Is fever common after anesthesia in pediatric patients?

Postoperative Fever in Pediatric Patients After Anesthesia

Yes, fever is common after anesthesia in pediatric patients, occurring in approximately 30-61% of children postoperatively, but it is rarely due to infection in the early postoperative period and typically does not require extensive workup. 1, 2

Incidence and Timing

• Postoperative fever develops in 30.6% to 61.1% of pediatric surgical patients, with the higher rates observed in children with neuromuscular disorders and those undergoing complex procedures 1, 2
• Fever during anesthesia itself is actually rare, as general anesthesia inhibits fever by decreasing thermoregulatory-response thresholds to cold 3
• Multiple temperature spikes occur in approximately 56% of febrile patients, while single spikes occur in 44% 2
• The mean temperature in febrile postoperative pediatric patients is typically 38.6°C 2

Etiology and Infectious Yield

• Early postoperative fever (within 2 days) is rarely infectious in origin - only 10.7% of diagnostic tests ordered for postoperative fever were positive in one large study 2
• When infections do occur, urinary tract infections are the most common source, particularly in patients who had urinary catheters during surgery (92% of positive urine cultures occurred in catheterized patients) 2, 1
• Blood cultures are extremely low yield - only 0.69% positive rate, and all positive cultures occurred in patients with central venous catheters 1
• Chest radiographs showed infectious findings in only 3.0% of patients tested 1
• In pediatric cardiac surgery patients specifically, major infections occurred in 13.5% with fever, including pneumonia (most common) and bloodstream infections 4

Clinical Context: Distinguishing Postoperative Fever from Preoperative URI

• Preoperative upper respiratory infections (URIs) are very common pediatric pathologies and significantly increase perioperative respiratory complications (bronchospasm, laryngospasm), but the fever associated with URI is distinct from postoperative fever 5
• URI-related fever typically presents with at least two of: moderate fever, sore throat, runny nose, sneezing, dry cough, and laryngitis 5
• Postoperative fever is a normal thermoregulatory response usually of non-infectious etiology and represents inflammatory activation rather than infection 3

Recommendations for Workup

Selective rather than routine workup is appropriate for early postoperative fever in pediatric patients. 1

• Diagnostic tests performed on postoperative days 1-3 have significantly lower yield compared to tests performed after day 3 (P=0.04) 2
• Blood cultures should not be routinely obtained unless the patient has a central venous catheter and clinical signs suggesting bacteremia 2, 1
• Urinalysis and urine culture should be considered if the patient had a urinary catheter during surgery or has urinary symptoms 2, 1
• Chest radiography should be reserved for patients with respiratory symptoms or clinical findings suggesting pneumonia 2, 1

Risk Factors for True Infection

Higher-risk patients who may warrant more aggressive evaluation include: 4

• Infants (particularly those under 3 months)
• Prolonged ventilator support >2 days
• Hospital length of stay >14 days
• ICU length of stay >3 days
• Re-operation procedures
• Extubation failure

Important Caveats

• Extensive diagnostic workup is associated with prolonged hospital length of stay (P=0.02) without clear clinical benefit in most cases 2
• The cost per health effect of routine fever workup was calculated at $6,582, suggesting poor cost-effectiveness 2
• Fever may be important in host defense mechanisms and should not be routinely treated unless the risks of fever exceed the benefits 3
• Clinical assessment should guide the decision to pursue workup, with particular attention to patients with central lines, urinary catheters, or signs of clinical deterioration 2, 1