Pulse oximetry.

THIS IS A PPT ON PULSE OXIMETRY .

1. PULSE OXIMETRY Akash Sardar Student(4 th Year) Bio Medical Engineering Dept.

2. Introduction The first oximeter was introduced by Karl Matthews –in the year 1935. First oximeter to measure O2 saturation. Dr. Takuo Aoyagi (1972) Pulsatile changes in absorption of red and infra-red light to measure arterial oxygen saturation.

3. Pulse- Oximeter A pulse-oximeter measures the amount of saturated oxygen in blood. It is a non-invasive method. It depends on The combination of both Beer’s Law and Lambert’s Law.

4. Beer-Lambert Law The combination of both Beer’s Law and Lambert’s Law Beer-Lambert’s Law – The absorption of light is proportional to the concentration and thickness of the sample.

5. THE INSTRUMENT

6. Principles Pulse oximetry is based on the differential absorption of light by oxyhemoglobin and deoxyhemoglobin. The oxygenated blood absorbs red light while the deoxygenated blood absorbs infrared light.

7. Principles Pulse oximeter consists of two light emitting diodes at 660nm& 940nm . Isobestic point.

8. Block diagram

9. Procedure A photo detector in the sensor measures unabsorbed light from the LEDs.

10. Procedure The resulting signal is inverted and resembles as per the diagram below.

11. BLOOD CONCENTRATION

12. factors effecting the pulse oximeter reading Major body motion . Blood flow blocked due to pressure on arms or fingers . Probe attached incorrectly . Excessive ambient light (panel lamp, fluorescent lamp, infrared heating lamp, direct sunlight, etc.)

13. purpose of the pulse oximeter Screening for sleep apnea syndrome. Hospitalization of patients with chronic respiration diseases. If a patient’s blood oxygenation is unstable. Home oxygen therapy.

14. Thank You