Oximeter Buyer's Guide
The main measurement indicators of the oximeter are pulse rate, blood oxygen saturation, and perfusion index (PI). Blood oxygen saturation (SpO2 for short) is one of the important basic data in clinical medicine. Oxygen saturation refers to the percentage of bound O2 volume in the total blood volume of the total bound O2 volume.
Management categories of oximeters
Management category of oximeter: Class II medical device
Oximeter measurement indicators
The main measurement indicators of the oximeter are pulse rate, blood oxygen saturation, and perfusion index (PI).
Pulse rate: Pulse is the pulsation of the superficial arteries. A normal person's pulse and heartbeat are the same.
Heart rate is the frequency at which the heart beats. The average person is between 60-90 beats per minute. However, when people exercise and are nervous, their heart rate will increase.
Pulse rate is the number of pulses per minute.
Normally the pulse rate and heart rate are the same. The pulse rate is lower than the heart rate during atrial fibrillation or frequent premature contractions.
Blood oxygen saturation: Blood oxygen saturation (oxygen saturation abbreviated as SO2) is one of the important basic data in clinical medicine.
The oxygen consumed by the human body mainly comes from hemoglobin (there are four types of hemoglobin in normal blood: oxyhemoglobin (HbO2), reduced hemoglobin (Hb), carboxyhemoglobin (CoHb), and methemoglobin (MetHb).
Among them, reduced hemoglobin is reversibly combined with oxygen, and carboxyhemoglobin and methemoglobin are not combined with oxygen. ) carried by the oxygen. Usually, the oxygen content in the blood refers to the amount of oxyhemoglobin in the blood. The physical quantity of blood oxygen saturation is used to describe the change of the oxygen content in the blood.
Oxygen saturation refers to the percentage of bound O2 volume in the total blood volume of the total bound O2 volume.
The oxygen saturation of normal human arterial blood is 98% and that of venous blood is 75%.
It is an important indicator to reflect the oxygen status in the body. It is generally believed that the normal value of blood oxygen saturation should not be lower than 94%, and below 94% is regarded as insufficient oxygen supply.
Perfusion Index (PI): Usually PI is used as a parameter index, which can reflect the limb perfusion status of the tested person, indicating the detection accuracy of the machine. That is, it can still be detected under the conditions of low perfusion and weak perfusion.
Moreover, through the display of PI, it can also indicate the problem of the subject's own limb condition, that is, when low perfusion occurs, it indicates whether the subject has its own causes, such as heart problems, shock, etc., and can also reflect Whether there are external factors such as cold weather, poor peripheral circulation, etc., so as to judge by the above conditions!
PI refers to the perfusion index (Perfusion Index, PI), and the PI value reflects the pulsatile blood flow, that is, the blood perfusion ability. The greater the pulsatile blood flow, the greater the pulsatile component and the greater the PI value.
Therefore, both the measurement site (skin, nails, bones, etc.) and the patient's own blood perfusion (arterial blood flow) will affect the PI value. Since sympathetic nerves affect heart rate and arterial blood pressure (affecting pulsatile arterial blood flow), the body's neuromodulation system or mental state also indirectly affects PI values. Therefore, under different anesthesia states, the PI value will also be different.
Introduction of finger clip oximeter
By sequentially driving a red LED (660nm) and an infrared LED (910nm).
The blue line represents the induction curve of the receiving tube to reduced hemoglobin when hemoglobin does not carry oxygen molecules. From the graph, it can be seen that the reduced hemoglobin absorbs 660nm red light relatively strongly, while the absorption length for 910nm infrared light is relatively weak.
The red line represents the induction curve of the receiving tube to oxyhemoglobin when hemoglobin and red blood cells with oxygen molecules are present. It can be seen from the figure that the absorption of red light at 660 nm is relatively weak, and the absorption of infrared light at 910 nm is relatively strong.
In blood oxygen measurement, the difference between reduced hemoglobin and oxygenated hemoglobin by detecting the difference between the two types of light absorption at different wavelengths is the most basic data for measuring blood oxygen saturation.
In the blood oxygen test, 660nm and 910nm are the two most common wavelengths. In fact, to achieve higher accuracy, in addition to two wavelengths, even up to 8 wavelengths, the main reason is that human hemoglobin is not only reduced to hemoglobin. In addition to oxyhemoglobin, there are other hemoglobins, we often see carboxyhemoglobin, and more wavelengths will help you to do better precision.
Applicable people for oximeter
1. People with vascular disease (coronary heart disease, hypertension, hyperlipidemia, cerebral thrombosis)
2. People with respiratory diseases (asthma, bronchitis, chronic bronchitis, pulmonary heart disease, chronic obstructive pulmonary disease...)
3. Seniors over 60 years old
4. People who work more than 12 hours a day
5. Blood oxygen monitoring in extreme sports and alpine hypoxia environment
6. Long-term alcoholics
