User guide

Chapter 4: Measurements and Calculations 67
Measurements
author for the OB tables, which you choose on a system
setup page, determines the measurements you must
perform to obtain an EFW calculation. (See “OB
Calculations setup” on page 20.)
Individual selections for Hadlock’s EFW equations 1, 2, and 3
are not determined by the user. The selected equation is
determined by the measurements that have been saved to
the patient report with priority given to the order listed
above.
d. The Growth Analysis tables are used by the Report Graphs
feature. Three growth curves are drawn using the table data
for the selected growth parameter and published author.
Growth tables are only available with a user-entered LMP or
Estab. DD.
To measure gestational growth (2D)
For each 2D OB measurement (except AFI), the
system saves up to three individual measurements
and their average. If you take more than three
measurements, the earliest measurement is
deleted.
1 In the patient information form, select OB exam
type, and select LMP or Estab.DD. Select
Twins if appropriate.
2 On a frozen 2D image, press the
CALCS key.
3 Do the following for each measurement you
want to take:
a From the calculations menu, select the
measurement name. For twins, select
Twin A or Twin B, and then select the
measurement name.
The caliper tool may change depending on
the measurement selected, but the position
remains constant.
b Position the calipers. (See “Working with
calipers” on page 43.)
c Save the calculation. (See “To save a
calculation” on page 47.)
To measure fetal heart rate (M Mode)
1 On a frozen M Mode trace, press the CALCS key.
2 Select FHR from the calculations menu.
A vertical caliper appears.
3 Using the touchpad, position the vertical caliper
at the peak of the heartbeat.
4 Press the
SELECT key.
A second vertical caliper appears.
5 Using the touchpad, position the second vertical
caliper at the peak of the next heartbeat.
6 Save the calculation. (See “To save a
calculation” on page 47.)
To calculate MCA or Umba (Doppler)
Note: The system does not provide an
MCA/UmbA ratio from the PI (Pulsatility Index).
1 Select OB exam type, and select LMP or
Estab.DD in the patient information form.
2 On a frozen Doppler spectral trace, press the
CALCS key.
3 Do the following for each measurement you
need to take:
a From the calculations menu, select the
measurement name under MCA (Middle
Cerebral Artery) or UmbA (Umbilical
Artery).
OB Doppler Calculations
Menu
Heading
OB
Calculation
Results
MCA (Middle
Cerebral
Artery)
S/D, RI
SD
RI
S/D, RI, PI*
SD
RI
PI
Umb A
(Umbilical
Artery)
S/D, RI
SD
RI
S/D, RI, PI*
SD
RI
PI
*Calculation requires a trace measurement.