Hello! I have been a doctor for 21 years. My name is Georgy Olegovich Sapego. In this article I will tell you about how pulse oximeters can lie, and what color the varnish should be on the nails.
Now everyone has a pulse oximeter and they lie all the time. In the last article we have already discussed home methods for detecting a lack of oxygen in the blood. Now let's talk about pulse oximeter errors.
Pulse oximeters measure the oxygen saturation of hemoglobin. Hemoglobin with oxygen and hemoglobin without oxygen absorb light differently. Pulse oximeters have two types of light that shine through the finger or other parts of the body. Then they cleverly calculate the oxygen saturation of hemoglobin.
Since pulse oximeters love to lie, it is advisable to be on your guard and instantly check suspicious indicators on a known healthy person. If the patient is doing badly, and the obviously healthy person's indicators are normal, then we can conclude that the patient is not pretending, and he is really bad.
Pulse
The pulse oximeter is called that because it needs a pulse.
Different people have fingers of different thicknesses and colors. It is not enough just to enlighten the finger. You need to understand that the light will pass through the blood.
If a person has a pulse in his finger, then the pulse oximeter understands that any changes in the thickness and color of the finger are associated with blood, and not with geomagnetic anomalies. If the pulse oximeter does not feel the pulse, then it is cut down with a clear conscience.
It's easy to check. Put your pulse oximeter on your finger, wait for the results, and then lift your finger up above your head and look at the readings. If the pulse oximeter goes out, then it is rustic. There is a chance that such a device will shut down even in a life-threatening situation.
There is also a verification option. You need to lean forward from a standing position and lower your finger with the pulse oximeter as low as possible to the floor. After the device shows readings, you need to cough at about the speed of your heart rate. If the pulse oximeter takes your cough kicks as a pulse and begins to sharply increase the result, then he is a fool. Such in a dangerous situation can fail.
From all this, the conclusions - do not shake a simple pulse oximeter, put your finger in it correctly, and in the case of use your child and small fingers to ensure that both light sources inside the pulse oximeter rest against finger. Otherwise, you will get a lie.
Do not put the pulse oximeter on the same hand as the cuff of the tonometer.
If your upper pressure drops below 90 millimeters of mercury, then the pulse oximeter will lie. At the same time, it can show both high and low values.
If a person is cold or chills, then the pulse oximeter on his arm may lie.
Diabetes
Remember glycated hemoglobin in diabetics? Many people check it. So if the glycated hemoglobin is higher than 7%, then the pulse oximeter will overestimate the values. And that's pretty mean. Because diabetics have more severe pneumonia and are more likely to get low oxygen levels in their blood.
Venous pulse
This is more likely to happen in a hospital, but theoretically you can do it at home. If the pulse oximeter sensor is tied tightly to the arm, then it can lie. Such adhesive sensors are common in the hospital, but with a fitness bracelet, probably a similar story. If you pinch the veins, they swell and pulsate slightly. The pulse oximeter takes them for arteries and counts saturation in them. Understated figures are obtained.
Ambient light
Sometimes the pulse oximeter is buggy and underestimates from bright light. Try turning off the lights in the room.
Nail polish
Black, green and blue lacquer underestimates the saturation values by 3, 5 and 6%, respectively.
Red varnish does not interfere.
If in doubt, it can be measured one-time by simply moving the sensor from the pad of the finger and nail to the lateral surfaces of the finger.
Have you played with a home pulse oximeter yet?
