Arterial Oxygen Content Study Guide is a series of multiple choice question designed to solve for every possible variable in the calculation.
  • The arterial oxygen content (CaO2) definition is the amount of oxygen bound to hemoglobin (1.34 * Hb * SaO2) plus the oxygen dissolved in plasma (0.0031 * PaO2).
  • The arterial oxygen content equation: CaO2 = (1.34 * Hb * SaO2) + (0.0031 * PaO2).
  • The normal oxygen combining capacity is 1.39 mls/gram, however due to abnormal forms of hemoglobin such as carboxyhemoglobin and methemoglobin this value is reduced to 1.34 mls/gram.
  • Hgb is Hemoglobin, the normal Hgb for males is 14-20 g/dl and females 12-15 g/dl. Hgb expressed as g/dl is equivalent to g Hgb/100 mL of Blood.
  • 0.0031 is the solubility coefficient of oxygen at body temperature.
  • Note: “vol%” is equivalent for “ml O_2/100 ml blood”.


1. Given the following Hgb = 17g Hgb/100 ml blood,  SaO2=90%, PaO2= 100 mmHg. Calculate Arterial Oxygen Content (CaO2).

A. 15.15 vol%
B. 20.81 vol% 
C. 20.5 vol%
D. 11.35 vol%

Answer: B.

 2. Given the following,  SaO2 = 92%, PaO2 = 90 mmHg, and  CaO2 = 19.80 Vol%. What is Hgb?

A. 17.23 g Hgb/100ml Blood
B. 15.87 g Hgb/100ml Blood
C. 20.85 g Hgb/100ml Blood
D. 21.37 g Hgb/100ml Blood

Answer: B. 

 3. Given the following,  Hgb =17 g Hgb/100ml Blood, PaO2 = 100 mmHg, and  CaO2 = 16.80 Vol%. Calculate SaO2.

A. SaO2 = 62% 
B. SaO2 = 72% 
C. SaO2 = 82% 
D. SaO2 = 92% 

Answer: B.

 4. Given the following, Hgb = 19 g Hgb/100ml Blood, SaO2 = 95 mmHg, and  CaO2 = 16.80 Vol%. Calculate PaO2?

A. 93.87 mmHg
B. 88.47 mmHg
C. 72.88 mmHg
D. 83.87 mmHg

Answer: D.

NBRC RRT exam review

To Much to do? Not enough time? Don't know where to begin?

We help struggling RRT students who are short on time and have trouble with test taking and memorization. Build confidence so you can excel in class and pass you NBRC RRT Board Exams!