Oxygen Saturation levels and what do they mean?

oxygen saturation

What should my oxygen saturation level be?

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.

Oxygen saturation levels – what do they mean?

Oxygen saturation levels measure the degree to which the haemoglobin contained in the red blood cells (erythrocytes) 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 does an ABG measure?

An ABG test measures how efficiently your lungs are bringing oxygen into the blood stream and removing carbon dioxide. Arterial blood gases are taken from an artery usually on the wrist. This procedure can be a little painful. The critical oxygen blood level is 55-60mmHg (SaO2), with readings below this level indicating the person is underoxygenated.

What does a pulse oximeter measure?

A pulse oximeter indirectly measures oxygen saturation levels. This non invasive process involves inserting a finger (can be used on the ear or a toe as well) into the device where a red light calculates the redness of the blood pulsing through the finger. The pulse oximeter measures the haemoglobin providing a mean saturation percentage (SpO2). A SpO2 of 90% (equivalent to SaO2 of 55-60mmHg) is considered to be the critical level. The underlying principle of the oximeter is that it measures the redness of the blood – the redder the blood the higher the oxygen saturation.

More In-depth explanation about Pulse Oximeter and Oxygen Saturation level. 

Living with lung disease such as COPD emphysema and lung fibrosis can be a struggle. However you can live in the enjoyable life filled with quality by following a simple daily routine includes good self-care.

If you require medical oxygen there are portable and stationary systems to meet your oxygen needs which can minimize the inconvenience associated with oxygen therapy.

In this article we describe and demonstrate how a pulse oximeter like this one can be used to measure your oxygen level to adjust your oxygen study and to inform your doctor of a change in your condition. In addition the oximeter can be used as a biofeedback training device along with pursed lips breathing to increase your oxygen level.

Your need for oxygen

Your need for oxygen is continuous, the human body requires oxygen and food and water to create energy and fuel our active lives oxygen has to be brought in from the outside air and carried to each and every cell each and every minute. This is a continuous path of transport systems, your lungs deliver oxygen into your bloodstream, your heart pumps the blood to the tissues or oxygen is delivered to every cell. Each cell has a manufacturing system called mitochondria, that uses oxygen and food to create energy for the muscles to power the body, carbon dioxide the waste product of this process is expelled. Oxygen is required constantly by every tissue of your body to create the energy of life.

There is plenty of oxygen in the atmosphere to meet the needs of people with normal lungs. However if you have lung disease, you may need extra oxygen to meet your body’s oxygen requirements, you may have been diagnosed with COPD or lungs fibrosis. COPD is the combination of bronchitis, asthma and emphysema while lung fibrosis is the build up of scar tissue that impedes the transfer of oxygen across the alveolar capillary membrane.

 

Determining Your Need For Oxygen

Your doctor will prescribe oxygen based on the level of oxygen in your bloodstream during the rest, exertion and sleep. Oximetry is the most convenient method of testing your oxygen level. Your oximeter tells how much of your blood is filled with oxygen, your S.P.O2 oximetry reading is an important piece of information but it does not stand alone, combined with other information, you and your doctor can make important decisions to guide your self-management program.

How Your Body Gathers Oxygen

The diaphragm pulls down and the chest muscles pull out to lengthen and widen the chest to make room for air to enter the lungs. Oxygen in the air reaches the expanding alveoli or air sacs where network of tiny blood vessels called capillaries receives the oxygen as it diffuses across the alveolar capillary membrane, at the same time carbon dioxide which is produced in the body’s cells and carried on the haemoglobin molecule, the red blood cell detaches and defuses across the alveoli capillary membrane to be exhaled through the atmosphere. Once in the blood oxygen quickly attaches to the haemoglobin molecule of the red blood cell, turning it red. Freshly oxygenated blood is pumped by the heart through the major arteries towards the vital organs muscles and other, reaches delivering oxygen to each and every cell once inside the cell, oxygen finds its way to the mitochondria which uses the oxygen to create energy.

Carbon dioxide the end product of the body’s metabolism is carried by the blood stream to the lungs where it is exhaled to the atmosphere, thus completing one of millions of cycles that sustain life.

Measuring Your Oxygen Level

As your red blood cell gathers oxygen onto the haemoglobin molecule, it turns red. Oximetry is based upon the redness of the blood, as the blood’s capacity to contain oxygen becomes filled the blood turns more red.

The oximeter functions by shining two lights, red and infrared through your finger, sensors on the other side of your finger detect how much of each light is passing through. The red light measures un-oxygenated haemoglobin whereas the infrared light measures oxygenated haemoglobin. A tiny computer inside the oximeter compares the two lights and displays a number on the screen that tells what percentage of haemoglobin is saturated with oxygen.

The oximeter is designed to take its reading at the peak of the pulse where the blood contains the most oxygen and any other point on the pulse there is less oxygenated blood causing in inaccurate reading. Thus it is imperative to make sure that the oximeter is detecting regular pulses, now most oximeter have either a display or pulse indicator that informs you of regular pulses. The normal oxygen level is about ninetyfive to ninety seven percent at sea level but ninety percent is just barely acceptable.

Oximeter compared to ABGs

Arterial blood gases measure your oxygen saturation level by drawing blood from your artery. It’s the most accurate measurement of your oxygen saturation level and it also measures your carbon dioxide and provides other useful information. On the down side it’s invasive and involves a needle stick and it measures only a single point in time. Oximetry measures only oxygen but it does so non-invasive and continuously. It is not invasive, inexpensive useful during exercise and sleep, patients can use it at home or anywhere and patients can use it to learn how to increase their oxygen level.

Position the accelerator clip on your finger keeping your finger steady, wait for a strong steady pulse and consistent SPO2 then take your reading. Avoid Dark nail polish or artificial nails, don’t tighten your head as it may cut off the circulation to your finger. Avoid excessive movement of your finger that might give a false reading, here’s some suggestions, if the pulse is week try running warm water of your hand to increase the blood flow or re position the oximeter, during exercise try steady using your finger Before taking the reading, relax your hand to maximize blood flow. An important point there is a lag time for any change in your blood oxygen to reach your finger. So be sure to wait for twenty to thirty seconds before taking your final reading.

Oximetry During Exercise

If you have lung disease daily exercise such as walking is an important part of maintaining your health. Exercise is essential to active living, whether you exercise or simply move around you raise your body’s metabolism, consequently you require more oxygen when you are active. Your doctor would determine your oxygen need during exercise, your oximeter will let you know if your oxygen level is adequate during exercise or activity.

When you exercise bodily movement may cause false oximetry readings, therefore try keep your finger steady when taking the reading, make sure that the oximeter is showing a strong and regular pulse. Exercising bodies require more oxygen, when you increase your activity, your oxygen level may drop therefore your resting oxygen setting may be inadequate to meet your body’s needs during exercise, that saturation drop may be the reason you had to stop exercising. In order to detect the lower oxygen level, keep reading the oximeter for about thirty seconds after you stop exercising, your saturation may continue to drop.

Report low oxygen readings to your doctor and give instructions on adjusting your oxygen setting during exercise. It’s important that you are able to maintain adequate oxygen levels during exercise.

Airplanes are pressurized to five thousand to eight thousand feet and sometimes higher, not to sea level, this is equivalent to Denver’s attitude or even higher, if you need oxygen on the ground, you will definitely need oxygen during air flight, sometimes you don’t require oxygen on the ground but do need oxygen during Air flight, your doctor will make that determination, make sure that you plan your travel at least two to three weeks ahead of time and inform the airline that you will be requiring oxygen, each airline has its own set of procedures for oxygen. You can buy oxygen from the airline, however it is better to run a portable oxygen concentrator from your oxygen supplier such as EasyOxygen Australia with branches all over Australia. Your doctor will write an oxygen prescription, a copy of which will go to the airline in another copy will go to your oxygen company.

On the flight your oximeter will tell you if your oxygen setting is adequate. In Pulmonary rehabilitation, we teach a breathing technique called pursed lips breathing which can increase your oxygen level, breathe in through your nose and exhale slowly through your mouth while pursing your lips. Think of it this way, smell the roses and gently blow the candle causing the flame to flicker, in through your nose and out through pursed lips. If you use your oximeter as a guide while doing pursed lips breathing, you can learn to raise your oxygen level by as much as three to four points. Just focus on the oximeter while doing pursed lips breathing, if you are successful your oxygen level will increase. Pursed lips breathing with oximetry is especially useful when active and exercising. It is important to remember that it takes time for the blood to travel from your lungs to your finger oximeter. So wait for about twenty seconds to determine if there is a change in your oximetry reading. Be persistent practice makes perfect.

Control over your lung disease is determined by how you manage at home, taking your medication and oxygen properly, keeping your airways clear, exercising and monitoring for an infection or a flare up of your illness. We all make a major difference on how your lung disease affects you. When there is any change in your condition it is crucial that you call your doctor, some doctors provide their patients with a rapid action plan to be initiated in case of signs or symptoms of infection, the signs are more shortness of breath, cough with sputum and a change in your oximetry reading and these may signal an infection, a flare up at which time you may need antibiotics, prednisolone and inhalers as well as a change in your oxygen setting. This will be determined and prescribed by your doctor.

Summary

It is essential for you to obtain a quality oximeter and use it correctly, your oxygen needs are greater when you are active, exercising at higher altitudes or up in an airplane, therefore you should monitor your oximetry during each of these conditions, a change in your oximetry level may signal a change in your condition or even a flare up and the need to call your doctor. Practice your purse lipped breathing with oximeter as a guide to increase your oxygen level. Use your oximeter in good health and as directed by your doctor.

Watch the related video on how to use Pulse Oximeter
(Oximeter shown in this video is not the actual EasyOxygen Pulse Oximeter)

Factors impacting on pulse oximeter readings

Dirty fingers, nail polish, bright lights and poor circulation to the extremities will all alter the accuracy of a pulse oximeter reading.

So, which is better, arterial blood gases or pulse oximeter measures?

The pulse oximeter provides a quick indication of blood saturation levels, however the arterial blood gases will give the most accurate measure.

Content Package includes:

  • Fingertip  Pulse Oximeter, 1 unit
  • User guide (user manual) , 1 sheet
  • Quick reference card, 1 piece
  • Warranty Card, 1 piece
  • AAA-Size Alkaline Battery , 1 piece

The EasyOxygen Fingertip Oximeter (AT01 Seies ) is intended for measuring functional oxygen saturation of arterial hemoglobin (Sp02) and pulse rate for both adult and children as non-invasive spot checking in home and professional caring environment. It is designed for fingers between 0.8cm and 2.3cm (0.3 inch – 0.9 inch ) and for patients during no-motion condition.

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