What is the cardiac output when O2 consumption = 180 mL/min, arterial O2 content = 18.4 vol%, and mixed venous O2 content = 14.4 vol%

a. 4.5 mL/min c. 6.5 mL/min
b. 5.5 mL/min d. 7.5 mL/min

ANS: A
Cardiac output = oxygen consumption ÷ (arterial O2 content – mixed venous O2 content). 18.4 vol% = 18.4 mL/100 mL and 14.4 vol% = 14.4 mL/100 mL. Therefore, 180 mL/min ÷ (18.4 mL/100 mL – 14.4 mL/100 mL) 10 = 4.5 mL/min.