What is a Pulse Oximeter?

Human beings depend on oxygen for life. All organs require oxygen for metabolism but the brain and heart are particularly sensitive to a lack of oxygen. A shortage of oxygen in the body is called hypoxia. A serious shortage of oxygen for a few minutes is fatal.

What is a Pulse Oximeter?
What is a Pulse Oximeter?

But, what is a pulse oximeter?

A pulse oximeter is a painless and reliable way for doctors to measure a person’s blood oxygen levels.

When you breathe, oxygen enters the lungs, passes through thin membranes, and enters the bloodstream, where it is then picked up by red blood cells and transported through the body to various organs.

A pulse oximeter is a tiny medical device that is usually slipped over the fingertip or attached to the earlobe and uses the refraction of infrared light to measure how well oxygen binds to red blood cells

Pulse oximeter readings chart

What are normal levels and when should I be concerned?

Normal SpO2 is usually at least 95%. Some patients with chronic lung disease or sleep apnea may have normal levels of around 90%.

A medical professional should be consulted to obtain a SpO2 reading below baseline or per facility protocol if the patient is a resident of a long-term care facility or has previously been evaluated by a physician.

Supplemental oxygen or other treatments might be needed.

How to check oxygen level at home?

  • Follow manufacturer instructions for cleaning and disinfecting pulse oximeters.
  • Be sure to disinfect the unit with an anti-viral wipe before and after use by each patient.
  • Turn the unit on with the power button (if it does not turn on, check the batteries).
  • Place the patient’s finger in the unit and wait for the number to display. In addition to SpO2, the unit might display heart rate and the waveform of the pulse.
  • This can be helpful because more distinct pulse waves indicate better measurement quality.
  • Some factors that can make it difficult for the unit to read are:
    • Dark-colored nail polish
    • Cold fingers or poor circulation
    • Tremor or movement
    • Too much pressure on the probe
    • Low blood pressure

Pulse oximeter readings normal range

What are normal readings, and when should I worry? Your pulse oximeter will show you your oxygen level as “SpO2.” 

Normal oxygen levels are at least 95%. Some patients with chronic lung disease or sleep apnea can have normal levels of around 90%. If your home SpO2 reading is less than 95%, call your health care provider.

is an oxygen level of 94 bad

A range of 94-99% is normal for healthy adults breathing room air which contains 21% oxygen.

Anyone who is not achieving the critical blood oxygen saturation level of 90% (SpO2) or of 55-60mmHg (SaO2), may require additional oxygen.

A qualified medical practitioner will assess your situation and prescribe the appropriate dose of supplemental oxygen.

Normal oxygen saturation

Oxygen saturation levels measure the degree to which the hemoglobin contained in the red blood cells has bonded with oxygen molecules.

Oxygen is taken in by the lungs when we breathe in. The two most common ways of assessing the saturation of oxygen in the blood are arterial blood gases (ABG) and pulsatile oxygen.

what are the 2 readings on a pulse oximeter?

When you breathe normal room air at your normal respiratory rate, you should have an oxygen saturation somewhere between 95 and 100 percent and a pulse rate between 60 and 100.

This means that your heart beats normally while carrying enough oxygen to the rest of your body. to keep you healthy. If one or both of these numbers are outside the normal limits, it is an indicator that something is wrong and is preventing your body from effectively oxygenating your bloodstream.

Pulse oximeter oxygen saturation

Using red and infrared light sources and a light sensor, pulse oximeters determine the percentage of hemoglobin (red blood cells) in your bloodstream that is carrying oxygen to various parts of your body.

Pulse oximeter heart rate

The blood is not stagnant in your veins. Therefore, it is almost impossible to synchronize a pulsed light with your heart rate to determine your blood oxygen saturation.

Instead, a pulse oximeter uses a constant stream of light to measure absorption and a sophisticated calculation to measure “pulsed absorbance” while filtering out interference from muscles, and tissues. Since it only measures oxygen uptake during blood flow, it reads a pulse rate in addition to oxygen saturation

More on this story

Pulse Oximeters: Answering Your Frequently Asked Questions

What are the 2 readings on a pulse oximeter

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