underlying cause of fever, especially in patients who have recently undergone thoracic, abdominal, or pelvic surgery 1.
Laboratory Tests
Laboratory tests such as blood cultures, urinalysis, and wound cultures may be necessary to identify the underlying cause of fever and guide antibiotic therapy.
Treatment
Treatment of post-operative fever should be targeted at the underlying cause, with antibiotics being used judiciously to minimize the risk of antibiotic resistance and other complications.
- Key considerations in the treatment of post-operative fever include:
- Early recognition and treatment of the underlying cause
- Use of antibiotics only when necessary and for the shortest duration possible
- Monitoring for potential complications such as sepsis and organ dysfunction
- Consideration of alternative causes of fever, such as medication reactions or deep vein thrombosis.
From the Research
Diagnosis of Post-Op Fever
The diagnosis of post-operative fever involves a systematic approach to determine the underlying cause. According to 2, early post-operative fever is a common event and rarely caused by an infection. The study found that a brief bedside evaluation has the highest yield for determining the fever etiology, and extensive evaluations with cultures and chest imaging have little to no benefit in patients admitted for elective surgery.
Key Considerations
When evaluating post-operative fever, the following key considerations should be taken into account:
- The timing of the fever: fever that develops after the first 2 days following surgery is more likely to have an infectious cause 3
- The patient's medical history and physical examination findings 4
- The type of surgery performed 4
- The possibility of noninfectious causes, such as drug fever, blood product reaction, or infections related to intravenous lines 3
Diagnostic Approach
A focused approach to evaluating post-operative fever is recommended, rather than a "shotgun" approach 3. The "four Ws" mnemonic can be helpful in guiding the evaluation: wind (pulmonary causes), water (urinary tract infection), wound (surgical site infection), and "what did we do?" (iatrogenic causes) 3. A systematic approach to febrile post-operative patients can help clinicians make better use of resources, limit costly workups, and improve patient outcomes 5.
Common Causes
Common causes of post-operative fever include: