Patient Monitor User’s manual
9-1
Chapter 9 SpO
2
9.1 Introduction
The measurement of oxygen saturation of arterial blood (also known as pulse
oxygen saturation, usually shortened as SpO
2
) adopts the principles of light spectra
and volume tracing. The LED emits lights with two specific wavelengths, which are
selectively absorbed by oxygenated hemoglobin and deoxyhemoglobin. The optical
receptor measures the changes in the light intensity after the light passes the capillary
network and estimates the ratio of oxygenated hemoglobin and the total hemoglobin.
The SpO
2
sensor measurement wavelengths are nominally 660nm for the Red
LED and 940nm for infrared LED
9.2 Safety Information
Warning:
Use only SpO2 sensors specified in this manual. Follow the SpO2 sensor’s
instructions for use and adhere to all warnings and cautions.
When a trend toward patient deoxygenation is indicated, blood samples
should be analyzed by a laboratory co-oximeter to completely understand
the patient’s conditions.
Do not use the monitor and the SpO2 sensor during magnetic resonance
imaging (MRI). Induced current could cause burns.
Prolonged continuous monitoring may increase the risk of unexpected
changes in skin characteristics, such as irritation, reddening, blistering or
burns. Inspect the sensor site every two hours and move the sensor if the skin
quality changes. For neonates, or patients with poor peripheral blood
circulation or sensitive skin, inspect the sensor site more frequently.
Warning:
Check the SpO2 sensor and its package for any sign of damage before use.
SpO
2
%
=
100%
oxygenated hemoglobin
oxyhemoglobin + deoxyhemoglobin