What are the guidelines for treating fever?

Guidelines for Treating Fever

Fever management should focus on patient comfort rather than temperature reduction alone, as routine use of antipyretics solely for temperature reduction is not recommended in critically ill patients. 1, 2

Definition and Measurement of Fever

• Fever is defined as a single temperature measurement ≥38.3°C according to the Society of Critical Care Medicine and Infectious Diseases Society of America 1
• Central temperature monitoring methods (pulmonary artery catheters, bladder catheters, or esophageal thermistors) are preferred when these devices are in place 1, 3
• When central monitoring is unavailable, oral or rectal temperatures are preferred over less reliable methods like axillary or tympanic measurements 1

General Approach to Fever Management

• Antipyretic medications should not be routinely used for the specific purpose of reducing temperature alone, as this has not been shown to improve mortality outcomes 1, 2
• For patients who desire symptomatic relief, antipyretic medications are recommended over non-pharmacologic cooling methods 1, 2
• Acetaminophen (paracetamol) is the preferred first-line antipyretic, particularly in children 2, 4
• Physical cooling methods such as fanning, cold bathing, and tepid sponging cause discomfort and are not recommended, especially for children 2, 5

Diagnostic Workup for Fever

• A chest radiograph is recommended for all patients with new fever in the ICU setting 1, 6
• Blood cultures should be obtained before initiating antimicrobial therapy, especially if the patient is seriously ill or deteriorating 6
• For patients with recent thoracic, abdominal, or pelvic surgery, CT imaging should be considered if an etiology is not readily identified by initial workup 1
• In patients with fever and recent abdominal surgery or abdominal symptoms, a formal bedside diagnostic ultrasound of the abdomen is recommended 1

Special Populations

Critically Ill Patients

• Fever management in critically ill patients should be individualized based on physiologic reserves 2
• Meta-analysis of 13 RCTs showed fever management reduced body temperature but did not improve 28-day mortality or hospital mortality 2

Patients with Neutropenia

• For patients with neutropenia and fever, hospitalization and empiric antibacterial therapy with vancomycin plus antipseudomonal antibiotics is recommended 1, 6
• In high-risk neutropenic patients with fever, use monotherapy with antipseudomonal β-lactam or carbapenem as empiric therapy 1
• Consider discontinuation of empiric antibiotics at 72 hours in low-risk neutropenic patients who have negative blood cultures and have been afebrile for at least 24 hours 1

Children

• In children, fever management should focus on improving overall comfort rather than normalizing body temperature 4, 5
• Current evidence suggests no substantial difference in safety and effectiveness between acetaminophen and ibuprofen in generally healthy children with fever 4
• Antipyretic use is not effective in preventing febrile convulsions or adverse effects of vaccines in children 5

Pharmacological Management

• Acetaminophen (paracetamol) is generally the first-line agent for fever management 2, 5
• Ibuprofen is an effective alternative, but should be used with caution in patients with certain conditions 7, 5
• Avoid ibuprofen in children with chickenpox or dehydration 5
• Caution with NSAIDs in patients with:
  • Aspirin sensitivity or asthma (risk of cross-reactivity) 7
  • Renal impairment (may reduce natriuretic effect of diuretics) 7
  • Cardiovascular disease (increased risk of thrombotic events) 7

Common Pitfalls to Avoid

• Treating the number on the thermometer rather than the patient's symptoms and comfort 2
• Using unreliable temperature measurement methods (tympanic, temporal) in critical decision-making 2
• Failing to identify and treat the underlying cause of fever 2, 6
• Combined or alternating use of antipyretics is discouraged due to potential complications and risk of unsafe use 4, 5
• Delaying effective antimicrobial therapy when infection is suspected, which has been associated with increased mortality 6

Emerging Evidence

• A 2023 study found that the combination of paracetamol/ibuprofen (500/150 mg) was more effective than paracetamol alone (1000 mg) in patients with bacterial fever one hour after administration, though efficacy was similar after two hours 8
• This suggests that combination therapy might provide faster relief in certain cases, though the general recommendation remains to use single agents when possible 8, 4