Wednesday, July 8, 2020

PULSE OXIMETER

Hi friends!!!

In our previous blog we have discussed about Endoscope Machine. Please check out for the link below.


Today we are going to discuss about Pulse Oximeter. Pulse Oximeter is a important device used to monitor blood oxygen saturation level. Therefore it is important for every healthcare professional to know in detail about Pulse Oximeter.

Let's get into the topic.

WHAT IS PULSE
OXIMETER?

Pulse Oximeter is a small clip like device which is usually attached to body parts like toes, earlobes and mostly on fingers. Pulse Oximeter usually measures blood oxygen saturation level which means it checks how well your heart is pumping oxygen through the body. It detects even a small change in efficiency of how oxygen is carried to the other extremes of the body. It also measures the heart rate.


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WHAT IS OXYGEN SATURATION?

After entering the lungs, oxygen is passed onto the blood. Oxygen is carried through our blood with the help of hemoglobin in the blood to the other extremities of the body. Here hemoglobin which carries oxygen is called oxygenated hemoglobin and hemoglobin which does not carry oxygen is called deoxygenated hemoglobin. Oxygen saturation is the measure of percentage of available hemoglobin that carries oxygen. 


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WHAT IS THE
TECHNOLOGY USED?

Pulse Oximeter works on the property that oxygenated hemoglobin and deoxygenated hemoglobin absorb light differently at different wavelength. Pulse Oximeter consists of two pair of Light Emitting Diodes at the one end and detector (Photo Diode) at the other end. One LED is red with a wavelength of 660 nm and other LED is infrared with a wavelength of 940 nm. 

Absorption of these lights varies with respective to the blood with high oxygen and blood lacking oxygen. Oxygenated hemoglobin absorbs more infrared light and passes more red light through it. De-oxygenated hemoglobin absorbs more red light and allows more infrared light to pass through it. Pulse Oximeter measures oxygen saturation by comparing the level of absorption of red and infrared light.


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Light absorption also depends upon the amount of light absorbing substances, that is oxygenated hemoglobin and Light absorption also depends upon the length of the path in which the light travels.

WHAT ARE THE
CHALLENGES?

Blood is not the only thing that absorbs light in the fingers. There are other nearby tissues and skin surface which also absorbs light. The main challenge for pulse oximeter is that it should differentiate the volume of light absorbed by blood and volume of light absorbed by other surrounding tissues.

This differentiation can be done based on the following property. The blood is the only thing that is pulsating, which means arterial blood has difference in absorbance of light. And the surrounding tissues and skin are non pulsating, which means they have same level of absorbance. Based on this, the pulse oximeter segregates the absorbance of light by blood, thus eliminating the same level of absorbance from the total absorbance.

WHAT ARE THE USES OF PULSE OXIMETER?

1. To monitor whether patients momentarily stops breathing while sleeping, like sleep apnea
2. To find out whether someone needs help in breathing.
3. To monitor oxygen levels during and after surgical procedures that require sedation.
4. To check a persons ability to increased physical activity.

NOTE: Blood Oxygen Saturation level between 90 to 100 percent indicates the healthy level of oxygen carrying hemoglobin in the blood. It also indicates a healthy condition of heart and lung.

Now I hope you have acquired some knowledge about Pulse Oximeter. We will discuss about topics related to Biomedical Engineering, Medical Devices, Healthcare in our next blog.

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1 comment:

  1. Very good, this topic totally refreshed my knowledge on pulse oximeter

    ReplyDelete