Oxygen Content Calculator
Determines arterial oxygen based on haemoglobin, O2 saturation and arterial pressure.
You can read more about the variables and the formula used in the text below the form.
The oxygen content calculator uses the haemoglobin levels in g/dL, the percentage of oxygen saturation and O2 arterial pressure in mmHg, to determine the arteria oxygen content.
Arterial Oxygen Content = Hemoglobin x 1.36 x SaO2 /100 + 0.0031 x PaO2
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Steps on how to print your input & results:
1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.
2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.
Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.
Variables and formula
Arterial blood oxygen is the measure of the oxygen in 100 ml of blood both bound or unbound by hemoglobin.
It offers information about the uncombined part of oxygen which can become of interest at high values of PaO2 or in patients diagnosed or suspected of anemia.
The three variables used are described in the table below:
| Variable | Normal values | Description |
| Hemoglobin | 13.8 - 17.2 g/dL for men 12.1 - 15.1 g/dL for women |
Complex protein on the RBCs, involved in oxygen transport |
| SaO2 | Between 95 and 100%. | Arterial blood-oxygen saturation, determined during pulse oximetry |
| PaO2 | 75 and 100 mmHg | Arterial pressure of oxygen |
The following formula is employed:
Arterial Oxygen Content = Hemoglobin x 1.36 x SaO2 / 100 + 0.0031 x PaO2
This can be explained as: CaO2 is the amount of oxygen bound to hemoglobin (1.36 x Hb x SaO2) plus the oxygen dissolved in plasma (0.0031 x PaO2).
The 1.36 constant represents the amount of oxygen (ml at 1 atmosphere) bound per gram of hemoglobin.
In some cases, the 1.36 constant is reduced to 1.34 because of abnormal forms of hemoglobin such as carboxyhemoglobin and methemoglobin.
The dissolved oxygen constant (0.0031) becomes of relevance at very high PaO2 (as in a hyperbaric chamber) or in severe anemia.
References
1. Anthea M, Hopkins J, McLaughlin CW, Johnson S, Warner MQ, LaHart D, Wright JD. Human Biology and Health. Englewood Cliffs NJ: Prentice Hall, 1993.
2. Stoelting RK, Pharmacology & Physiology in Anesthetic Practice, Lippincott Williams & Wilkins, 1999.
3. Hsia CC. Respiratory function of hemoglobin. N Engl J Med. 1998; 338(4):239-47.
Specialty: Pulmonology
System: Respiratory
Objective: Determination
Type: Calculator
No. Of Variables: 3
Article By: Denise Nedea
Published On: June 7, 2017 · 09:01 AM
Last Checked: June 7, 2017
Next Review: June 7, 2023