Final answer:
A pulse oximeter may give false readings due to factors such as movement, improper sensor application, low perfusion, substances like carboxyhemoglobin or methemoglobin, nail polish or fake nails, external light sources, and skin pigmentation. Understanding these factors is crucial for accurate percent saturation measurements.
Step-by-step explanation:
Causes of False Readings in Pulse Oximeters
A pulse oximeter may provide false readings under certain conditions despite its crucial use for measuring percent saturation of oxygen in the blood. The normal range for pulse oximeter readings is 95-100%, and readings below this indicate hypoxemia or low blood oxygen levels. However, there are several factors that can lead to inaccurate measurements:
- Movement: If the person being measured is moving vigorously, the motion can disrupt the sensor's ability to accurately detect blood flow and oxygen saturation.
- Improper sensor application: The sensor must be properly attached to a part of the body with good circulation, usually the fingertip, to get an accurate reading.
- Low perfusion: If the blood flow to the extremity being measured is low, the sensor may not get an accurate reading of the oxygen saturation.
- High levels of carboxyhemoglobin or methemoglobin: These substances can affect the accuracy of readings because the pulse oximeter can mistake them for oxyhemoglobin.
- Nail polish or fake nails: These can block or alter the light pathways, consequently affecting the readings.
- External light sources: Bright lights or sunlight directly on the sensor can interfere with its operation.
- Skin pigmentation: Heavily pigmented skin can sometimes interfere with the light absorption, leading to false readings.
In clinical practice, it's essential to be aware of these potential inaccuracies to ensure that the percent saturation readings from a pulse oximeter are reliable.