What is the approach to fever in the adult Intensive Care Unit (ICU) patient?

From the Guidelines

The approach to fever in the adult ICU patient should prioritize identifying the source of infection while initiating appropriate management, with a focus on performing a chest radiograph for patients who develop fever during ICU stay, as recommended by the Society of Critical Care Medicine and the Infectious Diseases Society of America guidelines 1. When evaluating a new fever in an adult ICU patient, it is essential to consider both infectious and non-infectious causes, with non-infectious causes including drug reactions, thromboembolism, transfusion reactions, and post-surgical inflammation 1. The initial evaluation should include:

• Obtaining complete vital signs and performing a physical examination to identify potential infection sources
• Collecting blood cultures before starting antibiotics
• Ordering relevant laboratory tests, such as complete blood count, comprehensive metabolic panel, urinalysis, and cultures from suspected sites
• Considering imaging studies like chest X-ray, ultrasound, or CT scan based on clinical suspicion Key recommendations for fever management in the ICU include:
• Performing a chest radiograph for patients who develop fever during ICU stay 1
• Avoiding routine use of antipyretic medications for the specific purpose of reducing temperature, but considering their use for patient comfort 1
• Using antipyretics over non-pharmacologic methods to reduce body temperature when necessary 1
• Collecting at least two sets of blood cultures from different anatomical sites without a time interval between them 1 It is crucial to address the underlying cause of fever rather than just treating the temperature elevation, as fever represents an adaptive host response that may aid in fighting infection 1. Daily reassessment of antibiotic therapy is essential, with de-escalation based on culture results and clinical improvement, typically within 48-72 hours.

From the Research

Approach to Fever in Adult ICU Patients

The approach to fever in adult Intensive Care Unit (ICU) patients involves a thorough and systematic evaluation to determine the underlying cause of the fever.

• The first step is a complete assessment, including a thorough physical assessment and an evaluation of the history of present illness as well as a detailed review of all the patient's medications 2.
• Infection should always be a primary consideration for the cause of a fever, and evaluating each body system can help match symptoms with a possible cause for fever 2, 3.
• Noninfectious causes of fever also need to be included in the differential diagnostic process 2, 4.
• A cost-conscious approach to obtaining cultures and imaging studies should be undertaken if it is indicated after a clinical evaluation 5.
• The goal of this approach is to determine, in a directed manner, whether or not infection is present, so additional testing can be avoided and therapeutic options can be made 5.

Evaluation and Management

• The evaluation of the febrile patient in the ICU requires a meticulous and attentive approach, and managing ICU patients with fever should be towards a more restrictive approach than simply starting antibiotic therapy 3.
• If overt infection is not found upon initial evaluation, antibiotics should be withheld if possible, and empiric therapy may be started in unstable patients, but should be stopped within a reasonable time frame if no infection is evident 4, 6.
• Prolonged antibiotics should not be given for presumed but unproven infection 4.
• Familiarity with the techniques used for diagnosis of infections and their appropriate interpretation and limitations is essential for adequate evaluation of the febrile ICU patient 4.