Oxygen is the source of life on Earth. Every cell in our body needs it at every moment of time. Its deficiency leads to serious health consequences: disruption of brain function, problems with memory and speech, and diseases of internal organs. In severe cases, oxygen deprivation leads to death. Pulse oximetry helps determine oxygen saturation levels. This technique uses devices called pulse oximeters, which quickly and accurately indicate the amount of this element in arterial blood. Such equipment makes it possible to prevent the development of hypoxia in time, improve the patient’s condition, and sometimes save his life.
What it is
The amount of oxygen in the blood fluid directly affects a person’s ability to work, well-being, and health status. To determine and study this indicator, pulse oximetry is used.
With a deficiency of this substance, human vital activity decreases. Often occurs against the background of cardiovascular diseases. If the numbers are within normal limits, you feel satisfied.
For the examination you will need a pulse oximeter. It is a sensor that is attached to the patient’s finger or earlobe. This sensor is connected to the monitor.
Each heartbeat is accompanied by a sound signal. Modern meters have the ability to monitor heartbeats.
Answers to questions
Does it matter which finger is used?
Most health care workers place the device on the index finger, although research has found that reliable readings are recorded on the middle finger of the dominant hand. The index finger is also close in meaning.
According to the instructions, long or false nails make it difficult to insert your finger into the clamp correctly, and dark nail polish (black or blue) can affect the accuracy of oximetry.
False data may also be recorded if there is a circulatory disorder with poor blood flow to the extremities, Raynaud's syndrome or cold fingers.
Do patients need a pulse oximeter?
The device will not be superfluous, but you should not completely trust only oxygenation indicators. It is important not to ignore symptoms such as shortness of breath or persistent cough even with normal SpO2 values.
In the hands of nervous patients, the device causes confusion without evidentiary value: even if the device shows a slight drop in values, they call their doctor. It is important to understand that a pulse oximeter is a diagnostic “add-on”, and not the only criterion for assessing a person’s condition.
Kinds
Doctors distinguish 2 types of research.
- Transmission. It is based on determining the light current that passes through the tissues of the body. The sensor is attached to different parts of the body to fully ensure the passage of the light flux.
- Reflection. Determines the display of light flux from tissues. This type of examination allows you to find out about the ratio of hemoglobin and oxygen.
The device sensor has 2 LEDs - a source of red and infrared light. They turn on one by one. The photodetector is designed to determine the flow of light after it is absorbed by tissue.
Operating principle of the device
Knowing what a pulse oximeter is and taking into account the basic principle of operation of this device, you can choose the required device for yourself that will fully meet all your needs. At first glance, such a small device has a rather complex operating principle. It consists of several main parts, namely:
- sensor with LEDs;
- microprocessor;
- display.
The sensors are configured in a specific way so that when the device is turned on, they emit light that passes through the tissue and is absorbed by the internal organs.
The degree of radiation absorption directly depends on the level of oxygen saturation of hemoglobin contained in the blood. The received data is processed by a microprocessor and appears on the display in the form of digital values or in the form of graphs. The device remembers previous values, which makes it possible to study the medical history.
Rules
The meter is not difficult to use. When working with the device, it is important to follow certain rules.
- Before using the pulse oximeter, check the battery charge.
- After turning on, you should wait a few seconds for the self-test to complete.
- The sensor is attached to the finger. The fixation should be strong, but not exert strong pressure.
- Wait 20 seconds for the device to display numbers on the monitor.
- If the numbers are in doubt, the study should be repeated several times.
Erroneous indicators are rare. Since the device is electronic, it can show numbers that would be physiologically impossible.
The fingernail should not be coated with varnish or other substances. This affects the distortion of the final indicators.
The pulse oximeter has increased sensitivity to external light and movements. During the measurement process, the patient is at rest and does not move. Even a small tremor can create a pulse curve and distort saturation readings.
Most of the devices are new and easy to use. Does not require specific preparation of the patient before the examination.
Instructions for use
The pulse oximeter is easy to use at home; it is a simple and intuitive device. Its main advantage is that to obtain data it is not necessary to take blood from the patient; for example, previously this could only be done in a laboratory setting. Modern measuring instruments do not require invasive interventions, which makes them more accessible. They are disposable or reusable, the latter being especially relevant for those patients undergoing oxygen therapy. So, a person independently monitors O2 levels, and in case of poor results can consult a doctor.
Portable devices run on a pair of AA batteries, some are charged from the mains. You can measure the saturation index and heart rate with the help of loved ones or on your own; the device is also used for people in a serious and unconscious state. Important rules of use:
- Before use, you need to look at the charge level, which is reflected on the monitor. If the charge is too low, the data may be corrupted. It is also better to wipe the sensor from dust with a dry cloth.
- Once the device is turned on, it will boot. You can put on the sensor after 1-2 minutes. Avoid sources of bright light and electromagnetic radiation as this will affect the results.
- An important condition for correct data is immobility during the process. This does not apply to neonatal sensors. The pulse oximeter is attached to the ear (a clothespin-shaped sensor), nose or finger. For finger nails, it is imperative that the nail and finger are clean, without varnish, as this affects the result.
- After connecting the device, you need to wait up to 25 seconds; during this time it is better not to move.
- The monitor displays heartbeat and blood O2 levels.
After this, you should not leave the device turned on, you need to turn it off, fold it and put it away from direct sunlight and moisture. We looked at a classic example of using the device; in addition, there is technology for measuring saturation in sleep.
Indications
The main indications for the study in the presence of cardiovascular diseases:
- arterial hypertension of the 2nd degree, which manifests itself in the morning and evening;
- heart failure;
- pulmonary heart;
- Pickwick's syndrome.
The pulse oximeter is attached to the finger, and the patient is at rest.
Features of the device
The pulse oximeter passes light waves of different lengths through the tip of your finger (this is painless). The waves are “targeted” at hemoglobin, a protein molecule in the blood that carries oxygen through the vascular bed.
The device functions better on warm hands than on cold hands. And because oxygen levels can fluctuate, measurements need to be taken several times throughout the day. Measurements should also be taken in various conditions, for example, lying on your back or after walking.
How is it carried out?
The device is equipped with a light source, which is located in the sensor of the device. Capable of generating different waves. This light is partially absorbed by hemoglobin. The stage of absorption depends on how saturated it is with oxygen and whether it can be restored.
When the degree of wave absorption is determined, the device will calculate the amount of oxyhemoglobin. The performance of the processor depends on the pulse in the bloodstream.
The image may show curved lines that indicate the intensity of the heartbeat. If blood flow is slow, the pulse oximeter may show false numbers.
A computer located inside detects the pulsation. After this, a curve of arterial blood flow appears on the monitor.
Efficiency at home
If a person has mild COVID-19 and is isolating at home, an oximeter can be a useful tool to check their oxygen levels. This will help identify a decrease in oxygen (hypoxemia) at an early stage.
Theoretically, people from several risk groups are susceptible to problems with oxygen:
- Patients with chronic lung diseases (chronic bronchitis, asthma, COPD).
- Active smokers.
- Persons with cardiac pathology.
- Overweight people.
In addition, with an asymptomatic form of the disease, a person can independently determine the problem with oxygen saturation in the body. The goal of this approach is to identify violations at an early stage.
A pulse oximeter for coronavirus that shows 100% SpO2 has no advantage over 96% SpO2. Clinically significant is a persistent decrease in saturation of less than 95%.
Norms and deviations
In a healthy state, the numbers should be between 95-98%. For people over 70 years old – 94-97%. During oxygen therapy it can reach 100%. Figures less than 90% indicate a pathological process.
You can get normal, reliable results in the absence of such influence:
- trembling in hands;
- shaking, movements;
- bright light;
- severe anemia;
- vascular spasms;
- arrhythmia;
- tremor.
These factors provoke a restless state. Therefore, the results end up being erroneous.
Modern meters allow you to accurately estimate the level of oxygen in the blood. But no electronic device can provide absolute accuracy. Permissible deviations are 2-3%, 1 beat per minute for pulse rate.
Portable devices are worn on the finger and provide objective information. With pulse oximetry, there is no need to conduct additional studies.
In children
During the research process, the age of the subject is very important. There is a difference between the norms of oxygen content in the bloodstream, heartbeat, and between adults and children.
The body of newborn babies contains very little iron, and the lungs are not developed. For this reason, the data may be in the range of 92-95%. These results do not indicate the presence of a specific disease. In premature babies, saturation can be 82%.
In such cases, artificial ventilation of the lungs is connected, which compensates for the lack of oxygen in the body. A pulse oximeter for newborns can be used in the first days of life. The pulse at this age reaches 135 beats. It decreases with age. From the age of 15, the normal heart rate is 75-80 beats per minute.
In adults
Pulse oximetry allows you to identify the degree of oxygen deficiency in adults:
- norm – 95% or more;
- 1st degree – 90-94%;
- 2 – 75-89%;
- 3 – data less than 75%;
- hypoxemic coma – less than 60%.
If deviations develop, you will need to consult a doctor, as this can be dangerous to health. The treatment method depends on the degree of deficiency.
The norm of oxygen in the blood is saturation, in an adult it is 97-99%. Anything below 95% is a deviation.
Measuring in a dream
Night pulse oximetry is needed when breathing stops or becomes difficult at night. This picture is often found in diseases of the thyroid gland, obesity, hypertension, pathology of the lungs and heart. Against the background of such problems, a person suffers from sleep disordered breathing, which causes weakness, confusion, drowsiness, bad mood, and dizziness in the morning. The danger lies in the fact that death can occur in such patients during sleep.
Based on the symptoms described, the doctor suspects a lack of oxygen supply during sleep, and monitoring is needed to confirm suspicions.
Checking the degree of O2 saturation at night is done using wrist devices; they are used in a hospital or at home. This device consists of a finger sensor and a wrist strap; the patient puts it on before going to bed. There is no need to turn on the device, it turns on itself - 30,000 times a night. Typically, the inspection period lasts from 10 pm to 8 am.
There are also rules here:
- the patient should sleep in comfortable conditions, the room temperature is 20-23 degrees;
- It is forbidden to overeat, drink tea and coffee before going to bed;
- do not take sleeping pills;
- before starting the screening, you need to place a diary in front of your bed;
- the diary records all the moments when the patient woke up: time, painful sensations;
- In the morning the sensor is removed, the time of rise and sensations are recorded in the diary.
The pulse oximeter and diary are given to the attending doctor. For accurate conclusions, you will need to undergo additional examination: ultrasound, tests, examination by a cardiologist or other specialists. Based on these studies, a diagnosis is determined and treatment is prescribed.
Pulse oximeter: main characteristics
The Armed pulse oximeter, designed for single measurements, is in great demand. This device is widely used in hospital settings, as well as at home to monitor patients suffering from chronic pathologies of the cardiovascular system and respiratory system. Pulse oximeter YX 300 "Armed" is used in fitness centers to control physical activity, since at this time muscles burn oxygen.
This device is characterized by a bright design, ease of operation, light weight and dimensions.
In what cases is a pulse oximeter used?
This is a device that allows you to determine the oxygen saturation of your blood. The functioning of the body as a whole depends on the results obtained. But most often, a pulse oximeter with a sensor for children and newborns is worth purchasing if there are problems in the functioning of the respiratory system, the hematopoietic system, problems with the heart rhythm, and also:
- Heart disease;
- Pneumosclerosis;
- Emphysema;
- Apnea;
- Pickwick's syndrome;
- Bronchial asthma;
- Cystic fibrosis.
However, despite the fact that today almost every family has such important devices for diagnosing a person’s health as blood pressure monitors and glucometers, not everyone has a pulse oximeter. However, this new product is capable of protecting the entire family, and above all, its small members themselves, starting from the first days after birth.
What are the benefits of portable instruments used to monitor SPO2?
If you need to take multiple measurements, it is best to purchase a portable oximeter for children. He will take your pulse and perform an oxygen test. The advantages of these compact devices are obvious:
- Convenient, compact sizes. The device can be carried in a case in a bag, which allows you to keep it always at hand;
- Measurement indicators are always as accurate as possible;
- The measurement result is displayed after a few seconds;
- Very easy to use.
It’s easy to buy a children’s medical pulse oximeter even for a newborn – the store’s website has devices and sensors suitable for babies. They are represented by different models of medical equipment, which are offered by the Chinese company ChoicemMed and the American company Nonin. You can choose devices depending on your budget with delivery to any city in the Russian Federation.
What to look for when buying an oximeter?
- Find out how quickly the device is ready for use after switching on;
- Check the accuracy of the readings;
- Familiarize yourself with the shockproof characteristics, because this is primarily a device designed for children;
- The design of the device is important. This could be a clothespin, a cover;
- Make sure the display is bright enough and easy on the eyes. Does the image quality change when changing the sensor angle? In addition, modern models, for example, the MD300C5, have 10 screen brightness levels;
- For constant monitoring, choose devices with a memory function for up to a day. After the scammers, the data can be transferred to a computer and graphs of well-being can be built;
- It will be better if you buy a pulse oximeter that is manufactured according to the European CE directive.
Five reasons for incorrect operation
The correct interpretation of sensor information depends on five factors. The result can be distorted by:
- pigment spots on the skin, varnish, acrylic, gel on nails;
- bright artificial or natural lighting;
- trembling, movements;
- poor perfusion, blood supply to a specific part of the body;
- intoxication caused by carbon monoxide.
The nail coating is capable of absorbing light from the device. In some cases, this interferes with the determination of oxygenated hemoglobin. It is possible to fix the sensor on the side surface of the finger. Pigment on the skin can also distort the results. The paint blocks the signal. The oximeter does not function fully.
Instead of wearing your fingers, attach the device to your toe or earlobe. An error is indicated by an inconsistent pulse waveform. How to check a pulse oximeter? Place it on your own finger. The pulse line should be clear. You can perform a test on several patients at once, compare the results and draw a conclusion. Inaccurate information is determined in case of carbon monoxide poisoning (after fires).
When the saturation is below 94%, you need to doubt the correct operation of the oximeter. Reposition the device. Take the measurement several times. Follow the pulse wave. If the problem persists, turn off the sensor and turn it on again. How to check the operation of a pulse oximeter is now known.
