Application
Motivation
Anesthesia disables animal temperature control. This causes the animal's temperature
to fall, and an external heat source is needed to maintain body temperature. However,
there is little margin between normal animal temperatures of 37.5 or 38.5 deg C
for rats,
and stressful/lethal
high temperatures in the 40 to 45 degree range.
Body temperature monitoring and control is needed to minimize the effects
of that stress on physiological and biochemical parameters,
not to mention survivability; data from dead rats is difficult to publish.
Therefore, it is important to know the accuracy of the temperature measuring device.
Method
To be described as ANSI (American National Standards Institute) compliant there are are accuracy standards
that thermocouple wire must conform to,
Cleveland Electric Laboratories.
The tolerances per ANSI circular MC96.1-1982 are:
Type K, the larger of +-2.2 deg C or +-0.75% of reading;
Type T, the larger of +-1.0 deg C or +-0.75% of reading.
Clearly type T wire is better than type K.
Special Tolerance Per ANSI MC96.1 is
Type T, the larger of +-0.5 deg C or +-0.4% of reading.
Special tolerance is even better; this is the wire that we use in our probes.
This is the best accuracy that can be attained from the wire alone, and ignores other systemic errors that may add to it. It is barely good enough accuracy for staying out of the danger zone. It is not good enough, for example, for usage in rat colonies where baseline values need to be repeatable between two or more temperature meters; switching meters or probes could falsely signal or mask the onset of infectious disease.
It is our experience that +-0.1 deg C accuracy for the measurement is more than adequate to give confidence in comparing readings taken with different instruments or different probes.
To perform this calibration an NIST (National Institute of Standards Technology) traceable thermometer (an ASTM-91C-CC with a range of 20 to 50 deg C with 1/10 deg divisions) certified to have a -0.01 deg C correction at 37.00 deg C is used to calibrate a YSI49TA thermometer with a YSI 400 probe. This thermistor probe serves as a transfer standard in a water bath that is used to calibrate the CyQ111 with it's probe to +-0.05 degrees Celsius.
Thus, we feel confident in specifiying an accuracy of 0.1 degree Celsius.
Options and Accessories
T_36 probe: 1 mm, 0.025 inch (25 mil) , 36 gage probe epoxy tipped (tested on
100 g rat pups).
Literature References to CyQ 111
Clinical Disease Scoring Systems for Rodents. Prepared by VCS Veterinarians, 6/10/05. "Rodent thermometers are available from several vendors. See: www.cyq.com"
Buffie Clodfelder-Miller, Patrizia De Sarno, Anna A. Zmijewska, Ling Song and Richard S. Jope. Physiological and Pathological Changes in Glucose Regulate Brain Akt and Glycogen Synthase Kinase-3. J. Biol Chem. 2005, December 2; 280(48): 39723-39731. (CyQ 111)
Janssen, Ben J.A., Tijl De Celle, Jacques J.M. Debets, Agnieszka E. Brouns, Michael F. Callahan and Thomas L. Smith. Effects of anesthetics on systemic hemodynamics in mice. Am J Physiol Heart Circ Physiol In press (May 20, 2004)
Zerwas, Meike P. Generation and analysis of a mouse line with neuronal transgenic L1 expression and behavioural analysis of L1 deficient mice. Dissertation University Hamburg. 2005.
Janssen, Ben J.A., Tijl De Celle, Jacques J.M. Debets, Agnieszka E. Brouns, Michael F. Callahan and Thomas L. Smith. Effects of anesthetics on systemic hemodynamics in mice. Am J Physiol Heart Circ Physiol In press (May 20, 2004)
