This book is a description of the medical and technical disciplines that make up the new world of “medical electronics”. It should prove useful as a reference for medical and paramedical personnel. For the electronics engineer and technician, the book will serve as a bridge to the medical world they will serve. For the administrator, it will be an explanation of his “new department” and what it will be accomplishing.
1. INTRODUCTION 1.1 Electronics and Medicine 1.2 What is Medical Electronics? 1.3 What Medical Electronics is Not 1.4 Man’s Hierarchy of Organization 1.5 The Human Body as One System
2. HUMAN CELL-ACTION POTENTIALS 2.1 Cells and their Structure 2.2 Characteristics of Living Organisms 2.3 General Characteristics of a Human Cell 2.4 Resting Potential 2.4.1 Factors Affecting Ion Diffusion through Membranes 2.5 Nernst Equation 2.6 Electrical Characteristics of the Human Cell 2.7 Bioelectric Potentials-Origin 3. BASIS OF BIOELECTRIC POTENTIALS A) Cardiovascular System-Electrocardiogram (ECG) 3.1 Blood Circulation 3.2 The Heart and its Mechanical Activity 3.3 Measurement of Absolute Arterial Blood Pressure 3.3.1 Oscillometric Method 3.3.2 Doppler Technique 3.3.3 Finger Blood Pressure Gauge 3.4 Electrical Potentials Generated Within the Heart-origin of the ECG Waveform 3.5 Composition of the ECG B). The Central Nervous System (CNS)- Electroencephalogram (EEG) 3.6 Human Nerve Cell and Impulse Conduction. 3.7 The Nervous System 3.8 Anatomy of the Brain 3.9 Excitation and Inhibition Potentials vi Principles of Medical Electronics and Biomedical Instrumentation 3.10 The Electroencephalogram 3.11 Evoked Potentials C) Muscle Action and the Sensory System-Electromyogram (EMG) 3.12 The Motor Unit 3.13 Muscle Action 3.14 The Muscular Servomechanism 3.15 Potential Generated during Muscle Action-EMG 4. BIOPOTENTIAL ELECTRODES 4.1 The Electrode-Electrolyte Interface 4.2 Electrode Types 4.2.1 Surface Metal Plate Electrodes 4.2.2 Needle and Wire Electrodes 4.2.3 Microelectrodes 4.3 Stimulating Electrodes 5. TRANSDUCERS FOR BIOMEDICAL APPLICATIONS 5.1 Classification of Transducers 5.2 Selecting a Transducer 5.3 General Features of a Biomedical Instrumentation System 5.4 Variable Resistance Transducers 5.4.1 Resistive Track Transducers 5.4.2 Application of Resistive Potentiometers 5.4.3 Strain Gauge 5.4.4 Semiconductor Strain Gauges 5.4.5 Applications of Strain Gauge Transducers 5.5 Variable Inductance Transducers 5.5.1 Applications of L VDT 5.6 Variable Capacitance Transducers 5.6.1 Applications of Capacitive Transducers 5.7 Thermoresistive Transducers 5.7.1 Thermistor Linearization 5.8 Photoelectric Transducers 5.8.1 Photoemissive Tubes 5.8.2 Photovoltaic Cell 5.8.3 Photoconductive Cells 5.8.4 Application of Photoelectric Transducers 5.9 Piezoelectric Transducers 5.9.1 Applications of Piezoelectric Transducers
6. BIOMEDICAL AMPLIFIERS 6.1 Basic Requirements 6.2 Differential Amplifier. 6.3 Carrier Amplifier 6.4 Chopper Amplifier 6.5 Phase Sensitive Detector 7. PRINCIPLES OF RECORDERS FOR RECORDING BIOELECTRIC EVENTS 7.1 Characteristics of the Recording System 7.2 The Analog Graphic Recorders-Types 7.2.1 Moving Coil Recorder 7.2.2 Moving Iron Recorder 7.3 Analog Recording Techniques and Equipment 7.3.1 Heated Stylus 7.3.2 The Optical-light 7.3.3 The Ink-jet 8. ELECTROCARDIOGRAPHY 8.1 Electrocardiographic Planes 8.2 Frontal Plane ECG Measurements 8.3 Lead Systems for Recording ECG 8.3.1 Standard Bipolar Leads 8.3.2 Unipolar Leads 8.4 Determination of the Heart-Rate 8.5 Sagittal Plane ECG Measurements 8.6 Electrocardiograph 9. ELECTROENCEPHALOGRAPHY 9.1 Signal Sources 9.Q Input Electrodes 9.3 Placement of Electrodes 9.4 EEG Recording Modes 9.5 Electroencephalograph 9.6 Applications of the EEG viii Principles of Medical Electronics and Biomedical Instrumentation 10. ELECTROMYOGRAPHY 10.1 EMG Electrodes 10.1.1 Surface Electrodes 10.1.2 Needle Electrodes 10.2 The Electromyograph System 10.3 Determination of Conduction Velocities in Motor Nerves 10.4 Quantity of Electricity Associated with Muscle Contraction 10.5 Electroretinograph 10.6 Electroocculograph 10.7 Electrogastrograph 11. RESPIRA TION 11.1 Mechanism 11.2 Spirometer 11.3 Pneumotachography 12 SPECIAL TECHNIQUES FOR MEASUREMENTS OF NONELECTRICAL BIOLOGICAL PARAMETERS 12.1 Electrical Impedance Plethysmography 12.2.1 Audiometry 12.2.2 Anatomy of the Human Ear 12.2.3 Threshold of Hearing 12.2.4 Audiometer 12.2 Audiometry 12.3 Techniques to Aid Observation 12.3.1 Laryngostroboscope 12.3.2 X-rays and Radiography 12.3.3 X-ray Computed Tomography 12.3.4 Diagnostic Ultrasound 12.4 Electromagnetic Flowmeter 13 ELECTRONIC INSTRUMENTS FOR AFFECTING THE HUMAN BODY 13.1 Stimulators 13.1.1 Strength/Duration Curves 13.1.2 Types to Stimulators 13.1.3 An Electrodiagnosticffherapeutic Stimulator 13.1.4 Peripheral Nerve Stimulator 13.2 Defibrillators 13.2.1 Mechanism 13.2.2 AC Defibrillators 13.2.3 Capacitive Discharge DC Defibrillators 13.2.4 Delay-Line Capacitive Discharge DC Defibrillator 13.2.5 Square-Wave Defibrillator 13.2.6 Defibrillator Electrodes 13.2.7 Defibrillator Analyer 13.3 Pacemakers 13.3.1 Types of Pacemakers 13.3.2 Modes of Operation 13.4 Diathermy 13.4.1 Shortwave Diathermy 13.4.2 Microwave Diathermy 13.4.3 Ultrasonic Diathermy 13.4.4 Surgical Diathermy 13.5 Respirators 13.6 Blood Pumps 13.7 Myoelectric Control of Paralysed Muscles 14. BIOTELEMETRY 14.1 Physiological Parameters Adaptable to Biotelemetry 14.2 Elements of the Biotelemetry System 14.3 Principles of Design of the Biotelemetry System 14.4 Single Channel Radio Telemetry System 14.5 Transmission of ECG by Telemetry 14.6 Transmission of Blood Pressure by Telemetry 14.7 Telephone Links 15. PATIENT MONITORING AND INTENSIVE CARE SYSTEM 15.1 System Arrangement 15.2 Information Transmission System 15.3 Resuscitation Unit
16 PATIENT SAFETY AND ELECTROMEDICAL EQUIPMENT 16.1 Physiological Effects of Electrical Currents X Principles of Medical Electronics and Biomedical Instrumentation 16.2 Macroshock and Microshock 16.3 Preventive Measures to Reduce Shock Hazards 16.4 Maintaining Safe Patient Electrical Environment 16.5 Earth-free Patient Monitoring 16.6 Standards
17 COMPUTER APPLICATIONS IN MEDICINE 17.1 Hospital Administration 17.2 Clinical Tests 17.3 Laboratory Tests 17.4 Computer-assisted Medical Imaging 17.5 Computerised Aid to the Physically Handicapped 17.6 Medical Diagnosis and Decision Making 17.7 Patient Monitoring 17.8 Patient Management
18 THE HOSPITAL AND THE MEDICAL ELECTRONICS DEPARTMENT 18.1 Medical Responsibility 18.2 Using Equipment 18.3 Design of Electromedical Equipment 18.4 Technical Responsibility 18.4.1 Servicing Priorities and Conditions 18.4.2 Preventive Maintenance 18.5 Administrative Responsibility 18.6 Hospital Responsibilities 18.7 The Medical Electronics Department (MED) 18.7.1 One MED 18.7.2 The MED within the Engineering Department 18.8 Resident Technical Personnel 18.8.1 The Medical Electronics Technician 18.8.2 The Medical Electronics Engineer 18.8.3 The Technical Administrator 18.9 First and Last, the Patient
Bibliography Index