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.
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.