Alveolar Gas Equation Practice Questions

1.      A patient is receiving 55% FiO2 on a day when the barometric pressure is 685 mm Hg. A blood gas shows that the PaCO2 is 45 torr. What is the patients PAO2?

2.      A patient comes to the clinic in respiratory distress. The blood gas shows a PaCO2 of 56 torr, while the patient is breathing room air. If the barometric pressure is 702 mmHg, what is the PAO2?

3.      A patient is on a nasal cannula at 2LPM. A blood gas shows a PaCO2 of 42. If the barometric pressure is 740, what would you calculate the PAO2 to be (hint: what is FiO2 estimated at 2LPM).

4.      A 27-year-old young woman came to the emergency room complaining of pleuritic chest pain of several hours duration. Her chest x-ray and physical exam were normal except for splinting with deep inspirations. Arterial blood gas showed pH: 7.45, PaCO2: 31 mm Hg, HCO3-: 21 mEq/L, PaO2: 83 mm Hg (breathing ambient air; PB: 747 mm Hg).  Calculate the PAO2 (Sift through all the unnecessary numbers and information!).

5.      A 60-year-old male with COPD is an air entrainment device set at 42%. The blood gas shows a PaCO2 of 60. If the barometric pressure is 730 mmHg, what is the PAO2?

LINK TO ONLINE CALCULATOR:
This link allows you to plug in values and check your work:
https://www.easycalculation.com/medical/alveolar-gas-equation.php

References:

Alveolar gas equation calculator. (n.d.). Retrieved March 11, 2017, from https://www.easycalculation.com/medical/alveolar-gas-equation.php