How to Analyze O2 Saturation

The most common location for oximetry is the index finger.

A pulse oximetry meter is one of the most popular and noninvasive machines used in critical care. It helps give an idea of how much oxygen is in the blood as well as the heart rate. While there many human variables that can alter the reading, it is a relatively easy machine to use and understand. The machine has light probes to measure O2 stats and clips that can attach anywhere there is an arterial pulse. The most common places are fingers, toes, nose and earlobes.

Things You'll Need

• Pulse Oximetry Meter and associated attachments (probes, cables and power source)

Instructions

Oximetry Evaluation

1. Check an area of the body for warmth and presence of a blood flow or pulse. Areas that are too cold or do not have a pulse will yield errors in reading.

2. Select and fit an appropriate-size sensor and probe to the machine and place them on the selected body site. Make sure the sensor and light probe are lined up with each other and are not crooked.

3. Plug the cable from the sensor into the oximetry meter and make sure the machine is on and functioning.

4. Ensure that the probe is not cutting off blood flow to the area, which can happen if it is too tight a fit.

5. 

   The radial pulse is on the inner wrist below the thumb.

   Double-check the accuracy of the machine by comparing a manual pulse rate to the meter's pulse rate. Pulse rate can be checked by counting the number of beats against gloved fingers (not the thumb) with the radial pulse (inside of the wrist on the thumb side) or carotid pulse (either side of the neck, just under the jaw line).

6. Look at the Sp02 number if the machine is producing an accurate pulse rate. This number indicates O2 saturation. If the machine is not accurate with the pulse rate, the SpO2 number will be off as well.

7. 

   Oxygen supplementation is the first thing given for hypoxia.

   Check for normal O2 saturation, between 95 to 98 percent. Less than 95 percent indicates circulation compromise. Less than 90 percent is severe oxygen compromise (hypoxia). Oximetry meters do not give an accurate reading below 70 percent saturation. If the levels are that low, signs of hypoxia (i.e. blue skin) will be visible to the naked eye and need immediate treatment.

8. 

   Nail polish can interfere with the light probes.

   Rule out human error before treatment begins. Make sure the person being monitored is not moving, and the body and appendage being monitored is warm and does not have nail polish or anything to interfere with the light probe. People with anemia will also have altered SpO2 levels.

9. Once all human error has been ruled out, continue to monitor vitals if normal or treat for hypoxia if below normal.

Tips & Warnings

• Local firefighter and EMT departments can show families how to use oximetry meters.

• -- The oximetry meter is just a tool to help monitor vital signs, so never let what the meter shows override common sense.

• -- If using at home and showing signs of hypoxia, call 911 for further help.

References

• AACN Procedure Manual for Critical Care, Fourth Edition" Saunders, W.B.; 2001
• Indiana Department of Homeland Security: EMS Oximetry
• "Update in Anesthesia;" Pulse Oximetry.; Fearnley, SJ.; 1995