Section 9.2.6 PUFF/VM Project of pulmonary disease in terms of measured data, referral diagnosis, and- patient characteristics. The program must operate effectively over a wide range of pathological conditions with a broad clinical perspective about the possible complexity of the pathology. B. Medical Relevance and Collaboration Interpretation of standard pulmonary function tests involves attempting to identify the presence of obstructive airways disease (OAD: indicated by reduced flow rates during forced exhalation), restrictive Tung disease (RLD: indicated by reduced lung volumes), and alveolar-capillary diffusion defect (DD: indicated by reduced diffusivity of inhaled CO into the blood). Obstruction and restriction may exist concurrently, and the presence of one mediates the severity of the other. Obstruction of several types can exist. In the laboratory at the Pacific Medical Center (PMC), about 50 parameters are calculated from measurement of lung volumes, flow rates, and diffusion capacity. In addition to these measurements, the physician may also consider patient history and referral diagnosis in interpreting the test results and diagnosing the presence and severity of pulmonary disease. Currently PUFF contains a set of about 250 physiologically based interpretation "rules". Each rule is of the form "IF THEN ". Each rule relates physiological measurements or states to a conclusion about the physiological significance of the measurement or State. The interpretation system operates in a batch mode, accepting input data and printing a report for each patient. The report includes: (1) Interpretation of the physiological meaning of the test results, the limitation on the interpretation because of bad or missing data; the response to bronchodilators if used; and the consistency of the findings _ and referral diagnosis. (2) clinical findings, including the applicability of the use of bronchodilators, the consistency of multiple indications for airway obstruction, the relation between test results, patient characteristics and referral diagnosis. (3) Interpretation Summary, which consists of the diagnosis of presence and severity of abnormality of pulmonary function. C. Progress Summary Knowledge base: PUFF is implemented on the PDP-10 in a version of the MYCIN system which is designed to accept rules from new task domains. A typical rule is: Priviteged Communication 251 E. A. Feigenbaum PUFF/VM Project . Section 9.2.6 If (FVC>=80) and (FEV1/FVC