1 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Chapter 3 Pulmonary Function Study Assessments Pulmonary Function Study Assessments

2 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Introduction  Pulmonary function studies are used to:  Evaluate pulmonary causes of dyspnea  Differentiate between obstructive and restrictive pulmonary disorders  Assess severity of the pathophysiologic impairment  Follow the course of a particular disease  Evaluate the effectiveness of therapy  Assess the patient’s preoperative status

3 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Normal Lung Volumes and Capacities

4 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Table 3-1. Lung Volumes and Capacities of Normal Recumbent Subjects 20 to 30 Years of Age

5 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Table 3-2. Restrictive Lung Disorders: Lung Volume and Capacity Findings

6 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Table 3-4. Obstructive Lung Disorders: (Lung Volume and Capacity Findings)

7 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Table 3-5. Anatomic Alterations of the Lungs Associated with Obstructive Lung Disorders: (Pathology of the Tracheobronchial Tree)

8 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-1. Visual comparison of lung volumes and capacities in obstructive and restrictive lung disorders. (From Wilkins RL, Stoller JK, Scanlan CL: Egan’s fundamentals of respiratory care, ed 9, St Louis, 2009, Elsevier.)

9 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Indirect Measurements of the Residual Volume and Capacities Containing the Residual Volume  Closed-circuit helium dilution test  Open-circuit nitrogen washout test  Body plethysmography

10 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Forced Expiratory Flow Rate and Volume Measurements

11 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Forced Vital Capacity (FVC)  The FVC is the total volume of gas that can be exhaled as forcefully and rapidly as possible after a maximal inspiration.

12 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-2. Forced vital capacity (FVC). A is the point of maximal inspiration and the starting point of an FVC maneuver. Note the reduction in FVC in obstructive pulmonary disease.

13 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Forced Expiratory Volume (FEV T )  The maximum volume of gas that can be exhaled over a specific period is the FEV T.  This measurement is obtained from an FVC measurement.  Commonly used time periods are 0.5, 1.0, 2.0, 3.0, and 6.0 seconds  The most commonly used time is 1 second (FEV 1 ).

14 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-3. Forced expiratory volume timed (FEV T ). In obstructive pulmonary disease, more time is needed to exhale a specified volume.

15 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Forced Expiratory Volume (FEV T ) (Cont’d)  In the normal adult, the percentage of total volume exhaled during these time periods:  FEV 0.5 : 60%  FEV 1 : 80%  FEV 2 : 94%  FEV 3 : 97%

16 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Forced Expiratory Volume in 1 Second/Forced Vital Capacity Ratio (FEV 1 /FVC Ratio) (also abbreviated as FEV 1% )

17 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. FEV 1 /FVC Ratio or FEV 1%  The FEV 1 /FVC ratio compares the amount of air exhaled in 1 second with the total amount exhaled during an FVC maneuver.

18 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. FVC, FEV 1, and FEV 1%  Clinically, the FVC, FEV 1, and FEV 1% are commonly used to: 1. Assess the severity of a patient’s pulmonary disorder and 2. Determine whether the patient has an obstructive or a restrictive disease

19 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. FVC, FEV 1, and FEV 1% (Cont’d)  The primary pulmonary function study difference between an obstructive and a restrictive lung disorder are as follows:  In an obstructive disorder, the FEV 1 and FEV 1% are both decreased.  In a restrictive disorder, the FEV 1 is decreased and FEV 1% is normal or increased.

20 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Forced Expiratory Flow 25%-75%  The FEF 25%-75% is the average flow rate generated by the patient during the middle 50% of an FVC measurement.  FEF 25%-75% is used to evaluate the status of medium-to-small airways in obstructive lung disorders.

21 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-4. FEF 25%-75%. This test measures the average rate of flow between 25% and 75% of an FVC.

22 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Forced Expiratory Flow  The FEF measures the average flow rate between 200 and 1200 mL of an FVC.  The FEF provides a good assessment of the large upper airways.

23 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Forced Expiratory Flow (Cont’d)  The FEF measures the average flow rate between 200 and 1200 mL of an FVC.  The FEF provides a good assessment of the large upper airways.

24 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-5. FEF This test measures the average rate of flow between 200 mL and 1200 mL of an FVC.

25 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Peak Expiratory Flow Rate  The PEFR is the maximum flow rate generated during an FVC maneuver.

26 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-6. PEFR. The steepest slope of the  V/  T line is the PEFR (V). ˙˙

27 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Maximum Voluntary Ventilation (MVV)  The MVV is the largest volume of gas that can be breathed voluntarily in and out of the lungs in 1 minute.  Note: The patient effort during the MVV is for only 12 to 15 seconds. The total 1 minute MVV is extrapolated from these data.

28 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-7. Volume-time tracing for an MVV maneuver.

29 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Flow-Volume Loop  The flow-volume loop is a graphic illustration of both a forced vital capacity (FVC) maneuver and a forced inspiration volume (FIV) maneuver.

30 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Flow-Volume Loop (Cont’d)  Depending of the sophistication of equipment, several important pulmonary function study values can be obtained, including: FVC FVC FEV T FEV T FEF 25%-75% FEF 25%-75% FEF FEF PEFR PEFR Peak inspiratory flow rate (PIFR) Peak inspiratory flow rate (PIFR) FEF 50% FEF 50% Instantaneous flow at any given lung volume during forced inhalation and exhalation Instantaneous flow at any given lung volume during forced inhalation and exhalation

31 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-8. Flow-volume loop.

32 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-9. Flow-volume loop demonstrating the shape change that results from an obstructive lung disorder. The curve on the right represents intrathoracic airway obstruction.

33 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure 3-7. Volume-time tracing for a maximum voluntary ventilation (MVV) maneuver. Note: the patient actually performs the MVV maneuver for only 12 sec, not 60 sec.

34 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Figure Flow-volume loop demonstrating the shape change that results from a restrictive lung disorder. Note the symmetric loss of flow and volume.

35 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Table 3-8. Obstructive Lung Diseases: Forced Expiratory Flow Rate and Volume Findings

36 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Pulmonary Diffusion Capacity  The pulmonary diffusion capacity of carbon monoxide (D LCO ) measures the amount of carbon monoxide (CO) that moves across the alveolar-capillary membrane.

37 Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Table 3-9. Pulmonary Diffusion Capacity of Carbon Monoxide (D LCO )