Welch Allyn TM 262 Auto Tymp - User Manual - Manual (Page 30)

TM 262
2-12 Revised 4/11/08
PreTest Tymp checks
For your convenience, a test cavity is provided with your instrument. This test cavity enables
you to quickly verify, on a daily basis, the proper calibration of your unit. Welch Allyn strongly
recommends that you make this quick check a part of your daily routine.
Calibration
NOTE: To initiate the quick check, select the Tymp only mode and insert the probe into the
0.5 cm 3 opening on the test cavity. See Figure 12.
Figure 12: Test cavity
NOTE: Since the instrument is designed to start automatically, it is important that the probe is
inserted as quickly and as smoothly as possible. During the calibration check, the probe must be
held carefully and without movement. Do not place the probe on the same counter as the
instrument or any moving object during this check as mechanical noise will be picked up by the
probe and interfere with the calibration check.
The calibration check will start automatically if the probe has been inserted into the cavity
properly. This is confirmed by the green lamp changing from blinking to a steady condition. If
If the orange lamp is illuminated, the probe is not properly positioned within the cavity so that
a large pressure leak exists. If the yellow lamp is illuminated, the probe tip has been occluded.
In either case, remove the probe and wait for the blinking green lamp. Insert the probe once
again. If necessary, clean the probe tip as described in Chapter 3.
When the test sequence is completed, the green lamp on the probe is no longer illuminated.
Remove the probe from the test cavity and note that the green lamp is blinking once again. The
display will indicate a flat line on the tympanogram along with the value of the test cavity next
to the letters ECV (ear canal volume) i.e., 0.5. The letters NP will appear next to the labels cm
and daPa and three dashed lines will appear next to the letters GR (gradient). Since the test
cavity is a hard-walled cavity, the tympanogram should be a fiat line indicating that there is no
mobility in the system. The instrument places the letters NP next to the cm and daPa headers to
indicate that there is no peak compliance and, therefore, no peak pressure can be determined
during the quick check. Also, since there is no compliance peak detected, it is not possible to
calculate a gradient. Therefore, the instrument displays the dashed lines when a gradient
calculation is not possible. Using the same sequence, place the probe in the test cavity opening
labelled 2.0 cm
3 . Note that the display looks the same as with the 0.5 cm 3 measurement except
for the value placed next to the letters ECV 2.0. If you wish, the same sequence can be followed