20
Blood FlowMeter
Owner’s Guide
Probe Application
Warning:
Needle (implantable) laser Doppler probes are ONLY for use in
animals. Only surface laser Doppler probes are safe for use on humans.
Surface probes can be attached to tissue using a self adhesive ring. Th
ese have
adhesive on both sides with a small hole in the center. Needle probes can be
secured by using a micro-manipulator or some similar device.
It is important to control the relative movements of the tissue (especially that
induced by breathing) with respect to the probe. Relative movements will
produce artifacts in the perfusion signal. Th
ese can be reduced by allowing
the supported probe to lightly contact the surface of the tissue. Under some
conditions it may be desirable for the probe to be held in position by hand.
It is essential to ensure that the pressure on the tissue is minimal, otherwise
local occlusion of the microvasculature may result.
Excessive ambient lighting at the probe site can disturb the blood perfusion
reading. Avoid direct illumination of the measurement site, especially
direct sunlight. If erroneous readings of the measurement site from external
lighting levels are suspected, cover the attached probe and measurement area
with a light piece of opaque material.
Probe signal outputs for diff erent conditions are listed in Table 2–1.
Condition
LDF
Backscatter
No probe
-2.5 V (-2500 BPU)
0 V (0 %)
Unrecognized probe
-5 V (-5000 BPU)
-5 V (-100 %)
Low backscatter
0 V (0 BPU)
-2.5 V (-50 %)
Flow over range
+5 V (+5000 BPU)
+ 5 V (+100 %)
Temperature Warning
If the internal temperature of the Blood FlowMeter moves outside the
operating temperature range of the device, then it will emit a double beep
every 16 seconds. If this occurs, the instruments should be moved to a cooler
environment for proper operation.
With the temperature out of range, output signals will continue to be
generated but may no longer be within the calibrated tolerance of the system
and should be interpreted with caution. If there are any problems or faults
please contact your ADInstruments representative for further advice.
Table 2–1
Probe outputs for
different conditions
