Pulmonary Physiology and Pathophysiology An Integrated, Case-Based Approach Second Edition

Pulmonary Physiology and Pathophysiology An Integrated, Case-Based Approach Second EditionChapter 1 Normal Physiology: Exercise ................ ......... ..... ... 1 Oxygen Consumption o Respiratory Muscles o Airways o Diffusion across the Blood-Gas Barrier o Introduction to the Pulmonary Circulation o Cardiac Output o Carriage of Oxygen and Carbon Dioxide by the Blood o Blood-Tissue Gas Exchange Chapter 2 Normal Physiology: Hypoxia ............................... 15 Oxygen Cascade from Air to Tissues o Effects of Reduced Barometric Pressure o Alveolar Ventilation Equation o Alveolar Gas Equation o Hyperventilation o Acid-Base Changes, Including Respiratory and Metabolic o Control of Ventilation, Including Respiratory Center, Central and Peripheral Chemoreceptors, and Integrated Responses Chapter 3 Chronic Obstructive Pulmonary Disease .......... .3 1 Clinical Features of a Typical Case o Pulmonary Function Tests o Pathology ofCOPD o Lung Volumes o Pressure-Volume Curve of Lung o Regional Differences of Ventilation o Forced Expiration o Dynamic Compression of Airways o VentilationPerfusion Inequality o Pathogenesis ofCOPD Chapter 4 Asthma ....... ....... ...................................................... 53 Clinical Features of a Typical Case o Pathology of the Airways o Gas Exchange o Airflow in the Lung o Convection and Diffusion o Pressures during the Breathing Cycle o Factors Determining Airway Resistance o Uneven Ventilation o Pathogenesis of Asthma o Principles of Bronchoactive Drugs Chapter 5 Diffuse Interstitial Pulmonary Fibrosis .... ..... .... 67 Clinical Features of a Typical Case o Pathology o Structure of the Alveolar Wall o Reduced Lung Volumes and Compliance o Diffusion across the Blood-Gas Barrier o Diffusing Capacity for Carbon Monoxide o Reaction Rates with Hemoglobin Chapter 6 Pulmonary Embolism .......................... ...... ........... 79 Clinical Featum of a Typical Case o Pathogenesis o Physiology of the Pulmonary Circulation o Pulmonary Vascular Resistance o Distribution of Blood Flow o Active Control of the Circulation o Metabolic Functiom of the Ci1,cztlation o Surface Temion and Su?factant Chapter 7 Pulmonary Edema ............... .................................. 94 Clinical Features of a Typical Case o Pathophysiology of Pulmonary Edema o Starling Equilibrium o Causes of Pulmonary Edema o Hypoxemia Caused by Shunt o Measurement of Shunt by Oxygen Breathing Chapter 8 Coal Workers' Pneumoconiosis ........................ 1 05 Clinical Features of a Typical Case o Atmospheric Pollutants o Deposition of Aerosols in the Lung o Clearance of Deposited Particles o Other Pneumoconioses and Related Conditiom Chapter 9 Acute Respiratory Failure .................................. 1 16 Clinical Featum of a Typical Case o Pathophysiology of Respiratory F ailu1'e o Hypoxernia o Carbon Dioxide Retention o Acidosis o Diaph1·agm Fatigue o Types of Respiratory Failure o Adult Respiratmy Distress Syndrmne o Oxygen Therapy o Mechanical Ventilation Chapter 10 Other Diseases ......... ........................................... 1 34 Infectious Diseases of the Lung, Including Pneumonia, Tube?'culosis, and Pulmonary Involvement in AIDS o Bronchiectasis o Bronchial Carcin011Za o Cystic Fibrosis Appendix A Symbols, Units, Equations, and Normal Values .............................................. 1 39 Appendix B Answers to Questions ......................................... 142 Figure and Table Credits ................................... 14 3 Index ...................................................................... 145 FIGURE I C h apter 1 Normal Physiology: Exercise D In this chapter we meet Ann, a first-year medical student and competitive cyclist. She has a high maximal oxygen uptake, and we discuss the physiological processes that make this possible. These include pulmonary ventilation, diffusion of oxygen across the blood-gas barrier, pulmonary blood flow, carriage of oxygen by the blood, and diffusion of oxygen to the peripheral tissues. List of Topics Oxygen consumption; respiratory muscles; airways; diffusion across the blood-gas barrier; pulmonary circulation; cardiac output; transport of oxygen and carbon dioxide by the blood; blood-tissue gas exchange. 0 ABOUT ANN Meet Ann, aged 23 years, a first-year medical student and competitive cyclist. She is healthy in all respects and has never had a serious illness. In addition to being a strong student who majored in biology in college and received excellent grades, Ann is an outstanding athlete. She became interested in competitive cycling while in high school, and in college she successfully competed at the national level. Although she is now too busy to train at the required level for competition, she rides every day and keeps herself very fit. Ann had a medical examination before coming to medical school, and no abnormalities were found. At that time a chest radiograph was normal, and a blood test showed a hemoglobin concentration of 14 g · dl-1• Because of her interest in exercise, Ann volunteered for a measurement of maximal oxygen uptake (Vo2max) in the pulmonary function laboratory using a stationary bicycle (Vo2 means volume of oxygen per unit time). The bicycle ergometer allowed the work rate (or power) to be increased gradually while Ann was pedaling. The results of the study are shown in GURE 1-1A. First, Ann's oxygen consumption (Vo2) was measured while she was at rest (work rate of zero). This was done by measuring with a flowmeter the amount of air she exhaled and determining its concentrations of oxygen and carbon dioxide. Then Ann's work rate was gradually increased, and it can be seen that the Vo2 �as linearly related to work rate. Eventually the Yo2 flattened out at a value defined as the Vo2max. In Ann's case this was 3.5 1· min-1• Any increase in work rate above this level can only occur through anaerobic glycolysis, which does not utilize oxygen. Figure 1-1B shows additional measurements that were made during Ann's exercise test. The volume of expired gas per minute (total ventilation, v� increased linearly-with Vo7 up to a certain point and then increased more rapidly. If there is a clear inflection point, this is sometimes called the anaerobic threshold, although the term is somewhat controversial. The blood lactate concentration (La) often rises markedly above this point. Someone like Ann (who is very fit) can exercise to high work levels before producing much lactate, but less fit people develop increased blood lactate levels earlier. Figure 1-1B