This patient was diagnosed with Idiopathic Pulmonary Fibrosis 2 years ago after developing shortness of breath on exertion and a dry cough. There is evidence of a slight deterioration in the 6 minute walk test and pulmonary function test results over this 2 year period and symptomatically he is aware of disease progression. He is currently undergoing pulmonary rehabilitation, however, arthritis in his knees is stopping him from progressing.
On examination there is no evidence of clubbing, heart sounds are normal and auscultation of the chest revealed fine fibrotic bi-basal crackles. Resting oxygen saturations were normal (95%) but a short walk up and down the corridor resulted in a small oxygen desaturation to 92%.
What is your interpretation of these spirometry results?