Measurement Principle - Braun Pulse oximeter 1 Manual De Instrucciones

that combines with the hemoglobin is determined by
the partial pressure of oxygen. The amount of oxygen
in blood, expressed as a percentage of hemoglobin
saturation is a measure of oxygen (SaO2) in the artery and
is estimated by a pulse oximeter as an SpO2 reading.
The amount of oxygen in blood (as measured by the pulse
oximeter SpO2 reading) is a very important physiological
parameter in respiratory and circulatory systems. Many
respiratory diseases reduce the oxygen-hemoglobin
saturation in human blood. Moreover, factors such
as Automatic Organic Regulation Malfunction caused
by anesthesia, trauma resulting from major surgery or
medical examination, or other diseases due to virus or
bacteria can also cause a reduction in oxygen hemoglobin
saturation in arterial blood which can be detected by the
pulse oximeter through a low SpO2 reading. This can
result in symptoms such as depression, vomiting, and
asthenia in patients.
The fingertip pulse oximeter is a compact, low-power
consumption, portable device. When the index finger
is inserted into the fingertip photoelectric sensor, the
display screen of the Braun Pulse oximeter will show the
measured value of %SpO2 and pulse rate as well as a
vertical bar graph showing the pulse amplitude.

Measurement principle

Pulse oximetry is based on the difference in the
selective absorption of red light by oxygenated blood or
oxyhemoglobin (HbO2, which is bright red) as compared
to deoxyhemoglobin (Hb, which is dull red) or de-
oxygenated blood. This selective absorption is based
on the Beer Lambert Law. A red (660nm) and infrared
LED (940nm) on the top portion of the prospective clamp
finger-type sensor emits light at these two frequencies.
The red light transmitted through the finger is selectively
absorbed by the oxygenated arterial blood and the
remaining light is detected by a photodetector on the
lower portion of the clamp finger. The infrared light
then passes through the finger without any selective
absorption and is detected by the photodetector on the
lower side of the clamp. The transmitted light captured by
the photodetector is converted into a voltage or current
signal and then passed through signal conditioning and
filtering circuits using a microprocessor. %SpO2 is then
derived by analyzing the changes in the amplitude of
these pulsatile signals derived from the photodetector
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