Pulse oximetry is a simple and inexpensive procedure that is used to measure the level of oxygen (or oxygen concentration) in the blood without the need to insert any instrument into the body. The oxygen concentration level should always be above 95 percent. However, oxygen concentrations may be lower if you have congenital heart or respiratory disease. The percentage of oxygen concentration can be measured using a pulse oximeter (a device that measures oxygen levels in the blood), which is a clamp-shaped sensor that is placed on a thin part of the body, such as the earlobe or nose.
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Part 1 of 2: Getting Started Using the Pulse Oximeter
Step 1. Understand the relationship between oxygen and blood
Oxygen is exhaled into the lungs, then circulated into the blood. The majority of oxygen attaches to hemoglobin. Hemoglobin is a protein located inside red blood cells (erythrocytes), which distributes oxygen throughout the body and tissues through the bloodstream. This is how our bodies get the oxygen and nutrients they need to function.
Step 2. Understand why this procedure was performed
Pulse oximetry is used to calculate the oxygen concentration in the blood for a variety of reasons. Pulse oximetry is commonly performed in surgery and other procedures that involve the administration of sedation (eg bronchoscopy), and for administration of supplemental oxygen. Pulse oximeters can also be used to assess the effectiveness of pulmonary drug performance, whether or not supplemental oxygen is administered, and to determine the patient's resistance to increased activity levels.
Your doctor may also recommend a pulse oximetry procedure if you are on a ventilator to support breathing, have sleep apnea, or have a serious medical condition such as heart disease; congestive heart failure; chronic obstructive pulmonary disease (COPD); anemia; lung cancer; asthma; or pneumonia
Step 3. Understand how the pulse oximeter works
Oximeter uses the properties of hemoglobin which is able to absorb light and the natural pulse of blood flow in the arteries to measure oxygen levels in the body.
- A device called a probe has a light source, a light detector, and a microprocessor that can compare and calculate the difference between oxygen-rich and oxygen-deficient hemoglobin.
- One side of the probe contains a light source of two different types: red and infrared. Both types of light are propagated through the body's tissues to a light detector located on the other side of the probe. Hemoglobin that is richer in oxygen absorbs more infrared light, whereas that which lacks oxygen absorbs red light.
- The microprocessor on the probe calculates the difference in oxygen levels and converts that information into a digital value. This value is then estimated to determine the amount of oxygen carried by the blood.
- Measurements of relative light absorption are made several times per second. Those measurements are then processed by the machine to provide a new picture every 0.5-1 second. The picture for the last 3 seconds is the average value that will come out.
Step 4. Know the risks of the pulse oximetry procedure
The risks associated with pulse oximetry are generally very small.
- If you use the oximeter for a long time, you may experience tissue damage at the probe site (eg fingers and ear). Skin irritation may occasionally occur when using probes containing adhesives.
- There may be other risks depending on the health and all specific conditions the user is experiencing. Consult your doctor if you have any concerns before starting the procedure.
Step 5. Choose a pulse oximeter according to your needs
There are several different types of pulse oximeters on the market. The most popular types are fingertip pulse oximeters and handheld portables.
- Portable pulse oximeters can be purchased at a variety of stores, including pharmacies: for example Century and D' Batas Kota; major retail stores: eg Hypermart; and even sold on the internet.
- Pulse oximeters are generally clamp-shaped and look like clothespins. There is also an adhesive probe that can be attached to a finger or forehead.
- The use of probes for children and toddlers must be of the appropriate size.
Step 6. Make sure the oximeter is charged first
Connect the oximeter to a wall or floor outlet, if it is not a portable type. If the oximeter is portable, make sure the battery is sufficiently charged by turning it on before use.
Part 2 of 2: Using a Pulse Oximeter
Step 1. Determine whether you need a one-time measurement or continuous observation
The probe will be removed after measurement, except for continuous observation.
Step 2. Remove anything that absorbs light from the oximeter
For example, if you plan to use the oximeter on your finger, it is very important to remove anything that absorbs light (such as dried blood or nail polish) to avoid erroneous low readings.
Step 3. Warm the area where the probe will be attached
Cold temperatures can cause blood flow is not smooth, which will lead to measurement errors by the oximeter. Make sure the temperature of your finger, ear, or forehead is at room temperature or slightly warmer before starting the procedure.
Step 4. Remove any sources of distraction from the surrounding environment
Ambient light that is too bright, such as ceiling lights, phototherapy (therapy using high-intensity light), and infrared heating can blind the oximeter's light sensor and give inaccurate calculations. Solve the problem by reusing or covering the sensor with a towel or blanket.
Step 5. Wash both hands
This method will reduce the transmission of microorganisms and body secretions.
Step 6. Glue the probe
The probe is usually attached to the finger. Turn on the oximeter.
- The probe can also be attached to the earlobe and forehead, although research suggests that the earlobe is not reliable in measuring oxygen concentration.
- When using a finger probe, the hand should always be placed on the chest, above the heart, rather than dangling in the air (as most patients do). This method can help minimize any movement.
- Minimize movement. The main cause of inaccurate oximeter calculations is excessive movement. One way to make sure movement doesn't affect the count is to compare the heart rate shown on the monitor to that measured manually. Both heart rates should be within 5 beats/minute of each other.
Step 7. Read the measurement results
Oxygen concentration and heart rate are displayed in seconds on the illuminated display screen. A number that ranges from 95% to 100% is considered normal. If the oxygen level drops below 85%, seek medical attention immediately.
Step 8. Keep a record of the measurement results
Print the measurement results, and/or download them to a computer if the oximeter has this feature possible.
Step 9. Troubleshoot if the oximeter makes an error
If you believe the oximeter is giving inaccurate results, try the following steps:
- Make sure there is no interference of any kind (either from the environment or where the probe is attached).
- Warm and rub the skin.
- Use a warming vasodilator that can help open the blood vessels (eg Vicks Vaporub balm).
- Use another probe attachment.
- Use a different probe and/or oximeter.
- Consult a doctor if you are still not sure that the oximeter is working properly.
Tips
Don't worry if the oxygen level doesn't reach 100%. Very few people have oxygen levels up to 100%
Warning
- Do not use the pulse oximeter sensor on a finger whose arm has an automatic blood pressure gauge. Blood flow to the finger will stop when the tire is inflated.
- The use of pulse oximetry in smokers is futile. Oximetry cannot distinguish between normal oxygen concentrations and the concentration of carbon monoxide in hemoglobin that occurs as a result of inhaling smoke.
