Diffusing Capacity -Equipment / Report Interpretation

1. Diffusing Capacity -Equipment / Report Interpretation RET 2414L Pulmonary Function Testing Module 4.0

2. Diffusing Capacity • DLcosb • Assignment of Severity Normal 80-120% of Predicted Mild 60-79% of Predicted Moderate 40-59% of Predicted Severe 20-39% of Predicted Very Severe <20% of Predicted Taken from “Pulmonary Function Testing and Cardiopulmonary Stress Testing” by Vincent C. Madama

3. Diffusing Capacity • DLcosb • DL/VA • DLco is directly related to lung volume in healthy individuals • DL/VA is approximately 4-5 ml CO transferred/minute/liter of lung volume

4. Diffusing Capacity • DLcosb • DL/VA • DL/VA is useful in differentiating between restrictive and obstructive disease • Obstruction = Low DL/VA ratio • Restriction = DL/VA Ratio is preserved

5. Case Study 5 – 1 History P.M. is a 55-year-old woman referred to the pulmonary function laboratory because of shortness of breath on exertion. She a 38-pack-year smoking history, but stopped smoking 6 months ago. She still coughs each morning, but her sputum volume has decreased since she stopped smoking. She has no significant environmental or family history of pulmonary disease. She had been using an inhaled -agonist but withheld it for 12 hours before the test.

6. Case 5 – 1 Personal Data Age: 55 Height: 65 Weight: 137 lb Race: African American

7. Case 5 – 1 Spirometry Pred Act %Pred Post %Pred % FVC (L) 2.89 2.77 96 2.82 98 2 FEV1 (L) 2.30 1.91 83 2.01 87 5 FEV1% 80 69 - 71 - FEF 25%-75% 2.33 1.44 62 1.51 65 5 PEF 6.08 4.01 66 5.13 84 28

8. Case 5 – 1 Lung Volumes Pred Act %Pred TLC (L) 4.39 4.97 113 FRC (L) 2.45 3.10 127 RV (L) 1.58 2.20 139 VC (L) 2.89 2.77 96 IC (L) 1.94 1.87 96 ERV (L) 0.87 0.90 103 RV/TLC% 36 44 -

9. Case 5 – 1 Diffusing Capacity Pred Act %Pred DLcosb 19.7 10.0 51 DLco (corr) 18.1 10.0 55 VA (L) 4.39 3.99 91 DL/VA 4.49 2.51 46 Hb (g/dl) 11.0