Rad-5/5v
Chapter 1: Technology Overview
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16
Masimo
Masimo SET
®
DST
This figure is for conceptual purposes only.
General Description for Oxygen Saturation (SpO2)
Pulse oximetry is governed by the following principles:
1.
Oxyhemoglobin (oxygenated blood) and deoxyhemoglobin (non-oxygenated
blood) differ in their absorption of red and infrared light (spectrophotometry).
2.
The amount of arterial blood in tissue changes with your pulse
(photoplethysmography). Therefore, the amount of light absorbed by the varying
quantities of arterial blood changes as well.
Successful Monitoring for SpO2 and PR
Stability of the SpO
2
readings may be a good indicator of signal validity. Although stability
is a relative term, experience will provide a good feeling for changes that are artifactual or
physiological and the speed, timing, and behavior of each.
The stability of the readings over time is affected by the averaging mode being used. The
longer the averaging time, the more stable the readings tend to become. This is due to a
dampened response as the signal is averaged over a longer period of time than during
shorter averaging times. However, longer averaging times delay the response of the
oximeter and reduce the measured variations of SpO
2
and pulse rate.
The following general points will aid in ensuring oximetry monitoring success.
Place the sensor on a site that is not too thick, has sufficient perfusion and
provides proper alignment of the LEDs and detector.
Place the sensor on a site that has unrestricted blood flow.
Do not constrict the monitoring site when securing a sensor with tape.
Do not select a site near potential electrical interference (electrosurgical unit, for
example).
Read the sensor Directions for Use for proper sensor application.
