ABSTRACT
Now a day Pulse Oximeter is a very important instrument in the surgical or intensive
care units, as it's a very fast and real time indication to the blood oxygen saturation
level, which gives an indication of the patient's status. Its theory of operation mainly
depends on the phenomena of difference in the absorption of different wavelengths
by body tissues and blood constitutes. The raw Pulse Oximeter (plethysmography)
signal undergoes a lot of processing to calculate the desired values of the Blood
Oxygen saturation .Many methods are employed either in time domain analysis or
through frequency domain analysis. Each Method has its own advantage and
disadvantage. By combining all these methods into a hybrid algorithm of processing
taking into consideration the limitations and the most important advantages in each
method, it is applicable to have an accurate method of calculating the SaO2.