PULMONARY PHYSIOLOGY IN CLINICAL PRACTICE

The Essentials for

Patient Care and Evaluation

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Table of Contents

Introduction
Historical perspective	1
Chapter 1: Clinical Approach	7
Schema for diagnosis and management	7
History	9
Physical Examination	10
Chest x-ray examination	12
Spirometry	18
Arterial blood gas analysis	19
Sputnum examination	20
Other tests and procedures	20
Evaluation of dyspnea	21
Bedside vs. Laboratory	25
Summary	25
Review questions	26
Chapter 2: Structure and Function	27
Gas properties	27
The atmosphere	28
Gas laws	30
ATPS, BTPS, and STPD	31
Gases in solution	32
Breathing-an overview of gas exchange	33
Lung disease and the respiratory system	41
Summary	42
Review questions	42
Chapter 3: Lung Mechanics	43
Breathing-a mechanical function	43
Pressure, volume, and flow	44
Generation of airway pressures	44
Lung compliance	46
Airway resistance	48
Lung volumes and capacities	49
Functional residual capacity	50
Forced vital capacity	52
Flow-volume curves and loops	57
Determinants for expiratory airflow	60
Small airways disease and dynamic compliance	64
Clinical value of using spirometry	65
Mechanics and gas exchange-correlation?	71
Summary	73
Review questions	73
Chapter 4: Pco2 and Alveolar Ventilation	74
Ventilation-minute, alveolar, and dead space	74
Pco2-its relation to alveolar ventilation and carbon dioxide	75
production
Pco2 and the respiratory quotient	77
Hyperventilation and hypoventilation	78
Clinical importance of the Pco2 equation	79
Pco2 in the clinical setting	79
Physiologic basis for hypercapnia	80
Vd/Vt and the Bohr dead space equation	82
Dangers of hypercapnia	80
Paco2 and need for ventilatory assistance	84
Noninvasive measurement of Pco2	85
Paco2-its relationship to oxygenation and acid-base balance	86
Summary	87
Review questions	87
Chapter 5: Oxygen Transfer	88
Clinical questions	88
Lung oxygen transfer	88
Oxygen diffusion and diffusing capacity	90
Alveolar oxygen pressure	92
Arterial oxygen pressure	93
Alveolar-arterial oxygen pressure difference	93
Pao2/Pao2 and Pao2/Flo2	95
Causes of low Pao2	95
Nonrespiratory causes of low Pao2	96
Respiratory causes of low Pao2	98
Ventilation-perfusion imbalance	98
Shunts and venous admixture	103
How V/Q imbalance reduces Pao2 and increases Paco2	104
Low mixed venous oxygen-effect on Pao2	106
V/Q imbalance in patients-variable effect on oxygen and carbon	107
dioxide
Summary	110
Review questions	110
Chapter 6: Is the Patient Adequately Oxygenated?	112
Clinical assessment	112
Hypoxemia vs. Hypoxia	113
The oxygenation cycle	114
Sao2 and oxygen content	115
Shifts of oxygen dissociation curve and P50	116
Carbon monoxide	118
Carbon monoxide exposure and its effects	120
Methemoglobinemia and sulfhemoglobinemia	121
Causes of reduced Sao2	122
Oxygen delivery	123
Fick equation	123
Mixed venous oxygen saturation	124
Summary	127
Review Questions	127
Chapter 7: Acid-base Balance	129
Hydrogen ion homeostatis	129
Concept of pH	130
Buffer systems	130
Henderson-Hasselbalch equation	131
Does the patient have an acid-base disorder?	132
Calculated vs. Measured HCO3	132
Acid-base nomogram	132
Acidemia and alkalemia	134
Anion gap	137
Primary vs. Compensatory processes	137
Acid-base map	138
In vitro titration curve for carbon dioxide	139
Base excess	140
Acute vs. chronic respiratory disorders	140
Acute vs. chronic metabolic disorders	141
Mixed acid-base disorders	143
Clinical approach to acid-base diagnosis	144
Summary	144
Review questions	145
Chapter 8: Pulmonary Circulation	147
Pulmonary vs. systematic circulation	147
Pulmonary hypertension and right heart failure	149
Causes of pulmonary hypertension	150
Assessment of hemodynamic status	152
Swan-Ganz catheterization	153
Insertion of Swan-Ganz catheter-pressure tracings	156
Hemodynamic measurements and calculations	158
Pulmonary artery wedge pressure-measurement	161
Pulmonary artery wedge pressure-what does it represent?	165
Pitfalls and complications in hemodynamic monitoring	170
Hemodynamic monitoring in clinical practice	171
Summary	173
Review questions	174
Chapter 9: Oxygen Therapy	175
Oxygen as a drug	175
Terminology in oxygen therapy	179
When to institute oxygen therapy	179
Classification of oxygen therapy	180
Low-supplemental Flo2 therapy	180
High-supplemental Flo2 therapy	184
Potential harm from oxygen therapy	187
Positive airway pressure and oxygen therapy	187
Hyperbaric oxygen	187
Monitoring oxygen	187
Monitoring oxygen therapy-clinical signs and Pao2	188
Blood transfusion-effect on Pao2 and oxygen content	190
Artificial blood	190
Methods of home oxygen therapy	190
Indications for home oxygen therapy	193
Summary	194
Review questions	195
Chapter 10: Artificial Ventilation	197
Intubation and artificial ventilation	197
Indications for artificial ventilation	200
Mode of artificial ventilation and Flo2	201
Normal breathing vs. ventilator breathing	201
Controlled ventilation	202
Assist- control ventilation	202
Intermittent mandatory ventilation	204
Ventilator settings	206
Ventilator compliance	209
High-frequency ventilation	209
Positive end expiratory pressure	211
Continuous positive airway pressure	212
Complications of artificial ventilation	213
Ventilator weaning	215
Summary	217
Review questions	217
Chapter 11: Respiratory failure	219
Definition of respiratory failure	219
Physiologic classification of respiratory failure	220
Clinical classification of respiratory failure	221
Acute vs. chronic respiratory failure	221
Pulmonary edema	221
Shunt equation	223
Adult respiratory distress syndrome	225
Physiological manifestations of ARDS	227
Management of ARDS	228
A case of oxygenation respiratory failure	229
Respiratory failure in chronic obstructive pulmonary disease	233
A case of combined ventilatory and oxygenation failure in COPD	234
Summary	237
Review questions	237
Chapter 12: Exercise Physiology	239
Exercise physiology	239
What happens during exercise?	239
Metabolism during exercise-aerobic vs. anaerobic	240
Paco2 during exercise	241
The exercise test	242
Physiologic changes during exercise	244
Normal exercise parameters	249
Clinical use of physiological exercise testing	249
Clinical interpretation of physiologic exercise testing	250
Summary	254
Review questions	254
Chapter 13: Pleural Effusions	256
Pleural fluid dynamics	261
Transudates vs. exudates	262
Diagnostic procedures	264
Determining cause of exudative effusion	266
Selected pleural fluid laboratory tests	268
Mechanism of pleural fluid acidosis	270
Use of laboratory tests in specific exudative effusions	271
Pneumothorax	275
Chest tube drainage	276
Obliteration of the pleural space	279
Pleural effusion, lung mechanics, and gas exchange	280
Summary	281
Review questions	281
Chapter 14: Sleep Disorders	283
The study of sleep disorders	283
Polysomnography	284
Normal sleep	286
Sleep apnea	289
Obstructive sleep apnea	292
Pickwickian syndrome	294
Ondine's curse	295
Cheyne-Stokes breathing	298
Summary	299
Review questions	300
Chapter 15: Newborn and infant	301
Changes at birth	301
Apgar score	304
The pediatric history	305
Vital signs	306
Physical examination	309
Chest x-ray examination	312
Pulmonary function tests	313
Blood gases	314
Ventilation-perfusion imbalance	317
Oxygen therapy	317
Hemodynamic assessment	318
Sudden infant death syndrome	319
Infant respiratory distress syndrome	320
Summary	322
Review questions	323
Appendix
A Answers to clinical problems	325
B Normal values for FVC and FEV1	357
C Basic equations and formulas	360
D Abbreviations and symbols	362
E Glossary	364
F Common clinical conditions	372
G General references	382
H Microcomputer programs	384