The main parameters measured by a pulse oximeter are blood oxygen saturation, pulse rate, and perfusion index (PI).
Blood oxygen saturation is a parameter that reflects the proportion of oxygenated hemoglobin in the blood.
The oxygen consumed by the human body mainly comes from hemoglobin. There are four types of hemoglobin in normal blood: oxygenated hemoglobin (HbO2), reduced hemoglobin (Hb), carboxyhemoglobin (CoHb), and methemoglobin (MetHb). Among them, reduced hemoglobin is reversibly bound to oxygen, while carboxyhemoglobin and methemoglobin do not bind to oxygen.
The effective oxygen molecules in blood form oxygenated hemoglobin (HbO2) by binding with reduced hemoglobin (Hb). Blood oxygen saturation is an important parameter to measure the oxygen-carrying capacity of blood in the human body. By measuring blood oxygen saturation, the oxygen content of patients can be promptly understood, and it has extremely important clinical value. The normal blood oxygen saturation of arterial blood in a healthy person is 98%, and venous blood is 75%. It is an important indicator reflecting the oxygen status of the body, and a normal value of blood oxygen saturation is generally considered to be no lower than 94%. Below 94% is considered as inadequate oxygen supply.
Factors affecting the accuracy of blood oxygen saturation measurement:
(1) Incorrect placement may result in incorrect results. For example, for fingertip pulse oximeter, if it is clipped on the earlobe, it may result in inaccurate measurement.
(2) Factors such as pulsation during measurement, when pulsation decreases to a certain limit, measurement cannot be performed. For example, in cases of shock, hypothermia, or use of vasoactive drugs.
(3) Light interference can affect measurement accuracy. Strong light will affect the transmission of light through the skin tissue, and nail polish or shiny nails can also affect measurement accuracy.
(4) Human movement may also interfere with measurement accuracy, as it has the same frequency range as pulsation. Therefore, it is recommended to measure blood oxygen saturation in a quiet state of the body.
Pulse refers to the pulsation of superficial arteries, which is consistent with heartbeat in normal individuals. Heart rate is the frequency of heartbeats. Generally, the heart rate of a normal person falls between 60-90 beats per minute. However, heart rate may increase during exercise or stress. Pulse rate refers to the number of pulses per minute. The TeleRPM Pulse Oximeter (BLE) 2022 is an important and commonly used device for monitoring blood oxygen saturation (SpO2) and pulse rate. It is a small, compact, simple, reliable, and durable physiological monitoring device.
Perfusion Index (PI) is a parameter that reflects the perfusion status of the limbs of the subject being tested, indicating the accuracy of the machine's detection. It can detect perfusion even under conditions of low perfusion and weak perfusion. The display of PI can indicate issues with the limb condition of the subject being tested. A low PI value may indicate underlying causes such as heart problems or shock, as well as external factors such as cold weather or poor peripheral circulation.