16 Monitoring tcGas
Setting the tcGas Sensor Temperature
Choose a temperature value appropriate for your patient's age, weight and physical condition in
accordance with your hospital policy.
Usually, a higher transducer temperature gives a better correlation and a quicker response time.
However, higher temperatures also increase the risk of skin burns. Most physicians prefer a
temperature between 42°C (107°F) and 44°C (111°F), and a site time of four hours or less. Usually,
the higher the transducer temperature, the less the site time should be. Whenever you change the
temperature setting, the monitor forces you to make a new calibration.
Using the tcGas Site Timer
Availability and behavior of the site timer depend on your monitor's configuration.
Prolonged continuous monitoring may increase the risk of undesirable changes in skin characteristics,
such as irritation, reddening, blistering or burns. If the site timer is disabled, the transducer will heat
indefinitely while on a patient. Change the site regularly, in accordance with medical procedures in your
Setting the tcGas Site Timer
The site timer helps reduce the risk of skin burn by ensuring that the transducer is used at one site for
no longer than a predefined period. It reminds you when this period expires.
Choose the time you want the transducer to remain on the measurement site. The optimum time
depends on the transducer temperature and your patient's skin sensitivity.
The site timer starts automatically when you remove the calibrated transducer from the calibration
chamber. If you return the transducer to the chamber and then remove it again, the site time continues
to count down the remaining time; it does not start a new time period. The time remaining before the
site timer expires appears in the status line which is visible as long as the
When the time expires, the monitor sounds a tone and a displays a change site INOP. The monitor
either switches off the transducer heating or continues monitoring, depending on its configuration.
Although you can reuse the transducer for up to two hours after the heating is switched off, without
making a new calibration, you are recommended to recalibrate before applying it to a patient. After two
hours without heat, you must recalibrate.
During the initial few minutes of use, the monitor eliminates false alarms by temporarily suppressing
tcGas alarms. It displays the
skin, the instrument reading slowly assumes a steady value. The reading stabilizes when the
measurement site is warm and local hyperemization is complete. This takes 10 to 20 minutes for the
reading and three to seven minutes for tcpCO
<tcGas Label> Stabilizing
INOP. After you apply the transducer to the
menu is open.