CONTENTS
Part 1 Basics
1 A Perspective on Medical Instrumentation = 3
1.1 Definition of a Medical Instrument = 3
1.2 Historical Considerations = 5
The Invention of the Thermometer = 6
The Stethoscope and Hearing Enhancement = 6
Sight Enhancement = 7
Chemical Instrumentation and the Senses = 9
Twentieth-Century Developments = 10
1.3 The Role of Electronic Circuit Theory = 19
a.c. Circuits = 21
Voltage Division = 28
Current Division = 29
Gain Function Analysis = 30
BJT Equivalent Circuit = 32
References = 34
Exercises = 34
2 The Origin of Biopotentials, Electrocardiograms, and Electrical Shock = 37
2.1 Fundamental Laws for Current in Biological Tissue = 37
Fick's Law = 39
Particle Drift = 40
Single-Cell Membrane Potential = 40
Resting Potential in a Cell = 42
Action Potential and Muscle Contraction = 44
2.2 Biopotentials in the Heart = 45
2.3 The Electrocardiogram = 46
2.4 Electrical Shock = 49
High-Frequency Effects = 53
Microshock and Macroshock = 55
References = 56
Exercises = 56
3 Hospital Equipment Safety and Organization, and a Logical Approach to Troubleshooting = 59
3.1 Electrical Hazards of Medical Instruments = 59
Macroshock Hazards = 62
Microshock Hazards = 64
3.2 Devices to Protect Against Electrical Hazards = 68
Ground Fault Interrupter = 68
Isolation Transformer = 69
Line Isolation Monitor = 70
Receptacle Tester = 70
Electrical Safety Analyzer Equipment = 72
3.3 An Equipment Safety Program = 72
Hospital Regulations = 73
Inspections of Equipment = 74
Emergency Power Systems = 75
Oxygen Safety = 77
Safety in the Operating Room = 77
Hazards of Gases = 79
Pressure Chambers = 81
3.4 Preventive Maintenance = 82
3.5 A Logicai Approach to Troubleshooting = 83
References = 86
Exercises = 87
4 Medical Instrument Transducers and Component-Level Troubleshooting = 89
4.1 Electrode Transducers = 89
The Surface Electrode = 90
Half-Cell Potential and Equivalent Circuit Elements = 94
4.2 Thermal Transducers = 100
4.3 The Wheatstone Bridge = 107
Sensitivity of a Wheatstone Bridge = 111
4.4 Strain Gauges = 113
The Strain Gauge in a Wheatstone Bridge = 118
Sensitivity of a Strain Gauge = 120
4.5 The Differential Capacitive Transducer = 121
4.6 Inductive Transducers = 126
4.7 Troubleshooting at the Component Level = 127
References = 128
Exercises = 129
5 Biopotential Amplifiers = 135
5.1 A Transistor Differential Amplifier = 137
Inverting and Noninverting Amplifiers = 140
5.2 Operational Amplifier Analysis = 143
Operational Amplifier Voltage and Current Sources = 147
Operational Amplifiers in Tandem = 149
High-Input-Impedance Amplifiers with Controlled Gain = 152
Differential Amplifier with Controlled Gain = 154
Buffer Amplifier for a Diff Amp = 157
5.3 Biopotential Measurement Interference = 158
Common-Mode Rejection in a Diff Amp = 161
5.4 Troubleshooting Medical Instrumentation Amplifiers = 163
References = 164
Exercises = 165
Part II Patient-Care Equipment
6 The Electrocardiograph and Unit-Level Troubleshooting = 177
6.1 TheECG = 177
The ECG Block Diagram = 180
6.2 ECG Lead Connections = 185
Augmented ECG Lead Connections = 190
Chest Lead Connection = 191
6.3 Common-Mode Voltage Reduction = 198
6.4 Push-Pull Power Amplifiers = 201
Maximum Power Transfer = 206
A Push-Pull Amplifier with Crossover Compensation = 209
Power Amplifier with Offset Control = 210
6.5 Power Supplies = 211
Power Supply Regulation = 214
6.6 Unit-Level Troubleshooting: ECGs = 215
Circuit-Board Swapping = 216
References = 217
Exercises = 217
7 The Electroencephalograph and Fiftering = 223
7.1 The EEG = 223
EEC Electrodes = 223
An EEC Block Diagram = 227
Electroencephalograms = 230
EEGs in Diagnosis = 231
7.2 Filters = 233
First-Order Filters = 236
Higher-Order Active Filters = 240
Second-Order Low-Pass Filters = 241
Second-Order High-Pass Filters = 244
Third-Order Low-Pass Filters = 247
Band-Reject Filters = 251
7.3 Troubleshooting an EEG = 254
References = 255
Exercises = 255
8 The Defibrillator and Step Response = 261
8.1 The Defibrillator = 261
Example Defibrillators = 264
8.2 Defibrillator Energy Delivery = 267
8.3 Analysis of the Defibrillator Voltage Waveform = 270
The Lown Voltage Waveform of a Defibriiiator = 271
Case I (Underdamped) = 273
Case II (Overdamped) = 275
8.4 Troubleshooting Defibrillators = 277
References = 278
Exercises = 278
9 The Pacemaker - A Digital Pulse Oscillator = 283
9.1 Properties of the Pacemaker = 284
Pacemaker Batteries = 286
Illustrative Pacemaker Characteristics = 288
9.2 Programmable Pacemakers = 291
9.3 Digital Pulse Oscillators = 294
A Comparator Circuit = 294
A Threshold Detector Analysis = 297
Square-Wave Generator = 299
Monostable Multivibrator = 304
Positive-Edge Triggered Multivibrator = 306
An Illustrative Pacemaker Circuit = 307
References = 309
Exercises = 310
10 Electrosurgical Units and Laser Surgery = 313
10.1 The Basic ESU = 313
Active Electrodes = 315
The Active Electrode Resistance = 316
The Return Electrode = 318
A Block Diagram = 321
10.2 Sinusoidal Oscillators = 323
10.3 An ESU Power Amplifier = 327
10.4 Troubleshooting an ESU = 330
10.5 Laser Surgical Devices = 333
The C$$O_2$$ Laser = 333
The Argon Laser Surgical Unit = 335
The Nd:YAG Laser = 336
References = 337
Exercises = 337
11 Catheters and Blood Pressure Monitoring = 341
11.1 Circulation System Measurements = 341
Pumping Action of the Heart = 341
Arterial Pressure Measurement = 344
Invasive Blood Pressure Measurement = 346
Fluid Resistance = 347
Instrumentation for Direct Pressure Measurement = 348
Pressure Transducer Calibration = 349
Pressure Measurements in the Heart = 351
11.2 Catheter Measurements = 355
The Equivalent Circuit of a Catheter = 356
Fluid Inertance = 356
Compliance = 357
The Fluid-Electrical Analogy = 358
The Catheter Equivalent Circuit = 359
The Physical Formulas for Catheter Components = 359
Frequency Response of a Catheter with a Diagram = 360
Tuning a Catheter = 363
Pinches, Bubbles, and Leaks in a Catheter = 363
References = 368
Exercises = 368
12 Respiratory Equipment and Pulmonary Function Monitoring = 371
12.1 Therapeutic and Diagnostic Equipment = 371
12.2 The Ventilator = 374
Ventilator Modes of Operation = 374
12.3 A Spirometer = 381
12.4 Pneumotachograph Airflow Measurement = 383
The Integrator Circuit = 385
Pneumotachograph Volume Measurements = 386
12.5 The Plethysmograph = 389
Measurement of Total Lung Capacity = 390
12.6 Troubleshooting Pneumatic Equipment = 392
References = 393
Exercises = 393
13 The Central Station Monitor, Microprocessor-Based Equipment, and System-Level Troubleshooting = 395
13.1 Machine Language = 396
13.2 Microprocessor Block Diagram = 398
The CPU = 399
The Memory Chip = 402
Input／Output Units = 403
13.3 A Microprocessor-Based Monitor = 405
Central Station Monitoring = 410
Troubleshooting Microprocessor-Based Equipment = 413
Self-Test = 415
A Logical Approach to Troubleshooting = 416
References = 417
Exercises = 417
Part III Specialized Medical Equipment
14 Clinical Laboratory Equipment = 423
14.1 Chemical Electrodes = 423
The pH Electrode = 424
14.2 A Blood Gas Analyzer = 425
The The $$^pCO_2$$ Electrode = 426
The The $$^pO_2$$ Electrode = 427
Noninvasive Blood Gas Monitoring = 429
14.3 Photometers and Colorimeters = 431
Diffraction Gratings = 431
Flame Photometers = 433
14.4 Blood Cell Counter = 437
Optical Methods of Cell Counting = 442
References = 443
Exercises = 443
15 Medical X-Ray Equipment = 445
15.1 X-Rays = 445
The X-Ray Tube = 446
The Nature of x-Rays = 449
X-Ray Absorption = 452
Tissue Contrast = 455
15.2 X-Ray Equipment Block Diagram = 456
The X-Ray Tube = 458
The Collimator = 461
The Bucky Grid = 463
The X-Ray Detector = 463
The Power Supply = 464
15.3 Fluoroscopic System = 467
15.4 X-Ray CT Scanners = 469
15.5 Nuclear Medicine Imaging = 473
Radioisotopes and Radiopharmaceuticals = 474
Radiation Detectors = 474
The Photomuitiplier Tube = 478
Gamma-Ray Camera = 478
15.6 Radiation Dose = 481
References = 487
Exercises = 487
16 Ultrasonic Equipment = 489
16.1 Therapeutic and Diagnostic Equipment = 489
Therapeutic Ultrasonic Equipment = 489
Piezoelectric Transducers = 491
Ultrasonic Imaging Equipment = 491
The Display Unit = 493
Scanning-Type Displays = 493
16.2 Ultrasonic Waves = 496
Wave Reflections = 500
Analysis of a Typical Ultrasonic Reflection = 503
Ultrasonic Power = 504
Attenuation in Ultrasonic Waves = 505
16.3 Ultrasonic Blood Flow Equipment = 506
An Analysis of the Doppler Effect = 506
An Analysis of Transit Time = 509
References = 510
Exercises = 510
Appendix A Computer Programs = 515
Appendix B Laplace Transforms = 526
B.I The Laplace Method = 526
The Step Source = 526
Laplace Equivalent Impedances = 527
Circuit Analysis of Laplace Equivalent Elements = 529
Laplace Transform Tables = 531
RC Circuit Step Response = 532
Appendix C Medical Terminology = 537
C.1 Common Prefixes = 537
C.2 Common Suffixes = 538
C.3 The Terminology of General Anatomy = 539
C.4 Terminology of Circulation = 541
C.5 Terminology of Respiration = 542
C.6 Terminology of the Nervous System = 542
C.7 Terminology of Sensory Organs = 543
Index = 545
