What is blood oxygen saturation?

Oxygen saturation is the fraction of oxygen-saturated hemoglobin relative to total hemoglobin in the blood. Sometimes referred to as O2 sats, or simply, sats and refers to the extent to which hemoglobin is saturated with oxygen. The human body requires and regulates a very precise and specific balance of oxygen in the blood.

Normal oxygen saturation is usually between 94% and 98%. levels below 87-88 normally are alarmingly low and it is an indication of a respiratory or blood circulation complication. In this case, medical practitioners will instruct further tests and might possibly recommend an oxygen inhaler in the form of CPAP machines.

A severe lack of oxygen in the body might lead to a condition called hypoxia-and-hypoxemia . Which is quite dangerous as it could lead to fainting or damage to the brain, liver, and other organs.

How is blood oxygen level measured?

Measurement of the amount of oxygen (O2) in the blood is vital for the prediction of a patient’s tissue oxygen status. The most efficient way to monitor blood oxygen levels is by an arterial blood gas or ABG test. An arterial blood gas (ABG) test measures the amounts of arterial gases, such as oxygen and carbon dioxide. An ABG test requires that a small volume of blood be drawn from the radial artery with a syringe and a thin needle, but sometimes the femoral artery in the groin or another site is used. This procedure is very accurate, but it can be a little painful.

Blood oxygenation is most commonly assessed non-invasively by pulse oximetry. Although the pulse-oximeter  test is easier, quicker, and not painful, it is not as accurate as the ABG test. It is convenient but it has limitations. Results can be influenced by factors such as dirty fingers, bright lights, nail polish, and poor circulation in the tested tissues.

The body closely monitors blood oxygen levels to keep them within a specific range, so that there is enough oxygen for the needs of every cell in the body. Human cells use nutrients from food and oxygen to create adenosine triphosphate (ATP), the energy source that fuels cell function. If your cells receive too little oxygen, they produce less energy. If your cells need more energy, they use more oxygen. That’s why your breathing rate increases when you exercise. A person’s blood oxygen level is an indicator of how well the body distributes oxygen from the lungs to the cells, and it can be important for people’s health.


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