SCCM and IDSA Guidelines for Evaluating New Fever in Adult Patients in the ICU

Central temperature monitoring methods, including thermistors for pulmonary artery catheters, bladder catheters, or esophageal balloon thermistors, are preferred when these devices are in place or accurate temperature measurements are critical to diagnosis and management. For patients without these devices in place, we suggest using oral or rectal temperatures over other temperature measurement methods that are less reliable (such as axillary or tympanic membrane temperatures, noninvasive temporal artery thermometers, or chemical dot thermometers).
Quality of evidence: Very low

For critically ill patients with fever, we suggest avoiding the routine use of antipyretic medications for the specific purpose of reducing the temperature.
Quality of evidence: Moderate

For critically ill patients with fever who value comfort by reducing temperature, we suggest using antipyretic medications over nonpharmacologic methods to reduce body temperature.
Quality of evidence: Low

For patients who develop a fever during their ICU stay, we recommend performing a chest radiograph.

For patients who have recently undergone thoracic, abdominal, or pelvic surgery, we recommend performing CT (in collaboration with the surgical service) as part of a fever workup if an etiology is not readily identified by the initial workup.

For critically ill patients with fever in whom other diagnostic tests have failed to establish an etiology, we suggest performing an 18F-fluorodeoxyglucose (18F-FDG) PET or CT if the risk of transport is deemed acceptable.
Quality of evidence: Very low

The panel found insufficient evidence to issue a recommendation regarding the use of WBC scans for patients with fever without an established etiology.

For critically ill patients with fever and no abdominal signs or symptoms or liver function abnormalities and no recent abdominal surgery, we recommend against the routine use of a formal abdominal ultrasound or POCUS as an initial investigation.

In patients with fever and recent abdominal surgery or in any patient with either abdominal symptoms or suspicion of an abdominal source (e.g., abnormal physical examination/POCUS, increased transaminases, or alkaline phosphatase, and/or bilirubin), we recommend performing a formal bedside diagnostic ultrasound of the abdomen.

For critically ill patients with fever and an abnormal chest radiograph, we suggest performing a thoracic bedside ultrasound when sufficient expertise is available to reliably identify pleural effusions and parenchymal or interstitial lung pathology.
Quality of evidence: Low

The panel found insufficient evidence to issue a recommendation regarding the use of thoracic bedside ultrasound for patients with fever without chest radiograph abnormalities.

For ICU patients with fever without an obvious source and who have a central venous catheter, we recommend simultaneous collection of central venous catheter and peripherally drawn blood cultures to allow calculation of differential time to positivity.

In patients with fever in the ICU in whom central venous catheter cultures are indicated, we recommend sampling at least two lumens.

For critically ill patients with a new fever of unclear origin, we suggest that, if rapid molecular tests on blood are performed, they should be used only with concomitant blood cultures.
Quality of evidence: Very low

When performing blood cultures in adult ICU patients, we recommend sequentially collecting at least two sets of blood cultures (ideally 60 mL of blood total), from different anatomic sites, without a time interval between them.

For febrile ICU patients with pyuria and in whom UTI is suspected, we recommend replacing the urinary catheter and obtaining urine cultures from the newly placed catheter.

For critically ill patients with new fever and suspected pneumonia, or new upper respiratory infection symptoms (e.g., cough), we suggest testing for viral pathogens using viral NAAT panels.
Quality of evidence: Very low

The panel found insufficient evidence to issue a recommendation on performing routine blood testing for viral pathogens (e.g., herpesviruses, adenovirus) in immunocompetent patients in the ICU.

For critically ill patients with a new fever, we recommend testing for SARS-CoV-2 by PCR based on levels of community transmission.

If the probability of bacterial infection is deemed low to intermediate in a critically ill patient with a new fever and no clear focus of infection, we suggest measuring PCT in addition to bedside clinical evaluation versus bedside clinical evaluation alone.
Quality of evidence: Very low

If the probability of bacterial infection is deemed high in a critically ill patient with a new fever and no clear focus of infection, we suggest not measuring PCT to rule out bacterial infection.
Quality of evidence: Very low

If the probability of bacterial infection is deemed low to intermediate in a critically ill patient with a new fever and no clear focus of infection, we suggest measuring CRP in addition to bedside clinical evaluation versus bedside clinical evaluation alone.
Quality of evidence: Very low

If the probability of bacterial infection is deemed high in a critically ill patient with a new fever and no clear focus of infection, we suggest not measuring CRP to rule out bacterial infection.
Quality of evidence: Very low

If the probability of bacterial infection is deemed low to intermediate in a critically ill patient with a new fever and no clear focus of infection, we suggest measuring either serum PCT or CRP to rule out bacterial infection.
Quality of evidence: Very low