About oxygen level
A normal oxygen level in a healthy individual is usually 95% or higher. While people with chronic respiratory disease or sleep apnea can have an oxygen level below 90%. However, usually below this range, a person may require oxygen support via mechanical ventilation. An oxygen level below 80% is very critical and can be fatal.
Mechanical ventilation is given by a machine called a ventilator, which is attached to an oxygen source and a face mask through which the oxygen is given. The biggest example is the covid-19 surge that has increased the demand for ventilators in a very short time.
What does it mean by oxygen levels?
Our red blood cells have a high affinity towards oxygen and acquire oxygen from the atmosphere. Thus, oxygen levels determine how much oxygen red blood cells are carrying. Oxygen-saturated blood is crucial for health. A decline in oxygen levels can result due to severe respiratory conditions such as asthma, heart diseases, chronic obstructive pulmonary disease or chest pain.
In simple words, any obstruction in the respiratory system interferes with the normal oxygen intake causing a fall in oxygen levels.
Some possible conditions may cause oxygen levels down:-
- Chronic pulmonary obstructive disease with bronchitis and emphysema
- Collapsed lungs
- Congenital heart defects
- Acute respiratory distress syndrome
- Pulmonary embolism
The above conditions interrupt the lungs from adequate inhaling oxygen and exhaling carbon dioxide. Thus, declines oxygen levels and the person starts feeling symptoms of hypoxemia.
How the oxygen levels are adjusted?
If the oxygen levels are below normal, the person requires supplemented oxygen which is given by a ventilator.
How oxygen levels are measured?
The oxygen levels can be measured by two methods:-
- ABG (arterial blood gas)
The ABG test is a blood test and measures blood’s oxygen levels. It’s an invasive procedure and includes blood drawing from the arteries. It can also detect the levels of other gases and pH levels. The blood is taken from the wrist artery, as it can be felt easily as compared to the other parts.
- Pulse oximeter
It’s a non-invasive oxygen measuring device that detects the oxygen levels in your blood. It recognizes the oxygen levels by sending infrared light into capillaries of the finger, earlobe or toe. The monitor shows the reading or the percentage of oxygen saturated blood, known as the SpO2 levels.
However, the process may be less accurate but is easy to use whenever required. As the device is non-invasive, the person can check oxygen levels himself.
What does your reading show?
Different readings show different conditions. PaO2 (partial pressure of oxygen) is used when using a blood gas and SpO2 while using a pulse oximeter.
Normal:- a normal range of ABG oxygen levels for healthy lungs is between 80-90 mm Hg. if a pulse oximeter is used, the normal reading falls between 95-100 percent. These readings may not be normal in people with respiratory disorders.
Below normal:- a below-normal level of oxygen is called hypoxemia. Generally, a PaO2 reading below 80mm Hg or a SpO2 below 95 per cent is considered below abnormal.
Above normal:- it is not possible naturally. If someone is under supplemental oxygen can have a high level of oxygen. The above-normal oxygen levels are detected by ABG.