A pulse oximeter is a valuable tool, but it has limitations.
Anything that may hinder circulation to the limb or location where the pulse oximetry sensor is located. Anything that spoils the circulation will give incorrect readings or no readings.
It is an infrared LED that pierces the skin, looking for specific pulsation changes in the transmission of blood through the meat.
I will add the temperature as most of the time the sensor is on a limb, ear, finger, foreskin.
Another common finding, the most common among western women, is nail polish, you won’t get anything, as the nails have a coat of paint.
What factors can affect pulse oximetry reading?
By reducing the incidence of unrecognized hypoxia, pulse oximetry has greatly reduced in-hospital mortality.
The principle of pulse oximetry is based on the differences between oxygenated and deoxygenated red blood cells in the absorption of wavelengths of red and infrared light.
The pulse oximeter detects minute color changes in pulsating blood and calculates how many oxygen molecules are bound to hemoglobin or oxygen saturation. A strong and regular pulse is important for a good signal and an accurate reading.
Unfortunately, many critically ill patients do not have good pulses anywhere, resulting in inaccurate or fluctuating readings.
Causes of false high or low spo2 readings
Causes of incorrect readings on pulse oximetry
- Falsely low
- Hypoperfusion
- Vasoconstriction
- Calloused skin
- Excessive movement
- Incorrect sensor application
- Methemoglobinemia
- Falsely high
- Carbon monoxide poisoning
- Methemoglobinemia
Moving and dislodging of the sensor, which may be caused by a rhythmic movement such as the tremors of Parkinsonism, seizures, or even shivering, may lead to inaccurate readings.
Insufficient blood flow, cold, nerve blocker medications and fear, fake Fingernails, Interference of Light.
Pulse Oximeters: Answering Your Frequently Asked Questions
False low Pulse Oximetry Reading
Pulse oximetry generally provides an accurate noninvasive estimate of arterial hemoglobin saturation, but various confounders can lead to errors.
What are the 2 readings on a pulse oximeter?
A finger pulse oximeter measures two things:
-Blood Oxygen Saturation
-Pulse Rate
Pulse Oximeters
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