Pulse Oximetry:

Procedure: Pulse Oximetry is a safe and  simple method of assessing oxygenation. An  advantage is  that this method  is noninvasive and continuous. Previously, the most  common method of assessing oxygenation was  the use of arterial blood gases. Pulse Oximetry was originally used  in surgery. The pulse oximeter passes a beam of  light through the tissue, and a sensor attached  to  the fingertip,  toe, or ear lobe measures the  amount of  light absorbed by  the oxygen- saturated hemoglobin. The oximeter then gives a reading of the percentage of hemoglobin that  is saturated with  oxygen. Saturated oxygen has a close relation with  the saturations obtained  from the pulse oximeter if  it  is above 70 per cent. The  table below provides a quick guide for comparison of saturated oxygen and partial pressure of arterial oxygen. 

Nurses'  Responsibility:

The nurse should continue to assess the whole patient and not just  the oxygen saturation monitor. If values fall below preset norms, (usually 90 per cent) the client shonld be  instructed to deep breathe (if appropriate). Sometimes the amount of inspired oxygen  is  increased(titrated) to keep oxygen saturation above 90 per cent. Instruct the client that  an infrared light probe will be attached  to a finger, toe,  or ear lobe. The client should avoid moving the  sensor because movement disrupts the sensor and gives false readings.