User guide

Chapter 4: Measurements and Calculations 61
Measurements
1 (CI Only) Fill in the Height and Weight fields on
the patient information form. The BSA is
calculated automatically. (See “To create a
new patient information form” on page 36.)
2 Calculate SV. See “To calculate Stroke
Volume (SV) or Stroke Index (SI)” on
page 60.
3 Calculate HR. See “To calculate Heart Rate
(HR)” on page 60.
To calculate Cardiac Output automatically
1 Make sure that the flow rate is 1 L/min or
greater.
The system can maintain accuracy of the
measurements only if the flow rate is 1 L/min or
greater.
2 Measure from LVOT (2D):
a On a frozen 2D image, press the
CALCS key.
b From the calculations menu, select CO, and
then select LVOT D.
c Position the calipers. (See “Working with
calipers” on page 43.)
d Save the calculation. (See “To save a
calculation” on page 47.)
3 Trace automatically (Doppler):
The automatic trace tool always measures the
peak regardless of the Live Trace setting in
Presets setup.
a Display the Doppler spectral trace
(waveform).
b Select Trace on-screen, and then select
Above or Below for the position of the
automatic trace tool relative to the baseline.
The automatic trace tool appears in yellow.
The results appear at the bottom of the
screen.
c Freeze the image.
If you want to change the waveform
measured, move each vertical caliper by
pressing
SELECT and then using the
touchpad. Press
SET to update the results.
If you invert the frozen image or move the
baseline, results are cleared.
If you want to hide the results, select Trace.
d Save the calculation.
To measure a Tissue Doppler Imaging
(TDI) waveform
1 Ensure that TDI is on. (See “PW Doppler
controls” on page 29.)
2 On a frozen Doppler spectral trace, press the
CALCS key.
3 From the calculations menu, select TDI, and
then do the following for each measurement
you want to take:
a From the calculations menu, select the
measurement name.
b Position the calipers. (See “Working with
calipers” on page 43.)
WARNING:
To avoid incorrect calculation
results, make sure that the Doppler
signal does not alias.
WARNING:
To avoid an incorrect diagnosis:
• Do not use automatic Cardiac
Output calculations as the sole
diagnostic criteria. Use them only
in conjunction with other clinical
information and patient history.
• Do not use automatic Cardiac
Output calculations in neonatal
patients.
WARNING:
To avoid inaccurate velocity
measurements if you use PW
Doppler, make sure that Angle
Correction is set to zero.