Product Manual

M3A Vital Signs Monitor User Manual SpO
2
Monitoring (Optional)
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Chapter 9 SpO
2
Monitoring (Optional)
9.1 What is SpO
2
Monitoring
The monitor uses oximetry to measure functional oxygen saturation in the blood. SpO
2
Plethysmogram measurement is employed to determine the functional oxygen saturation of
hemoglobin in the arterial blood. For example, if 97% hemoglobin molecules in the red blood
cells of the arterial blood combine with oxygen, then the blood has an SpO
2
oxygen saturation of
97%. The SpO
2
numeric on the monitor will read 97%. The SpO
2
numeric shows the percentage
of hemoglobin molecules which have combined with oxygen molecules to form oxyhemoglobin.
The SpO
2
/PLETH parameter can also provide a pulse rate signal and a plethysmogram wave.
How the SpO
2
/PLETH Parameter Works
■ Arterial oxygen saturation is measured by a method called pulse oximetry. It is a continuous,
non-invasive method based on the different absorption spectra of reduced hemoglobin and
oxyhemoglobin. It measures how much light, sent from light sources on one side of the
sensor, is transmitted through patient tissue (such as a finger or an ear), to a receiver on the
other side.
■ The amount of light transmitted depends on many factors, most of which are constant.
However, one of these factors, the blood flow in the arteries, varies with time, because it is
pulsating. By measuring the light absorption during a pulsation, it is possible to derive the
oxygen saturation of the arterial blood. Detecting the pulsation gives a PLETH waveform
and pulse rate signal.
■ The SpO
2
value and the PLETH waveform can be displayed on the main interface.
■ The sensor contains LEDs that emit red light at a wavelength of approximately 660 nm and
infrared light at a wavelength of approximately 900 nm. The power of the sensor LED is less
than 15 mW.
SpO
2
/Pulse Monitoring
WARNING
1 ES (Electrosurgery) equipment wire and SpO
2
cable must not be tangled up.
2 Do not put the sensor on extremities with arterial catheter or venous syringe.
3 Pulse oximetry can overestimate the SpO
2
value in the presence of Hb-CO, Met-Hb
or dye dilution chemicals.
NOTE:
1 Do not perform SpO
2
measuring and NIBP measuring on a same arm at one time,
because obstruction of blood flow during NIBP measuring may adversely affect the
reading of SpO
2
value.
2 The monitor should not be used under strong light, or the accuracy may not be
satisfied.