Transonic HT331-FT - Flowsound; Flowmeter Outputs: Connect to Patient Monitor

8 AU-OPR-AureFloFT-EN,
Rev H
1. FLOWSOUND
®
FlowSound
®
provides an audio feedback of volume ow. It is analogous to audio Doppler, but the
sound corresponds to true volume ow, rather than to velocity. The higher the pitch, the higher the
volume ow. An octave increase in pitch corresponds to a 4-fold increase in ow. At zero ow, there is
a low hum sound. The indicator light above the button illuminates when the button is pushed and the
FlowSound
®
function is active. The FlowSound
®
function remains active until the button is pushed
again or the meter is powered off.
TO TEST FLOWSOUND
®
: Connect a Perivascular Flowprobe to the Flowmeter and immerse the Probe’s
head in a container of water. Turn on [FlowSound
®
]. The FlowSound
®
knob on the rear panel can
be used to adjust the sound level. Swish the Probe back and forth in the water and note the changes
in pitch as the volume of ow passing through the Probe’s ultrasonic sensing window changes.
FlowSound
®
is heard only when the ultrasonic signal quality is adequate for ow measurement, i.e. if
the Probe is immersed in water or applied to a vessel without air obstructions.
a) Low Pitch = ZERO or Low ow
b) Higher Pitch = Higher ow
c) No Sound = “NO Signal”: apply gel or saline inside the ultrasonic window
2. FLOWMETER OUTPUTS: CONNECT TO PATIENT MONITOR
There is one analog output on the rear panel of the Single Channel Meters and two on the Dual
Channel Meters. The voltage levels of these ow signals follow Transonic
®
Uniscale convention
to simplify connection to commercial intraoperative Monitors. The Uniscale is scaled according to
Flowprobe size:
PROBE DESCRIPTION PROBE SIZE SENSITIVITY AT 1X
Small Probes 0.7 - 6 size 1 Volt = 200 mL/min
Medium Probes 7 - 14 size 1 Volt = 4 L/min
Large Probes 16 - 36 size 1 Volt = 20 L/min
Therefore, when the [Flow Scale] rear panel button is momentarily depressed during normal ow
measurement:
a) Voltage on the rear panel output and USB port is switched to + 1 Volt for 10 seconds, then to 0 Volt
for 10 seconds.
b) The front panel Meter Display will simultaneously indicate the corresponding ow levels: First, the
Flowprobe’s Uniscale level of 1 Volt (200 mL/min, 4L/min or 20L/min) and then “0 mL/min” (0 Volt).
(With [Sensitivity] switch set at 1x.)
The Uniscale voltage output for a given real ow displayed on the front panel can be multiplied by a
factor of 2 or 4 by switching the [Sensitivity] switch from 1x to 2x or 4x which corresponds to 1V, 2V
and 4V respectively.
EXAMPLE OF UNISCALE SENSITIVITY
A cardiac surgeon routinely uses a 2, 3 or 4 mm Flowprobe in CABG surgery and wants to see the real-
time ow curves displayed on the central patient Monitor. Although each of these Flowprobe sizes has
a different scale factor, the Uniscale output has automatic gain adjustment, so 1 Volt = 200 mL/min, no
matter which Flowprobe size is used. If the scaling of the waveform is not appropriate, (e.g. for increased
resolution of low ows) it can be adjusted using the [Sensitivity] switch.
Functions & Controls