Relation between Oxygen Saturation and Partial Pressure
The relation between oxygen saturation (SpO2 ) and oxygen partial pressure (PaO2) is shown in the graph below. SpO2 is the
oxygen saturation as measured by pulse oximeters.
■Oxygen Saturation vs. Oxygen Partial Pressure
%
100
90
85
80
70
60
50
40
SpO2 30
20
10
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| pH=7.4 |
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| 37°C |
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0 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 |
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| PaO2 |
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| Torr | |
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| (mmHg) |
Appendix
The curve of the above graph may shift to the right or left according to the pH of the blood or the body temperature.
•Shift to right: acidosis, high body temperature
•Shift to left: alkalosis, low body temperature
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