Welch Allyn Spot Vital Signs Service Manual page 11

Welch Allyn, Inc. Spot Vital Signs Service Manual
Revision A
* Changes in absorption caused by pulsation of blood in the vascular bed are used to determine
arterial saturation and pulse rate. Oxygen saturation percent is calculated with each pulse detected,
and thus the device display is continually updated. The pulse signal bar graph is an indicator of the
strength and quality of the detected pulses.
* The Spot Vital Signs is capable of determining pulse rate as an adjunct to the blood pressure
measurement and the SpO2 measurement.
* The pulse rate, in beats per minute, will be determined primarily from the SpO2 measurement
methodology. In the case where SpO2 is not available, or is disabled, the pulse rate display will be
driven from data collected as part of the blood pressure measurement method.
* Removal of the SpO2 sensor from the patient will initiate an audible beep, to alert the user that the
sensor has been disconnected.
* SpO2 is generally measured via pulses detected using a finger sensor, and performs most accurately
with the finger clip sensor. The finger clip sensor may be used on all fingers except the thumb. For
certain situations SpO2 may be measured at alternate sites including the earlobe, forehead and toes.
Special sensors must be employed in these situations. The finger clip sensor is recommended for spot
checks or short-term evaluation (less than 60 minutes). Patient supervision is required as the Spot
Vital Signs has no alarm capability.
* Oxygen Saturation and pulse rate is displayed on the LCD 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 SpO2 reading. The update interval bar of the bar graph should correspond
to the patient's pulse rate. This is an indication of the quality of the SpO2 signal.
Max/min SpO2 Ranges
The SpO2 sensor is designed to detect oxygen saturation as follows:
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