Blood Oxygen Monitor Finger Pulse Oximeter

What is blood oxygen and why is it important to measure?

Oxygen saturation, sometimes referred to as O2 ‘sats’, refers to the extent to which haemoglobin is saturated with oxygen. Haemoglobin is an element in your blood that binds with oxygen to carry it through the bloodstream to the organs, tissues, and cells of your body.

Normal oxygen saturation is usually between 96% and 98%. Any level below this (referred to as desaturation, or hypoxemia) is considered dangerous and warrants urgent oxygen supplementation and/or treatment for your lung condition. A drop in O2 sats is referred to as desaturation, or hypoxemia.

Conditions Affecting Blood Oxygen Levels

Blood disorders, circulatory problems, and lung issues may negatively affect your blood oxygen saturation level, as they may prevent you from adequately absorbing or transporting oxygen.

Examples of conditions that can affect your O2 sat level include:

Chronic obstructive pulmonary disease (COPD), including emphysema and chronic bronchitis

Asthma

Collapsed lung (pneumothorax)

Anaemia

Heart disease

Pulmonary embolism

Congenital heart defects

Measuring Your Levels

Oxygen saturation is most commonly measured by two metrics:

Arterial blood gases: The value obtained from arterial blood gases or ABGs (SaO2) describes the oxygen saturation of arterial blood. It is obtained by drawing blood from an artery such as the radial artery in the wrist or the femoral artery in the groin. ABGs are measured in millimetres of mercury (mmHg) and can be a clue as to how efficiently your body is exchanging oxygen and carbon dioxide.

Pulse oximetry: The value obtained from peripheral capillary blood using pulse oximetry (SpO2) often closely reflects the levels that would be found in arterial blood.

Pulse oximetry has the advantage of being a non-invasive test; it uses a probe attached to a finger or earlobe or other regions of the body that reads the wavelengths of light reflected from the blood. Not only are pulse oximeters standard for monitoring people in the hospital, but today's wearable technology empowers people to track their own saturation levels.