Pulseoximeter and Plethysmography by Pandian M

Aim

Principle

Apparatus

Procedure

Precaution

1. Plethysmography Pandian M Dept of Physiology DYPMCKOP

2. Aim Principle Apparatus Procedure Precaution

3. Plethysmography A plethysmograph is an instrument for measuring changes in volume within an organ or whole body

4. What Is Plethysmography? Plethysmography measures changes in volume in different areas of your body. It measures these changes with blood pressure cuffs or other sensors. These are attached to a machine called a plethysmograph .

5. Plethysmography is especially effective in detecting changes caused by blood flow. It can help your doctor determine if you have a blood clot in your arm or leg. It can also help your doctor calculate the volume of air your lungs can hold.

6. When Is Plethysmography Ordered? Your doctor may order a limb plethysmography if you show signs of blood clots in your legs. Symptoms of blood clots include redness, warmth, swelling, and tenderness . Plethysmography is not as accurate as an arteriogram, which is more commonly used to identify blood clots . But it’s non invasive and less expensive . These factors make it more appealing to many individuals.

7. You doctor may order a lung plethysmography if you have symptoms of upper respiratory problems. These symptoms include pain or discomfort while breathing and shortness of breath. Your doctor can’t diagnose the underlying cause of your problem from plethysmography alone. However , an abnormal test result can confirm if something is preventing your lungs from holding as much air as they should.

8. Types of Plethysmography Limb Plethysmography Lung Plethysmography

9. Procedure for a Plethysmography Limb Plethysmography A limb plethysmography can be performed in a doctor’s office or hospital. If you’re wearing pants or a long-sleeved shirt, your doctor will ask you to undress and put on a hospital gown. They’ll ask you to keep one leg and one arm bare. You will recline in a comfortable position on an examination table, cot, or gurney. Your doctor will then place blood pressure cuffs on your leg and arm .

10. They’ll be most interested in checking your systolic blood pressure. That’s the pressure of blood in your arm and leg when your heart contracts. You may feel a little uncomfortable when the blood pressure cuffs tighten around your arm and leg, but you won’t feel any real pain. The test usually lasts about 20 to 30 minutes. During this time, you’ll be asked to move as little as possible. Limb plethysmography is not associated with any risks or side effects. Unless your doctor tells you otherwise, you can resume your regular schedule immediately after the test.

11. Lung Plethysmography A lung plethysmography can be performed in a specialist’s office or in a hospital. You will sit in a small, airtight room. Your doctor will use clips to close off your nostrils. Then they’ll ask you to breathe against a mouthpiece. Some people report becoming short of breath or lightheaded. Let your doctor know if you experience these symptoms during the test. Unless your doctor tells you otherwise, you can resume your regular activities immediately after the test.

12. Interpreting the Tests Limb Plethysmography Normally, the systolic blood pressure in your arm and leg are similar. The ankle-brachial index (ABI) is a measurement used to check for potential problems. To calculate your ABI, divide the highest systolic blood pressure reading from your leg by the highest reading from your arm. A normal ABI falls between 0.90 and 1.30, according to the  National Heart, Lung, and Blood InstituteTrusted Source . If your ABI falls outside this range, you may have a narrow or blocked artery. Your doctor can order additional tests to determine the exact nature of the problem.

13. Pulse Oximeter used to measure oxygen saturation in the body i.e how much of the hemoglobin in the blood is carrying the oxygen.

14. Oxygen enters the lungs and then is passed on into blood. The blood carries the oxygen to the various organs in our body. The main way oxygen is carried in our blood is by means of hemoglobin. Normal oxygen saturation values are 97% to 99% in a healthy individual on room air.

15. Ratio of saturation:

16. Oxygenated and deoxygenated hemoglobin have different light absorption rate. * Oxygenated hemoglobin absorbs more infrared light * Deoxygenated hemoglobin absorbs more red light Pulse Oximetry consists of Red(R) and Infrared(IR) light emitting LEDs and a photo detector.

17. Finger is placed in between the light source and the light detector. Non absorbed light by finger reaches at detector. Light is emitted from light sources which goes across the pulse oximeter probe and reaches the light detector.

18. The amount of light absorbed depends on three physical properties: 1. concentration of the light absorbing substance. 2. length of the light path in the absorbing substance 3. oxyhemoglobin and deoxyhemoglobin absorbs red and infrared light differently

19. Amount of light absorbed is proportional to the concentration of the light absorbing substance.

20. Amount of light absorbed is proportional to the length of the light path.

21. oxyhemoglobin absorbs more infrared light than red light & deoxyhemoglobin absorbs more red light than infrared light.

22. Using this ratio, the pulse oximeter can then work out the oxygen saturation.

23.          Operating rooms ICU Postanesthesia care units Emergency departments and ambulances Endoscopy suites Sleep laboratories Cardiac catheterization laboratories Delivery suites Wards

24. Pulse Oximeter

25. Precaution

26. Reference Textbook of Practical Physiology A.K. Jain C.L. Ghai G.K.Pal Textbook of Medical Physiology By Guyton & Hall, A.K. Jain Net sources

27. THANK YOU . . .