Measurement of patient & perfusion circuit temperatures including: Types of temperature probes; Temperature range; method of testing the accuracy of temperature probes

1. YSI (Yellow Springs) 43 Tele-thermometer

a) Thermistor probes (Arterial; Nasopharangeal; Tympanic)

b) Dial display

c) Contains potentiometers

d) Battery powered

e) Recalibration:

i) Use of constant water bath at a temperature corresponding to the high range of the instrument (42°C); adjust an internal control so that meter pointer corresponds to bath temperature

ii) Decade resistance block

f) Probe accuracy

i) Should a probe fail completely, the meter pointer will move directly to the right of scale if the probe is shorted; to the let of scale if it is open

ii) Rarely, the base resistance of the probe may change sufficiently to cause the meter reading to be out of specification

iii) If the accuracy of the probe is in question, it should be checked against other probes or a standard of known accuracy

iv) Probe failures are normally irreparable since thermistors are potted & sealed in their assemblies

v) Probe life will vary from a few months to many years depending on the amount of cable flexing

vi) series probes leads can be autoclave or EO

2. Shiley Temperature monitor

a) Thermocouple probes

i) Able to use very small probes eg myocardial with rapid response

b) Digital display

c) Battery powered

d) to 40°C

e) channels; can monitor up to 5 probes simultaneously

f) Calibration

i) Confirm calibration by using a precision glass thermometer in a constant temperature water bath

ii) Must be returned to manufacturer for recalibration

g) Probe accuracy

i) A faulty probe will return a ‘0’ on the display

3. Sarns 8000

a) Thermistor probes

b) Uses YSI 400 type probes

c) - 50°C