Pulse Oximetry
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Pulse Oximetry: Understanding and Application
Introduction to Pulse Oximetry
Pulse oximetry is a vital tool for measuring oxygen saturation in arterial blood, providing critical insights into patient health without invasive procedures.
Benefits of Pulse Oximetry
- Non-invasive: Measures oxygen saturation painlessly, without requiring a blood sample.
- Instant Results: Provides immediate readings of oxygen saturation levels.
- Cost-effective: A simple, low-cost device suitable for inclusion in first aid kits.
Using Pulse Oximeters
Pulse oximeters typically measure oxygen saturation at the fingertip, earlobe, or toe:
- Procedure: Insert the finger into the device and ensure a secure fit for accurate readings.
- Reading Stability: Allow the device time to stabilize before recording oxygen saturation (SpO2) and pulse rate.
Interpreting Readings
Understanding SpO2 levels:
- Normal Range: Typically between 95% and 100% in healthy individuals.
- Mild Hypoxia: SpO2 levels of 91% to 94%, indicating potential health concerns.
- Significant Hypoxia: SpO2 below 90%, requiring immediate medical attention due to inadequate oxygen delivery to tissues.
Factors Affecting Accuracy
Several factors can influence pulse oximeter accuracy:
- Circulation Issues: Poor circulation or cold fingers may affect readings.
- External Factors: Nail polish, artificial nails, ambient light, and motion can interfere with readings.
- Carbon Monoxide: In cases of poisoning, pulse oximeters may not detect carbon monoxide-bound haemoglobin accurately.
Limitations of Pulse Oximetry
While useful for indicating oxygen saturation levels, pulse oximetry does not measure total oxygen content in blood or assess oxygen delivery efficiency to tissues.
Clinical Considerations
For clinical decisions, abnormal pulse oximetry results should be verified with arterial blood gases or other appropriate tests.