Normal oxygen levels

Oxygen Levels

Oxygen is very important for the survival of humans. When a person breathes, he/she inhales the air. One of the ingredients of the air is oxygen. The respiratory system, especially the lungs, is important for the storage of oxygen.

On the other side, the circulatory system also plays an important role in distributing oxygen throughout the body through the bloodstream. The pulmonary arteries carry deoxygenated blood from the heart to the lungs, where the blood takes the oxygen and through the pulmonary veins brings the oxygenated blood to the heart, which is then distributed to all parts of the body.

The levels of oxygen represent the levels of saturated oxygen in the blood. Oxygen levels are very important since they can indicate certain problems with the lungs and also the levels of hemoglobin in the blood.

Furthermore, the infections present in the body or the respiratory diseases can be discovered through a good interpretation of the levels of oxygen in the blood. Many other factors cause the change in the levels of oxygen, such as the pH of the blood and even the altitude at which a person lives.

Oxygen saturation has been shown in risk score models to predict mortality in emergency medicine. The aim of this study was to determine whether low oxygen saturation measured by a single-point measurement by pulse oximetry (SpO2) is associated with increased mortality in the general adult population.

Pulse oximetry was performed in 5,152 participants in a cross-sectional survey in Tromsø, Norway, in 2001–2002 (“Tromsø 5”).
Ten-year follow-up data for all-cause mortality and cause of death were obtained from the National Population and the Cause of Death Registries, respectively. Cause of death was grouped into four categories: cardiovascular disease, cancer except lung cancer, pulmonary disease, and others. SpO2 categories were assessed as predictors for all-cause mortality and death using Cox proportional-hazards regression models after correcting for age, sex, smoking history, body mass index (BMI), C-reactive protein level, self-reported diseases, respiratory symptoms, and spirometry results.
The mean age was 65.8 years, and 56% were women. During the follow-up, 1,046 (20.3%) participants died. The age- and sex-adjusted hazard ratios (HRs) (95% confidence intervals) for all-cause mortality were 1.99 (1.33–2.96) for SpO2???92% and 1.36 (1.15–1.60) for SpO2 93–95%, compared with SpO2???96%.
In the multivariable Cox proportional-hazards regression models that included self-reported diseases, respiratory symptoms, smoking history, BMI, and CRP levels as the explanatory variables, SpO2 remained a significant predictor of all-cause mortality. However, after including forced expiratory volume in 1 s percent predicted (FEV1% predicted), this association was no longer significant.
Mortality caused by pulmonary diseases was significantly associated with SpO2 even when FEV1% predicted was included in the model.

✓ Fact confirmed: Low oxygen saturation and mortality in an adult cohort: the Tromsø study Monica Linea Vold, Ulf Aasebø, Tom Wilsgaard, and Hasse Melbye; 2015 Feb 12.

Normal Oxygen Levels in Blood

The normal oxygen level is considered to be from 95% to 100%. With this oxygen level, the body cells can function smoothly. However, if the level of oxygen is below the normal level, it may be serious.

The level of oxygen can be measured in various ways. However, in the majority of cases, the level of oxygen is measured using a blood test, which is called an arterial blood gas test. A pulse oximeter may be also used for measuring oxygen levels.

Hypoxemia is the condition when the oxygen levels are below 90% and this condition is usually marked by the appearance of bluish skin.

Normal Oxygen Levels in Children

When the oxygen level is measured in children, it is a painless procedure. The normal levels of oxygen in children are considered to be at least 97%. This percentage is also considered to be borderline to normal, and it means that even 97% of the bloodstream must be oxygen saturated.

When one is sleeping, he/she has lesser levels of oxygen and that is normal. However, some people can develop sleep apnea, which is characterized by a considerable drop in the levels of oxygen while sleeping. When the levels of oxygen are changed in the blood, it always indicates that a certain disorder is present in the body.