What are the next steps for a patient who feels warm and may have a fever?

Immediate Assessment: Measure Core Body Temperature

The first and most critical step when a patient feels warm is to obtain an accurate core body temperature measurement to determine whether the patient has fever (≥38.3°C), is normothermic, or potentially hypothermic, as clinical impression alone is unreliable and treatment depends entirely on the actual temperature. 1, 2, 3

Why Temperature Measurement is Essential

• Clinical presentation can be misleading: A patient may feel warm to touch but have severe hypothermia, or conversely, may not feel warm despite significant fever 2, 3
• Core temperature dictates management: Treatment algorithms differ dramatically between hypothermia, normothermia, and fever states 4, 5, 1
• Peripheral assessment is inadequate: Oral temperatures have poor sensitivity for detecting true fever; tympanic and axillary methods are even less reliable 1, 3

Preferred Temperature Measurement Methods

Use core temperature monitoring when available:

• Pulmonary artery catheter temperature 1
• Bladder catheter temperature 1, 2
• Esophageal thermistor 1

If core monitoring unavailable, use:

• Rectal temperature (preferred over oral) 1, 3
• Oral temperature (acceptable but less sensitive) 1, 3

Avoid these unreliable methods for clinical decision-making:

• Tympanic (ear) thermometry 1, 3
• Temporal artery scanning 1
• Axillary measurement 1, 3

Management Based on Temperature Result

If Temperature ≥38.3°C (Fever Present)

Do NOT routinely treat fever with antipyretics solely to lower temperature, as this has not been shown to improve mortality outcomes. 1, 6

• Fever is an evolved defense mechanism that augments immune cell performance and induces stress on pathogens 6, 7
• Antipyretics (acetaminophen) should only be used if the patient desires symptomatic relief 1, 8
• Focus on identifying and treating the underlying cause rather than the temperature number itself 1, 3

Initiate diagnostic workup:

• Obtain chest radiograph for all ICU patients with new fever 1
• Draw blood cultures before starting antibiotics if patient is seriously ill or deteriorating 1
• Consider CT imaging for post-surgical patients if etiology unclear 1
• Perform bedside abdominal ultrasound for patients with recent abdominal surgery 1

Seek medical attention if: 8

• Fever worsens or lasts more than 3 days
• New symptoms develop
• Patient condition deteriorates

If Temperature 35-37°C (Normal Range)

• Patient's subjective warmth may be due to environmental factors, anxiety, or normal physiologic variation 3
• No specific temperature-directed intervention needed
• Monitor for development of true fever or other symptoms

If Temperature <35°C (Hypothermia Present)

Immediately initiate rewarming based on severity: 4, 5

Mild hypothermia (32-35°C):

• Remove wet clothing immediately 4, 5
• Move to warm environment 4, 5
• Cover with dry blankets 4, 5
• Provide warm beverages if alert 4
• Monitor temperature every 15 minutes 4

Moderate hypothermia (28-32°C):

• Continue all mild hypothermia measures 4
• Apply forced-air warming blankets (Bair Hugger) 4, 5
• Administer warmed intravenous fluids 4, 5
• Provide humidified, warmed oxygen 4, 5
• Monitor temperature every 5 minutes 4, 5

Severe hypothermia (<28°C):

• Continue all moderate hypothermia measures 5
• Activate emergency response system 4
• Handle patient gently to avoid triggering arrhythmias 4, 5
• Consider active core rewarming methods 4
• Target minimum temperature of 36°C 4, 5
• Stop rewarming at 37°C, as higher temperatures are associated with poor outcomes 4, 5

Critical Pitfalls to Avoid

• Never treat based on subjective warmth alone without measuring temperature 2, 3
• Never use unreliable temperature measurement methods for clinical decisions 1, 3
• Never routinely give antipyretics just to lower fever numbers 1, 6
• Never delay identifying and treating the underlying cause of fever 1, 3
• Never rewarm hypothermic patients above 37°C 4, 5