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Temperature measurement sites

Created: 22/1/2005

Core temperature is considered to be the temperature of blood perfusing the vital organs such as the heart and brain. Small temperature gradients exist between different parts of the body. For example 95% of all young adults would be expected to have a morning oral temperature of 36.3-37.1°C, whereas the temperature of the scrotum is carefully regulated at 32°C. Therefore the ability of measured value to reflect core temperature depends on the site chosen.

The following sites may be used:

  • Adult skin temperature sensor
  • Temporal artery thermometry
  • Tympanic membrane
  • Nasopharynx
  • Oesophagus
  • Blood
  • Bladder
  • Rectum

Adult skin temperature sensor

The Adult Skin Temperature Sensor can be used in all clinical settings requiring routine monitoring surface temperature.

  • Hypoallergenic adhesive is less traumatic to patients skin
  • Packaged sterile for convenient use in any clinical setting
  • Positive locking hub for secure cable connections
  • Highly accurate skin sensor provides reliable surface temperature readings
  • Fully compatible with most monitoring equipment

Skin sensor probe

Temporal artery thermometry

The Exergen Temporal Scanner provides a totally non-invasive, quick, easy and reproducible method of core temperature measurement. By gently stroking the Temporal Scanner across the forehead, it will provide a reading in approximately 3 seconds without the discomfort associated with oral, rectal, or tympanic thermometers.

Temporal scanner

Tympanic membrane

Tympanic membrane temperature accurately mirrors oesophageal temperature and is a good indicator of core and brain temperature. Infrared tympanic thermometers (ITT's) measure the frequency of infrared light emitted by the tympanic membrane. The operator needs to ensure that the external auditory canal is free from wax prior to use and the instrument used cautiously as perforation of the tympanic membrane has been described.

Tympanic temperature probe

The Tympanic Temperature Probe is designed for atraumatic measurement of patient temperature from the aural canal.

  • Contoured ear piece ensures simple, secure placement
  • Soft cotton tip to minimise trauma
  • Sturdy wire connector assemblies are engineered for dependability
  • Extra long lead eliminates wire tension


The temperature probe gives a fairly accurate measurement of core temperature and should be positioned just behind the soft palate. Incorrect placement leads to inaccurate results due to the cooling effects of inspired gasses. It is a less accurate measure of core temperature when compared with the oesophageal probe.


The probe is most accurate in the lower 25% of the oesophagus. When correctly placed it provides a good estimate of cardiac temperature. These probes lose their accuracy during thoracotomy, due to local cooling effects of tissues.

Oesophageal stethoscope with temperature monitor

The Oesophageal Stethoscope with temperature sensor is designed for use in surgical settings to monitor heart and respiratory sounds and to measure core body temperature of anaesthetised patients.

  • Provides outstanding heart and respiratory sound transmission
  • Available with and without temperature monitoring capability
  • Fully compatible with most monitors
  • Available in both regular and soft flexibility for enhanced patient comfort
  • Atraumatic, low friction surface for ease of insertion
  • Complete line includes all popular French sizes


Blood temperature can be measured using a thermistor attached to a pulmonary flotation catheter (Schwan-Ganz catheter). Measuring blood temperature in the pulmonary circulation is the best estimate of core temperature but this is a very invasive technique. It can also be used to measure cardiac output using thermodilution.

Click here for information regarding Pulmonary artery catheters.


Bladder temperature is determined primarily by urine flow and high flow rates are necessary for the bladder temperature to reflect core temperature. Low urinary flow makes bladder temperature difficult to interpret in relation to true core temperature.

Foley catheter temperature sensor

The Foley Catheter with temperature sensor is used for urinary drainage and simultaneous monitoring of bladder temperature.

  • Dual-purpose design can be used before, during and after surgery
  • Colour coded hubs for precise size identification
  • Positive locking connector for secure cable attachment
  • Fully compatible with most monitors
  • Safe, non-toxic components
  • Complete range of sizes: 8-18 French
  • Dependable silicone construction


Rectal temperature is influenced by the cooling effect of blood returning from the lower limbs and the heat generated by the thermogenic gut flora. The insulating effect of faeces results in rectal temperature being 0.5-1.0°C higher than core temperature and compared with other sites, response time is slow.

General purpose temperature probe

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