A reduced oxygen content in inspired air can have serious health effects. It may occur in a variety of environmental and occupational situations.
The normal oxygen content of air is 21%.
|
Oxygen Content |
Health Effects |
|
19.5% |
none (minimum level for safe exposure) |
|
16% |
impaired judgment; impaired breathing |
|
14% |
faulty judgment; rapid fatigue |
|
5% |
difficulty breathing; death in minutes |
partial pressure of oxygen in mm Hg =
= (atmospheric pressure in mm Hg) * (percent oxygen content as a whole number) / 100
According to deJong and Adams, there are 4 stages of oxygen depletion:
|
Oxygen Content |
Signs or Symptoms |
Stage |
|
21% |
none |
NA |
|
16 - 21% |
none; can work or exercise without distress |
0 |
|
12 - 16% |
breathing rate and pulse are increased |
1 |
|
10 - 14% |
disturbed respirations; conscious but may be emotionally upset; abnormal fatigue with exertion |
2 |
|
6 - 10% |
nausea and vomiting; unable to move freely; unable to move or cry out; may collapse or become unconscious; |
3 |
|
< 6% |
gasping respirations; convulsive movements; cardiopulmonary arrest |
4 |
If toxic gases are also present, then the health effects may be even more pronounced.
A person entering an area with reduced oxygen content may require use of a positive pressure, self-contained breathing apparatus.
Specialty: Pulmonology
ICD-10: ,
