When using a pulse oximeter at home, it is important that you understand what the readings mean.
What exactly is the impact of safe, normal & low blood oxygen levels, and how should you respond?
Essentially, blood oxygen levels are important as they provide information on how blood cells are transporting oxygen around the body.
Each cell can carry up to four oxygen molecules, and you clearly need a good supply to keep vital organs such as the heart and brain working at optimum levels.
In short, vital systems need a normal percentage of oxygen inside your blood at all times.
This is known as oxygen saturation, and you use a pulse oximeter to measure this.
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Blood Oxygen Saturation Levels
Pulse Oximeter Readings
Oxygen levels are measured in relation to the percentage of oxygen saturated in your blood. In medical terms, this is your SpO2 level.
Normal Blood Oxygen Levels
The normal blood oxygen saturation rate is between 95% and 100%.
‘Concerning’ Blood Oxygen Levels
If oxygen concentrations fall between 91% and 95%, it is a cause for concern. This signifies an underlying medical problem and it is advised that if you have a reading in this range, that you contact your healthcare provider.
Low Blood Oxygen Levels
Low blood oxygen rate is medically defined as percentages that fall below 90% oxygen saturation. In short, readings at this level indicate a medical emergency. You should call 911 immediately if blood oxygen saturation falls this low
Below 85% Oxygen Saturation Levels
If a patient’s oxygen saturation level falls to 85% or below, the brain is being adversely affected due to lack of oxygen. Symptoms include vision changes or loss of vision and total blackout.
If blood oxygen saturation levels fall to around 67%, Cyanosis will set it.
The lack of oxygen being transported by your blood cells, causes a blue tinge to develop on your skin. Your mouth, lips, and beneath your fingernail matrix will be affected first, followed by the spread occurring over the rest of your body.
Understanding blood oxygen saturation levels is very important when using a pulse oximeter at home. If you take a reading lower than 95% you now know that action does need to be taken.
- “Regulation of Tissue Oxygenation”, Pittman RN. San Rafael (CA): Morgan & Claypool Life Sciences; 2011.
- “Central and Peripheral Cyanosis”, Parul Pahal; Amandeep Goyal, Treasure Island (FL): StatPearls Publishing; 2021.
- “Davies, H.J.; Williams, I.; Peters, N.S.; Mandic, D.P. In-Ear SpO2: A Tool for Wearable, Unobtrusive Monitoring of Core Blood Oxygen Saturation. Sensors 2020, 20, 4879. https://doi.org/10.3390/s20174879