From the Guidelines
Postoperative fever should be evaluated based on the timing of the fever, with early fevers (first 48 hours) typically due to non-infectious causes and fevers after 48 hours more likely to indicate infections or other complications, as suggested by 1. When evaluating postoperative fever, it is essential to consider the "5 Ws" framework: Wind (atelectasis, pneumonia), Water (urinary tract infection), Wound (surgical site infection), Walking (deep vein thrombosis, pulmonary embolism), and Wonder drugs (medication reactions).
- The timing of the fever is crucial, as early fevers (first 48 hours) are often non-infectious in origin, while fevers after 48 hours may indicate infections or thromboembolism, as noted in 2.
- Initial management includes a thorough physical examination, chest X-ray, urinalysis, wound inspection, and blood cultures if indicated.
- Treatment depends on the identified cause: atelectasis requires incentive spirometry and early mobilization; infections need appropriate antibiotics (e.g., cefazolin 1-2g IV every 8 hours for wound infections), as recommended in 3; DVT requires anticoagulation with heparin or enoxaparin; and medication reactions necessitate discontinuation of the offending agent.
- Antipyretics like acetaminophen (650mg every 6 hours) can provide symptomatic relief, as mentioned in the example answer.
- The physiological basis for postoperative fever involves inflammatory mediators released during surgical stress and the body's normal response to tissue injury, which can elevate the hypothalamic temperature set point, as discussed in 4.
- Not all postoperative fevers require antibiotics, as many are non-infectious and self-limiting, as emphasized in 5 and 1. Some key points to consider when evaluating postoperative fever include:
- The algorithm for the management and treatment of surgical site infections (SSIs) provided in 3 can guide the evaluation and treatment of postoperative fever.
- The integrity of host defenses, including age, malnutrition status, diabetes, smoking, obesity, colonization with microorganisms, length of hospital stay or previous hospitalization, shock and hypoxemia, and hypothermia, can impact the risk of SSI, as noted in 1.
- Incisional SSIs should always be drained, irrigated, and if needed, opened and debrided, as recommended in 1.
From the Research
Definition and Causes of Postop Fever
- Postoperative fever is a common condition that can occur after surgery, with various causes, including infectious and non-infectious etiologies 6.
- Not all postoperative fevers have an infectious cause, but they all require thorough investigation to rule out life-threatening conditions 7.
Risk Factors for Postop Fever
- Patient-related risk factors for post-operative sepsis, which can cause fever, include male gender, pre-existing heart failure, diabetes, and chronic kidney disease 8.
- Surgery-related risk factors for post-operative sepsis include emergency surgery, peri-operative blood transfusion, inpatient hospital stay, and open surgery 8.
Management of Postop Fever
- Early recognition and appropriate treatment of postoperative infections can relieve anxiety, reduce hospital costs, and increase patient survival rates 6.
- The management of postoperative fever requires a thorough investigation to rule out life-threatening conditions, and subsequent testing should be based on clinical findings 6.
- Biomarkers such as procalcitonin can provide decision support for antibiotic use and may identify patients with a low likelihood of infection 9.
Relationship with Sepsis
- Sepsis is a common consequence of infection, associated with a mortality rate > 25%, and can be a cause of postoperative fever 9.
- Post-operative sepsis can involve drug-resistant pathogens, and this often necessitates consideration of newer antimicrobial agents 9.
- The adjusted overall incidence of surgical sepsis was 1.84%, and recognizing risk factors could assist in the pre-operative identification of patients at risk of post-operative sepsis 8.