Pulse oximeter
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Oxygen – fuel for the human body
The human body needs approx. 400 litres of oxygen each day. Oxygen keeps the cells in your body alive and functioning. Transporting this vast quantity through our bloodstream requires the use of a “carrier”. The oxygen becomes attached to the haemoglobin contained in the red blood cells and is thus carried through the body via the bloodstream.
What is a pulse oximeter?
The
pulse oximeter is a measuring device for monitoring the pulse and oxygen
saturation. It enables you to measure arterial oxygen saturation – an important
vital sign in acute diseases. These measurements are therefore important for a
wide range of medical purposes, especially for people with certain health
problems, where monitoring their blood oxygen level and heart rate is critical.
Pulse oximeters are available in
different shapes and sizes. The most commonly used pulse oximeter is a small
device that is attached to your finger.
What is a pulse oximeter used for?
Pulse oximeters are used in various situations where it is necessary to monitor the oxygen level of the blood and the heart rate. Whilst emergency doctors give emergency medication based on a patient’s oxygen levels, at home, the pulse oximeter is used for care and monitoring. The monitoring provides support with chronic and acute respiratory diseases such as COPD and Covid-19. People with asthma, long Covid and sleep apnoea also use pulse oximeters for monitoring.
The pulse oximeter can also be used as an instrument to monitor the effect of medication or other treatments.
Another exciting use is sport at high altitudes. Many sportspeople, such as amateur pilots, mountaineers or skiers, use pulse oximeters to monitor their oxygen levels. In general, sportspeople can use the devices to keep an eye on their vital signs.
How does a pulse oximeter work?
For the measurement, the pulse oximeter uses two light beams with different wavelengths, which hit your finger when inserted into the housing. The light waves are then absorbed by the blood in the vessels. The amount of light absorbed depends on the amount of oxygen in the blood. When the light returns to the pulse oximeter, the device can calculate the amount of oxygen in the blood.
When blood moves through the finger during a heartbeat, the heart rate can also be measured using the light intensity. The pulse rate is calculated from the number of heartbeats per minute. A normal resting pulse in adults is between 60 and 80 beats per minute. If the pulse is higher or lower than this value, this may be a sign of illness.
How does a pulse oximeter measure the oxygen level in the blood and what value is in the normal range?
Pulse oximeters measure the oxygen level of the blood by measuring the amount of oxygen that the blood carries. The oxygen level of the blood is called oxygen saturation. The higher the oxygen level of the blood, the better.
- 97 – 100%: Ideal
- 90 – 96%: Normal
- < 90%: Action necessary (e.g. opening window, walking in the fresh air, ...)
- < 85%: Critical! Seek medical attention