Body Temperature

Aka: Body Temperature, Temperature, Rectal Temperature, Oral Temperature, Tympanic Temperature, Axillary Temperature

1. See Also
   1. Fever
   2. Heat Illness
   3. Hypothermia
   4. Vital Signs
   5. Pediatric Vital Signs
2. Technique: Rectal Temperature
   1. Procedure
      1. Apply vaseline or KY Jelly to rectal thermometer
      2. Patient lies on their side with top leg flexed forward
      3. Children and uncooperative patients should be held by an assistant to prevent movement
      4. One hand spreads the buttocks and exposes the anal region
      5. Thermometer tip gently inserted through anus into Rectum 0.5 to 1 inch depth
      6. Stop insertion if any resistance is met
         1. May use the reading if the depth is at least 0.5 inches
      7. Thermometers typically indicate with sound when the reading has stabilized and Temperature may be read
   2. Advantages
      1. Most accurate, non-invasive method for detecting fever
   3. Disadvantages
      1. Lag core Temperature changes
      2. Variable readings depending on depth or insertion and presence of stool in Rectum
      3. Risk of contagious illness spread
      4. Discomfort for both the patient and the parent performing the Temperature
      5. Case reports of rectal perforation in infants
3. Technique: Oral Temperature
   1. Procedure
      1. Patient sits in comfortable, stable position
      2. Thermometer placed under Tongue and with lips closed around it
      3. Patient instructed not to bite down on thermometer
      4. Thermometers typically indicate with sound or other signal when the reading has stabilized and Temperature may be read
   2. Advantages
      1. Comfortable, easily accessible site for Temperature measurement (reflects the lingual artery Temperature)
      2. More accurate than acillary Temperatures (but less accurate than Rectal Temperatures)
   3. Disadvantages
      1. Altered by eating or drinking with the prior 15 minutes
      2. Adequate reading requires a closed mouth and thermometer held under the Tongue for 3-4 minutes
      3. Not appropriate for uncooperative or unconscious patients
      4. Not appropriate for young children especially under age 2 years
         1. Not able to maintain sublingual positioning, may bite thermometer
         2. Pacifier thermometers are an alternative option in this age, but must stay in mouth for 6 minutes
4. Technique: Tympanic Temperature
   1. Procedure
      1. Insert thermometer tip into ear canal
      2. Press start
      3. Wait for sound or other signal to indicate Temperature may be read
   2. Advantages
      1. Fast, convenient, comfortable and easy to perform
   3. Disadvantages
      1. Poor accuracy (similar to Axillary Temperature)
      2. Affected by environmental Temperature, Cerumen Impaction and Otitis Media
      3. Not appropriate for under age 6 months
5. Technique: Forehead or temoral Temperature
   1. Procedure
      1. Infrared device placed over temporal artery distribution region
   2. Advantages
      1. Fast and simple
   3. Disadvantages
      1. Most expensive of thermometers
      2. Error prone
6. Technique: Axillary Temperature
   1. Procedure
      1. Place thermometer snugly against skin in axilla with arm adducted
      2. Thermometers typically indicate with sound or other signal when the reading has stabilized and Temperature may be read
   2. Advantages
      1. Least invasive method
      2. Recommended by AAP for infants (due to home risk of rectal perforation with Rectal Temperature)
   3. Disadvantages
      1. Adequate reading requires thermometer kept within the axilla for 4 minutes
      2. Least accurate method for detecting fever
         1. Not recommended for medical facilities to detect fever and on which to base clinical decision making
         2. One study found Axillary Temperatures were accurate in under 3 months of age
            1. Shann (1996) Arch Pediatr Adolesc Med 150:74-8 [PubMed]
   4. Interpretation
      1. Age <5 weeks old
         1. Rectal = Axillary Temperature + 0.2/week of age (C)
      2. Age >1 month old
         1. Rectal = Axillary Temperature + 1 (Celsius)
7. Technique: Core Temperature
   1. Devices
      1. Esophageal thermometer
      2. Bladder thermometer
   2. Advantages
      1. Most accurate methods of Temperature monitoring
   3. Disadvantages
      1. Invasive and used only in specific, intensive indications
8. Precautions
   1. Avoid wearable thermometers and color change strips due to unreliability
9. References
   1. (2016) Presc Lett 23(11)
   2. (2000) Paediatr Child Health 5(5): 273-6 [PubMed]