Question

Sue Hogan, age 50 years, was diagnosed with idiopathic pulmonary fibrosis (IPF) two years ago. IPF is a chronic, progressive lung disease with no cure. It results in fibrotic scarring and thickening of lungs tissue, impairing oxygen delivery. Despite her diagnosis, Sue continues to work full time at her job, taking the commuter train daily. However, over the past few weeks the demands of activities of daily living have become increasingly difficult. She complains of being tired, persistent dry cough, and extreme shortness of breath when climbing a flight of stairs. She had to take a medical leave from her job. The following information was obtained at her recent physical examination.

Arterial Blood Gases At Rest
PaO2	76 mm Hg
PaCO2	37 mm Hg
% Hgb Saturation	97%

Calculate the total O₂ content of Sue’s blood while she is at rest. Assume that the O₂-binding capacity of her blood is 1.34 ml O₂/gm of hemoglobin, her hemoglobin concentration is 15 gm/dl, and the solubility of O₂ in blood is 0.003 ml O2/100 ml blood/mm Hg.

Answer 1

Calculating arterial oxygen content:

CaO2 = (Hb x 1.36)( Sa02$\div$ 100) +( PaO2 x0.0031)

CaO2 = arterial oxygen content (ml/dl)

Hb =hemoglobin (g/dl)

PaO2 = arterial oxygen tension( mm Hg)

SaO2 = arterial oxygen saturation (%)

oxgen binding capacity given = 1.34 ml O2/g

Arterial oxgyen content(CaO2) = (15 x 1.34)(97$\div$100) + (76 X 0.0031)

=(20.1)(0.97) + 0.2356

=19.497 + 0.2356

=19.7326

=20 ml/dl