1. Lung Volumes and Gas Distribution - Report Interpretation RET 2414L Pulmonary Function Testing Module 3.0

2. Lung Volumes / Gas Distribution  Lung Volumes The most significant volumes for evaluating the effects of pulmonary disorders are VC, FRC, RV, and TLC

3. Lung Volumes / Gas Distribution  RV and TLC Determination Determination of RV and TLC are based on the FRC from indirect spirometry and volumes measured during direct spirometry RV = FRC – ERV or RV = (FRC+IC) - VC TLC = FRC + IC or TLC = (FRC – ERV) + VC

4. Lung Volumes / Gas Distribution  Lung Volume Changes Restrictive patterns Obstructive patterns Demonstrate reductions in ALL lung volumes Demonstrate increases in only some lung volumes Exception: VC may be normal or even decreased

5. Lung Volumes / Gas Distribution  Significance/Pathophysiology Obstructive Pattern  Increase FRC is considered pathologic  FRC values >120% of predicted represent air trapping Emphysematous changes Obstruction caused by asthma or bronchitis

6. Lung Volumes / Gas Distribution  Significance/Pathophysiology Obstructive Pattern  Increased RV often results in a equivalent decrease in VC  Increased RV is characteristic of: Emphysema Bronchial obstruction  RV and FRC usually increase together

7. Lung Volumes / Gas Distribution  Significance/Pathophysiology Obstructive Pattern  As RV becomes larger, increased ventilation is needed to adequately exchange O2 and CO2 Requires increased VT and/or respiratory rate Work of breathing is increased Often display hypoxemia or CO2 retention

8. Lung Volumes / Gas Distribution  Obstructive Pattern Two types of obstructive patterns Increases in RV with a proportional reduction in VC; TLC remains constant (normally 80-120% of Predicted) Air Trapping

9. Lung Volumes / Gas Distribution  Obstructive Pattern Two types of obstructive patterns RV increases with little or no change in VC; TLC increased proportional to RV (TLC >120% of predicted) Hyperinflation

10. Lung Volumes / Gas Distribution  Significance/Pathophysiology Restrictive Pattern  FRC, RV and TLC typically decreased  Usually lung volumes are decreased equally  When TLC is <80% a restrictive process is present  RV/TLC is relatively normal

11. Lung Volumes / Gas Distribution  Significance/Pathophysiology Restrictive Pattern  Asbestosis  Sarcoidosis  Complicated silicosis  Neuromuscular disorders  Respiratory depression  Diaphragmatic paralysis  CHF

12. Lung Volumes / Gas Distribution  Significance/Pathophysiology Restrictive Pattern  Kyphoscoliosis  Obesity  Pleural effusion  Pneumonia  Tumor  Atelectasis  Surgical excisions

13. Lung Volumes / Gas Distribution  RV/TLC Ratio Describes the percentage of total lung volume that must be ventilated by tidal breathing

14. Lung Volumes / Gas Distribution  RV/TLC Ratio The RV/TLC ratio also known as RV/TLC% and is expressed as a percentage RV/TLC% = RV x 100 TLC In normal, young, healthy adults, the RV/TLC% ranges between 20% and 35%

15. Lung Volumes / Gas Distribution  TLC and RV/TLC Ratio RV/TLC% >35% + Normal TLC = RV/TLC% >35% + >Normal TLC = AIR TRAPPING HYPERINFLATION

16. Lung Volumes / Gas Distribution  Lung Volume Changes Patterns of Lung Volume Changes Volume Restrictive Air Trapping Hyperinflation TLCN VCN FRC RV RV/TLC%N

17. Case 3 – 1 History M.B. is a 27-year-old male high school teacher whose chief complaint is dyspnea on exertion. He states that his breathlessness has worsened over the past several months. He has smoked one pack of cigarettes per day for 10 years (10 pack years). He denies a cough or sputum production. No one in his family ever had emphysema, asthma, chronic bronchitis, carcinoma, or tuberculosis. There is no history of exposure to extraordinary environmental pollutants.

18. Case 3 – 1 Personal Data Sex:Male Age:27 yr Height:65 in Weight:297 lb Body surface area (BSA):2.28 M2

19. Case 3 – 1 Spriometry and Airway Resistance PredrugPred%Pred FVC (L)2.904.762 FEV1 (L)2.473.8664 FEV1%8582 - FEF 25%-75% 4.624.35106 FEF 50%4.945.82 85 MVV (L/M)178130137 Raw 2.330.6-2.4 SGaw 0.230.12-0.50

20. Case 3 – 1 Lung Volumes by (plethysmograph) PredrugPred %Pred VC (L) 2.904.7 62 IC (L) 1.962.91 67 ERV (L) 0.941.8 59 FRC (L)1.873.29 57 RV (L)0.931.49 57 TLC (L)3.836.2 62 RV/TLC% 2524

21. Case 3 – 2 History R. B. is a 37-year-old pipe fitter whose chief complaint is shortness of breath at rest and with exertion. His dyspnea has worsened in the past 6 months, so much so that he is no longer able to work. Additional symptoms include a dry cough. He admits some sputum production when he has a chest cold. He has smoked one pack of cigarettes per day for 19 years (19 pack years). He quit smoking approximately 3 weeks before the tests. His father died of emphysema, and his mother of lung cancer. His brother is in good health. His occupational exposure includes working for the past 13 years in the assembly room of a boiler plant. He admits to seldom using the respirators provided at work despite a dusty environment.

22. Case 3 – 2 Personal Data Sex:Male Age:37 yr Height:69 in Weight:143

23. Case 3 – 2 Spirometry Predrug Pred%PredPostdrug %Pred % FVC (L)3.045.05603.1061 2% FEV1 (L)2.033.90522.265811% FEV1%6777 -73 - FEF 25%-75% 1.34.09321.603923% FEF 50%2.125.78372.424214% FEF 25%0.782.95261.24154% MVV (L/M)8314159916510% Raw2.51 0.6-2.4 -2.47 - SGaw0.14 0.11-0.44 0.15 -

24. Case 3 – 2 Lung Volumes (by N2 Washout) PredrugPred %Pred VC (L)3.045.05 60 IC (L)1.623.18 51 ERV (L)1.421.87 76 FRC (L)2.753.81 72 RV (L)0.331.94 69 TLC (L)4.376.99 63 RV/TLC% 3028-