In order to diagnose lung diseases doctors

You Take My Breath Away Activity 5C NOTE: This activity is designed to follow You Really Are Full of Hot Air! Activity Objectives: After completing You Really Are Full of Hot Air! Activity 5B, students will conduct this structured inquiry and be able to: Identify and distinguish between obstructive and restrictive lung diseases Use decision trees to make preliminary diagnoses Measure Forced Vital Capacity (FVC) and Forced Expiratory Volume in one second (FEV 1 ) Calculate FEV 1 /FVC(%) Use Predicted Normal Value tables Calculate %predicted values Research lung diseases Prepare a presentation providing details about lung diseases Activity Descriptions: In order to diagnose lung diseases doctors Forced Vital Capacity (FVC) (the largest volume of air that can be forcibly pushed from your lungs). Forced Expiratory Volume in One Second (FEV1) (the amount of air that is pushed out of your lungs in the first second of forced exhalation). Obstructive disorders represent those in which the flow of air is impeded - FEV1/FVC ratio of less than 69%. Restrictive disorders are those in which the volume of air is reduced - FEV1/FVC ratio is normal (88% or higher). employ a variety of tests designed to measure lung health and function. By analyzing the test results, both individually and in conjunction with one another, doctors make preliminary diagnoses. In many instances decision trees and flow charts are used to help organize the various pieces of data and direct thinking. Decision trees help to focus the available information and narrow the scope of possible disease states to make the most viable diagnosis. In a previous activity, You Really Are Full of Hot Air Activity 5B, students learned how to measure basic lung capacities including Tidal Volume (TV), Vital Capacity (VC), Expiratory Reserve Volume (ERV) and Inspiratory Capacity (IC). Part 1 of this activity introduces more lung volume and flow tests. Two of these tests include Forced Vital Capacity (FVC) (the largest volume of air that can be forcibly pushed from your lungs) and Forced Expiratory Volume in One Second (FEV 1 ) (the amount of air that is pushed out of your lungs in the first second of forced exhalation). In addition, students predict values for their age and height and compare them to the measured values. To introduce the concept of how lung Activity Overview 1

diseases affect these various values students work in 3-person groups to simulate disease states and then analyze the data to identify the characteristics of obstructive and restrictive lung diseases. Once students are familiar with the measurements and the use of a decision tree, they move on to Part 2 of the activity in which they are asked to place themselves in the role of the doctor to make preliminary diagnoses of six different lung patients. First, students classify the symptoms as characteristic of obstructive or restrictive diseases. Then more detailed decision trees are used to narrow the diagnosis and determine the specific lung disease indicated by the patient symptoms and test results. After the student doctors agree upon the diagnoses, Part 3 of the activity allows students to choose one lung disease to research. Presentations about the diseases include such information as causes, treatments, affects on lifestyle and physical functioning, and possible forms of prevention. These presentations serve as a way to distribute information to other group members and as an evaluative tool. Presentation format may be assigned by you or choices may be given. Possible formats might include posters, brochures, PowerPoint presentations, newspaper articles, etc. Students may also participate in the evaluation process by peer grading one another s presentations. Activity Background: Pulmonary disorders can be classified into 2 categories - Obstructive and Restrictive Pulmonary Function Tests (PFTs) are conducted by physicians and respiratory therapists for numerous reasons including evaluation of patient lung health prior to surgery, documenting the progress of pulmonary disease, and evaluating the effectiveness of respiratory therapy. The primary focus of this activity is the use of PFTs as diagnostic tools for determining the presence and type of pulmonary disease. In addition to the PFTs described in You Really Are Full of Hot Air! (VC, TLC, FRC, and TV), this activity explores two tests most often used to diagnosis lung diseases and disorders. Forced Vital Capacity (FVC) is similar to the VC test performed previously except that the test subject is instructed to inhale maximally and exhale forcibly until no more air can possibly be expelled. In the Forced Expiratory Volume in One Second (FEV 1) test subjects receive the same instructions as for FVC but the volume measured is only that expelled in the first second of forced exhalation. Together these two tests, FVC and FEV 1, represent the most critically important measures in the diagnosis of lung diseases. 2

Pulmonary disorders are classified into two main categories, obstructive and restrictive. Obstructive disorders represent those in which the flow of air is impeded, while restrictive disorders are those in which the volume of air is reduced. Among the common obstructive disorders are asthma, emphysema, chronic bronchitis, lung cancer and cystic fibrosis. Restrictive disorders include pulmonary fibrosis; sarcoidosis; tuberculosis; neuromuscular disorders including ALS and myasthenia gravis; space reducing conditions such as obesity and pregnancy; and pneumoconiosis, a class of diseases caused by the inhalation of dusts such as asbestos and silica. Measurements used to diagnose pulmonary disorders are not the actual PFTs recorded but rather the comparison of these figures to predicted normal values. Tables detailing these values have been developed over years of research collecting PFT data from thousands of normal adults and children. Most of the spirometric equipment used by physicians and respiratory therapists includes such tables in the computer software that analyzes the test data. Several sources of actual tables can be found, however, including those adapted for this activity from McGraw-Hill s Pocket Guide to Spriometry by David P. Johns and Rob Pierce (see reference below). Diagnoses of pulmonary disorders are made based on the percent of predicted normal values represented by the measured values (measured value/predicted value X 100). In general, values over 80% in both the FVC and FEV 1 tests indicate normal lung health, or no disease. Those below 80% indicate the presence of lung disease with 65 to 80% considered mild, 50 to 65% moderate and below 50% severe dysfunction. While FVC and FEV 1 values below normal indicate the presence of a lung disorder, it is the percent of FVC represented by FEV 1 (FEV 1 /FVC (%)) that distinguishes obstructive and restrictive diseases. Since obstructive diseases are characterized by a reduction in air flow rather than volume, the FVC measurements may be close to predicted normal values but FEV 1 values will be significantly reduced. This imbalance results in a %predicted FEV 1 /FVC ratio of less than 69%. Restrictive disorders, on the other hand, are characterized by a reduction in volume rather than flow. Because both the FVC and FEV 1 readings are below predicted normal values the FEV 1 /FVC ratio is normal (88% or higher). 3

Once a disease is classified as obstructive or restrictive further test results help to refine the diagnosis to a particular disease. Included in such tests are Maximal Inspiratory Pressure (MIP), Maximal Expiratory Pressure (MEP) and Functional Residual Capacity (FRC), the amount of air remaining in the lungs at the end of a normal breath. In addition, information provided by chest X-rays often narrows the diagnosis to a particular disease. Examples of the lung diseases included in this activity and the specific test results associated with them appear below. Obstructive Lung Disorders: Emphysema FRC measurements exceeding 100% of predicted values; reduced MIP and MEP measurements; chest X-rays indicating flattened diaphragms and increased air spaces Asthma FRC measurements normal or above normal; MIP and MEP measurements normal or reduced; chest X-rays may indicate increased air spaces and congested or restricted airways; characterized by an improvement in all lung values after use of bronchodilators Chronic Bronchitis High FRC values often exceeding 100% of predicted; normal or reduced MIP and MEP values; chest X-rays show easily visible congestion Restrictive Lung Disorders: Neuromuscular Disease FRC values are normal; MIP and MEP are both significantly reduced; characterized by FVC values showing marked improvement in a sitting position as opposed to lying down Obesity Normal FRC; reduced MIP; MEP may also be reduced; chest X-rays reveal clear air passages but reduced thoracic space due to increased mass in the abdomen and thorax Asbestosis Normal or reduced FRC; lower than normal MIP and MEP; chest X-rays indicate irregular densities in the lower lung area 4

Activity Materials: All materials listed require one per group unless otherwise noted. PART 1: Lung Volume Bag (available from various science supply companies); disposable spirometer; wet spirometer (can be homemade or obtained from a science supply company); or spirometric probeware (available through Vernier ) Disposable mouthpieces one per student Nose clips one per student (May be purchased from Morgan Scientific http://www.morgansci.com/accessories/acctransflow.html or other supply stores) #3 or 4 rubber stopper; one hole Ace bandage Calculator Thermometer (for measuring room temperature) Stopwatch (for measuring FEV1) Metric measuring tape attached to wall (for measuring height in cm) or Stadiometer Measurement of Standing Height instruction page BTPS conversion table Predicted Normal Values Tables You Take My Breath Away Lung Disease Decision Tree Lab procedures and record sheet one per student PART 2: Set of You Take My Breath Away Patient Cards Predicted Normal Values tables (one per student) Calculator (one per student) You Take My Breath Away Lung Disease Decision Tree You Take My Breath Away Obstructive Lung Disease Decision Tree and Restrictive Lung Disease Decision Tree You Take My Breath Away Lung Disease Descriptions Reference materials, including dictionaries, encyclopedias, computer software, approved Internet sites, etc. Vis-à-vis markers (if cards are laminated) PART 3: Materials for this section of the activity will vary depending on the presentation medium chosen (brochure, poster, PowerPoint presentation, etc.) Guidelines and Scoring Rubric for You Take My Breath Away presentation (one per student) Reference materials and approved websites for disease research; suggestions include the National Heart, Lung and Blood Institute (www.nhlbi.nih.gov) and the American Lung Association (www.lungusa.org) 5

Activity Management Suggestions: Modifications: Be sure to identify those students with asthma or other respiratory problems. They should not participate in this activity because it involves repeated maximal inhalations and exhalations which could leave the students short of breath or, possibly, trigger an asthmatic episode. If lung volume bags are used, the volumetric markings on the bags will need to be extended below 1L (the smallest increment on most bags). Refer to the You Really Are Full of Hot Air! activity for details and photos describing how to make these markings. Alternatives to lung volume bags: Disposable spirometers or a homemade wet spirometer or Vernier offers a spirometer that collects data using the LabPro system and LoggerPro software Presentation topics may be limited to the six diseases included in Part 2 or you may wish to develop a more extensive list so that no two diseases are repeated in one class. Scoring of presentations can be accomplished using the suggested rubric provided, a rubric modified for your individual purposes, or a student developed rubric. Extensions: Part 2 and/or Part 3 of the activity can be used as extensions if time limitations do not permit completion of the entire project Post-activity extension Career Focus: invite a lung specialist or practicing respiratory therapist to speak to the class or take a field trip to a respiratory care facility (see Career of the Month; The Science Teacher; National Science Teachers Association; January, 2006) Activity References Used: 1. Cahill, M.; Exec. Dir. (1983). Pathophysiology Made Incredibly Easy. Springhouse: Springhouse Corp. 2. Hicks, G. H. (2000). Cardiopulmonary Anatomy and Physiology. Philadelphia: W.B. Saunders Co. 3. Johns, D. P. & Pierce, R. (2003) Pocket Guide to Spirometry. San Francisco: McGraw Hill. 4. Polgar, G. & Promadhat, V.(1971). Pulmonary Function Testing in Children: Techniques and Standards. Philadelphia: WB Saunders. 5. Ruppel, G. L. (1998) Manual of Pulmonary Function Testing (7th ed). St. Louis: Mosby: A Harcourt Health Sciences Co. 6. Quanjer, P. H., et. al. (2006) Become an Expert in Spirometry. Retrieved June, 2006. Web site: www.spirxpert.com. 7. Activity 1 Build Your Own Spirometer (n.d.), retrieved January, 2006 from Texas A&M University Department of Education. Web site: http://peer.tamu.edu/curriculum_modules/ OrganSystems/module_4/activity1.htm 6