Pulmonary Function Indices in Critical Care Patients

ISBN-13: 9783540184324 / Angielski / Miękka / 1988 / 171 str.

Josef X. Brunner; Gunther Wolff

Opis

Respiration is a unique topic among various subdisciplines of physiology. Physiolo gists and clinicians are now able to communicate quantitative functional properties of lung mechanics and gas exchange in the language of the engineer, physicist and mathematician. This is largely due to intensive and stimulating work during the last decades of brilliant minds in a handful of excellent schools in the international family of physiologists. Among these founders of respiratory physiology are a number of clinicians, and they have. taken significant, part both in shaping the theoretical knowledge to clinical applicability and developing technical devices for diagnosis and therapy in pulmonology. However, the theory behind the evaluation of measure ments, and their interpretation in terms of clinical function tests, is so confusingly complex that the ordinary physician, not specifically trained in respiratory physiol ogy, finds himself unable to critically apply these techniques. We, therefore, need descriptions of respiratory physiology and of its clinical application presented in the language of the clinician. And that is what this book is meant to be. Written by an expert in electrical and biomedical engineering, and by an expert in intensive care medicine, this text constitutes an "operational manual" of clinical respiratory physiology. It does not intend to be another textbook of basic respiratory physiology or pathophysiology. This book not only addresses practical clinicians, particularly those of intensive care medicine, by describing the essentials of clinically relevant respiratory knowledge."

Spis treści

1. Evaluation of Pulmonary Function in the Intensive Care Patient.- 1.1. The Clinically Important Pulmonary Function Index.- 1.1.1. Evaluation and Monitoring of Circulatory Functions.- 1.1.2. Evaluation and Monitoring of Pulmonary Functions.- 1.1.3. “Simple” Measured Values.- 1.1.4. Physiological Models of Pulmonary Function Indices.- 1.1.5. The Clinically Important Pulmonary Function Indices.- 1.2. What Clinicians Expect of Transducers and Data Processing.- 1.2.1. The Chain of Instruments: Data Flow.- 1.2.2. Measuring Head and Measuring Instruments.- 1.2.3. Data Processing.- 1.2.4. Result-output.- 1.3. A Measuring System for Clinical Research.- 1.3.1. Obtaining Primary Data from the Measurements at the Airway Opening.- 1.3.2. Transducers.- 1.3.3. Preprocessing and Storage of Data.- 1.3.4. The Selection of the Pulmonary Indices Presented.- 2. Derivation of the Pulmonary Function Indices.- 2.1. Introduction.- 2.2. Breathing Mechanics.- 2.2.1. The Patient-ventilator Unit.- 2.2.2. Mathematical Model.- 2.2.3. Determining Lung Compliance and Airway Resistance.- 2.2.3.a Pleural Pressure.- 2.2.3.b Approximation of the Pressure-flow-volume Curve.- 2.2.4. Influence of the Lung Mechanics on the Distribution of Ventilation.- 2.3. Lung Volume and Intrapulmonary Gas Mixing.- 2.3.1. Nitrogen Washout.- 2.3.2. Measurement of the Functional Residual Capacity (FRC).- 2.3.3. Gas Mixing in the Acinus: The Stationary Interface.- 2.3.4. Gas Mixing in the Lungs.- 2.3.5. Measurement of the Airway Dead Space (Series Dead Space).- 2.3.6. Washout Efficiency from the Washout Curve (Decay Curve).- 2.4. Transpulmonary Gas Transport: Exchange of O2 and CO2.- 2.4.1. Diffusion from and into the Pulmonary Capillary Blood.- 2.4.2. Dissociation of O2 and CO2 in the Blood.- 2.4.3. The “Riley” 3-compartment Model.- 2.4.4. Analysis of the CO2-diagram.- 2.4.4.a Series Dead Space and Alveolar Ventilation.- 2.4.4.b Alveolar Efficiency of CO2-elimination.- 2.4.4.c Slope of the Alveolar Plateau.- 3. Assessment of Pulmonary Function Indices.- 3.1. Sensors.- 3.1.1. Measuring Head.- 3.1.2. Flow Measurement.- 3.1.2.a Principle of Measurement.- 3.1.2.b Linearity.- 3.1.2.c Calibration.- 3.1.2.d Correction of Errors Caused by Viscosity Changes.- 3.1.2.e Bandwidth.- 3.1.3. Gas Analysis.- 3.1.3.a Measuring Principle.- 3.1.3.b Automatic Sensitivity Control.- 3.1.3.c Linearity and “Cracking Pattern”.- 3.1.3.d Calibration.- 3.1.3.e Transport Delay.- 3.1.3.f Response Time.- 3.1.4. Pressure Measurement.- 3.1.4.a Measuring Principle.- 3.1.4.b Linearity.- 3.1.4.c Bandwidth.- 3.1.5. STPD and BTPS Conditions.- 3.2. Data Processing.- 3.2.1. Hardware and Data Flow.- 3.2.2. Automatic Recognition of the Respiratory Phases.- 3.2.3. Software.- 3.3. Testing the Measuring System.- 3.3.1. Absolute Accuracy.- 3.3.1.a Physical Model of the Lung.- 3.3.l.b Accuracy of Dead Space Determination.- 3.3.1.c Accuracy of the APV Measurements.- 3.3. l.d Decay Curve of the Model Lung.- 3.3.2. Precision of the Indices on the Stable Patient in “Steady State”.- 3.3.3. Reproducibility of the Nitrogen Washout.- 3.4. Use of the Measuring System in the Intensive Care Unit.- 3.5. Sensitivity of the Indices in the Presence of Acute Pathological Changes in the Lungs: Case Studies.- 3.5.1. Hypovolemia Before and After Correction.- 3.5.1.a Results.- 3.5. l.b Comparison with Conventional Methods.- 3.5.2. Acute Bronchial Constriction Before and After Therapy.- 3.5.2.a Results.- 3.5.2.b Comparison with Conventional Indices.- 3.5.3. Transient Processes: Effects of Inflating the Balloon of a Pulmonary Arterial Swan-Ganz Catheter.- 3.5.3.a A Model for Pulmonary Embolism.- 3.5.3.b Measurements in the Patient.- 3.5.3.c Results.- 4. Application I: Standard Values Dring Mechanical Ventilation After Cardiac Surgery.- 4.1. Patients and Examination.- 4.2. The Ventilation.- 4.3. Breathing Mechanics.- 4.4. Accessible Pulmonary Volume.- 4.5. Washout Efficiency and Moment Analysis.- 4.6. CO2 Production and O2 Consumption.- 4.7. Conventional Indices for CO2 Exchange.- 4.8. Specific Indices for CO2 Exchange.- 4.9. Cardiac Output.- 4.10. Correlations.- 5. Application II: A Study on Optimizing Mechanical Ventilation.- 5.1. Problem.- 5.2. Studies by Other Authors.- 5.3. Hypotheses.- 5.4. Patients and Methods.- 5.4.1. Patients.- 5.4.2. Measurements.- 5.4.3. Presentation of the Results.- 5.5. Results and Discussion.- 5.5.1. Effects of Changing the Tidal Volume (VT).- 5.5.2. Effects of the Positive End-expiratory Pressure (PEEP).- 5.5.3. Effects of the Inspiratory Flow Rate (V?I).- 5.5.4. Effects of the End-inspiratory Pause (EIP).- 5.6. Summarizing Discussion and Conclusions.- 5.6.1. Non-quantifiable Observations.- 5.6.2. Optimizing Ventilation.- 5.6.3. Recruitment of Compensatory Mechanisms.- 6. Application III: A Study on Intermittent Mandatory Ventilation (IMV).- 6.1. Patients and Methods.- 6.1.1. Patients.- 6.1.2. Measurements.- 6.1.3. Presentation of Results.- 6.2. Results.- 6.3. Discussion.- 6.3.1. CPPV Compared with IMV.- 6.3.2. IMVMB Compared with IMVSB.- 6.3.3. IMV Compared with CPAP.- 7. Appendices.- 7.1. On the Morphology of the Lungs.- 7.2. Technical Principles of Mechanical Ventilation.- 7.3. Measuring the Pleural Pressure with an Esophageal Balloon.- 7.4. Transport Equation for Convection and Diffusion.- 7.5. Relationship Between Dead Space and V?A/Q? Scatter.- 7.6. Viscosity of Gas Mixture.- 7.7. Determination and Dependencies of the Delay Time Between Flow Sensor and Mass Spectrometer.- 7.8. List of Formulas.- 7.9. Result-Tables.- 7.9.1. Tables to Application I: Standard Values After Cardiac Surgery.- 7.9.2. Tables to Applications II: Effect of Ventilation Variables.- 7.9.3. Tables to Application III: Intermittent Mandatory Ventilation.- References.