Pulse oximetry is a non-invasive method to monitor the oxygen saturation of a patient's blood using a pulse oximeter, which shines red and infrared light through the skin such as a finger to measure changes in light absorption. A pulse oximeter reading between 95-99% is considered normal for a healthy person, while lower readings may indicate issues like lung or circulatory diseases. Immediately after a cardiac arrest, the pulse oximeter will sound an alarm as the pulse is lost and the oxygen saturation decreases.

1. Pulse Oximetry

2. PULSE OXIMETRY DEFINITION: Pulse oximetry is a non invasive method allowing the monitoring of the oxygenation of a patients haemoglobin PULSE OXIMETER DEFINITION: A pulse oximeter is a medical device that indirectly monitors the oxygen saturation of a patient's blood (as opposed to measuring oxygen saturation directly through a blood sample) and changes in blood volume in the skin, producing a photoplethysmograph.

3. Plethysmographic trace (Pleth) Pulse oximeters often show the pulsatile change in absorbance in a graphical form. This is called the "plethysmographic trace” or more conveniently, as "Pleth".

4. How does a Pulse Oximeter Work? The measurements are obtained by simply shining two wavelengths of light (1 is a visible red beam, the other an invisible infrared beam) at e.g. the fingertip.

5. TYPES-OF Pulse Oximeters Desktop Finger/mobile Desktop Finger/mobile

6. Pulse Oximeters may be used in patients: Undergoing surgical procedure under general anesthesia Undergoing surgical procedure under conscious sedation

8. After surgery during the recovery phaseIn the ICU, Pulse Oximetry is used extensively on mechanically ventilated patients

9. Pulse Oximeters may be used in patients: Pulse Oximeters are routinely used in certain hospital wards and in casualty departments for immediate assessment of patients

11. Reduced peripheral pulsatile blood flow

12. Bright overhead lights, such as in an operating theatre

14. The following won’t affect the Pulse Oximeter reading: Anemia Jaundice

15. But what is a "normal" reading? A fit, healthy person should have an oxygen saturation level between 95% & 99%. Results lower than this, and especially below 90% may be caused by problems including lung diseases, such as COPD, breathing difficulties, cigarette smoking or circulatory problems such as excessive bleeding or blood vessel problems.

16. What happens to the pulse Oximeter reading of a patient immediately after a cardiac arrest? The pulse would be lost (causing the alarm to sound) and the saturations will decrease