Welch Allyn Vital Signs Monitor - User Manual - Manual (Page 15)

Vital Signs Monitor 9
When SpO2 is measured, the patient's pulse rate is also measured and displayed. A pulse rate
measurement from the SpO
2
determination overrides a pulse rate measurement derived from a
blood pressure measurement.
When measuring SpO
2
the user may enable the SpO
2
Pulse Tone feature. A short audible tone is
emitted with every patient heartbeat. The frequency of the tone is based on the patient’s SpO
2
level. The lower the frequency of the tone, the lower the patients SpO
2
level.
In SpO
2
monitoring mode, operator selectable alarm limits for low SpO
2
% may be activated. A
condition which violates the SpO
2
low limit alarm is indicated by a flashing display and repetitive
audible tone. Should a patient alarm condition for SpO
2
or pulse rate occur, the Monitor will indicate
an alarm condition (flashing & beeping) while continuing to monitor and display the patient's current
SpO
2
%. The alarm will automatically reset when the patient's condition returns to within the preset
alarm parameters.
Should a patient alarm condition for SpO
2
or pulse rate occur, the operator may invoke "Silence
Mode" by pressing the SILENCE button. This will silence the audible tone (display will continue to
flash), while the practitioner attends to the patient and the monitor. Silence mode resets automati-
cally after 30 seconds, or when the patient's condition returns to within the preset alarm parame-
ters.
Removal of the SpO
2
sensor from the patient will initiate an alarm, unless the SpO
2
and pulse rate
alarms are turned off. To reset the sensor alarm, press any button on the Monitor's display.
SpO
2
is generally measured via pulses detected using a finger sensor. However, for certain situa-
tions SpO
2
may be measured at alternate sites including the earlobe, forehead and toes. Special
sensors must be employed in these situations.
SpO2 Monitor Mode
The SpO
2
monitor performs most accurately with the fingerclip sensor, which may be used on all
fingers except the thumb. The finger clip sensor is recommended for spot checks or short term
continuous monitoring.
The device determines arterial oxyhemoglobin saturation (SpO
2
%) by measuring the absorption of
red and infrared light passed through the tissue. Oxygen saturation and pulse rate are displayed on
the LED digital display. On each detected pulse, the pulse signal bar graph flashes. The intensity of
this signal is a simple visual indicator of waveform signal strength, and can identify situations where
the pulsatile nature of the tissue may not be adequate for an accurate SpO
2
reading. The update
interval of the bar graph should correspond to the patient's pulse rate. This is an indication of the
quality of the SpO
2
signal.
All Welch Allyn Vital Signs Monitors with pulse oximetry capability are equipped with a pulse tone.
This audible tone beeps in synchronization with each beat of the patient’s heart. In addition, the fre-
quency of the tone will vary based on the patient’s oxygen saturation value. The higher the tone’s
frequency, the higher the patient’s oxygen saturation value. The user may change the pulse tone
volume, or turn this feature off as necessary.