Welch Allyn Atlas Operator's Manual page 57

Blood pressure measurements – Blood
pressure cycling can be scheduled automatically
or started manually, as determined by the choice
selected by the button. When you turn on
Auto
the monitor, the
Auto
but it remembers the previous setting. Press the
button once to return to the previous
Auto
setting, or press it repeatedly to select a new
interval. Or choose "X" for manual operation.
Wait 10 seconds for the selected Auto value to
stop flashing. If any value other than "X" is
selected, the first automatic measurement will
begin 20 seconds after the Auto LED stops
flashing.
If you press
BP Start/Cancel
automatically timed measurements, the cuff will
begin to inflate immediately and the monitor
will record a new set of measurements. The
manual measurement will not interfere with the
automatic timing unless the next automatic
measurement is scheduled to occur within 30
seconds of the end of the manual measurement.
Pressing
BP Start/Cancel
pressure measurement will cause the cuff to
deflate immediately, and the reading is canceled.
The trend data for that reading will show as
dashes "---" on the screen and in the printout.
Both Systolic and Diastolic blood pressures are
displayed on the front panel. During
measurement, the Systolic display shows the
cuff pressure as it pumps up and steps down.
Mean Arterial Pressure (MAP) is displayed on
the screen (upper left) only if it is enabled in the
Advanced Configuration menu.
Note: If the language setting is configured to
Chinese, you can configure the Alternate BP
field to display MAP or blood pressure in
kPa on the screen (upper left).
Note: MAP is calculated using the formula: one
third of the Systolic reading plus two thirds
of the Diastolic reading.
Principles of Operation – The Atlas Monitor
setting defaults to "X",
between
during a blood
uses an 'oscillometric' method to measure the
patient's blood pressure. This technique is
characterized by inflating the blood pressure
cuff until the arterial blood flow is occluded, and
then slowly releasing the cuff pressure and
monitoring the oscillations in the cuff air
pressure due to arterial blood flow pulses. While
the cuff is deflating, the amplitude of the
oscillations are recorded versus cuff pressure.
The systolic measurement is found by noting the
cuff pressure when the pre-maximum
oscillations are at a fixed percentage of the
maximum oscillations. Similarly, the diastolic
pressure is found by noting the cuff pressure
when the post-maximum oscillations are at a
fixed percentage of the maximum oscillations.
If the initial cuff pressure is insufficient to
occlude the arterial blood flow, the instrument
will re-inflate the cuff by approximately 40
mmHg. During deflation, the instrument may
also re-inflate in order to re-measure the
oscillations.
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