Unit 4 biomedical
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The document discusses various instruments used for respiratory and blood measurements. It describes pneumographs which detect respiration through chest movements. Spirometers are used to measure lung volumes and capacities. Impedance pneumography monitors respiration rate using changes in chest impedance during breathing. Other topics covered include blood cell counting methods like Coulter and optical techniques, electromagnetic and ultrasonic blood flow meters, and measuring blood pH using glass electrodes in blood gas analyzers.
![Blood Flow Meter
• Blood flow is nothing but the volume of blood per time
[ml/min].
Typical values for blood flow [cm/s]:
1. Aorta 100 – 250
2. Abdominal 100
3. Vena Cava 5 – 40
69 DEEPAK.P](https://image.slidesharecdn.com/unit4biomedical-160822181636/85/Unit-4-biomedical-69-320.jpg)
Unit 4 biomedical
- 1. DEEPAK.P UNIT 5 Instrumentation for clinical laboratory 1
- 3. Respiration It is responsible for bringing oxygen in to the body and discharging waste particles from body. 3 DEEPAK.P
- 4. Respiratory System Measurements 1. Vital capacity 2. Functional residual capacity 3. Inspiratory capacity 4. Total Lung capacity 4 DEEPAK.P
- 5. Respiratory System Measurements Tidal volume = volume of air inhaled during normal quiet breathing. Residual volume (RV) = volume of air in the lungs after maximal expiration. Functional residual capacity (FRC) = volume of air in the lungs after exhalation during quiet breathing. Inspiratory capacity = volume of air from FRC to maximal inhalation. Vital lung capacity from RV to maximal inhalation. 5 DEEPAK.P
- 6. Respiratory System Measurements 1. Pneumograph is used to detect respiration. 2. Spiro meters are used for the following measurements. 1. Tidal Volume (TV) 2. Inspiratory Reserve Volume (IRV) 3. Expiratory reserve volume (ERV) 4. Residual Volume (RV) 5. Minute Volume 3. Pulmonary Capacities are also calculated by respiratory machine. 6 DEEPAK.P
- 8. Pneumograph A Pneumograph, also known as a pneumatograph or spirograph, is a device for recording velocity and force of chest movements during respiration. There are various kinds of pneumographic devices, which have different principles of operation. 1.In one mechanism, a flexible rubber vessel is attached to the chest and the vessel is equipped with sensors. 2.Others are impedance based. •In first case a very thin elastic tube filled with mercury is stretched across patient chest. 8 DEEPAK.P
- 9. Pneumograph Impedance pneumography is a commonly-used technique to monitor a person ’s respiration rate, or breathing rate. The idea behind the Impedance pneumograph is that, the AC impedance across the chest of a subject changes as respiration occurs. It is mainly used in neonatal respiration monitors. 9 DEEPAK.P
- 10. Pneumograph In second case it is implemented by either using two electrodes or Four electrodes The objective of this technique is to measure changes in the electrical Impedance of the person ’s thorax caused by respiration or breathing. 10 DEEPAK.P
- 12. Impedance Pneumograph Eqlt. Ckt. 12 DEEPAK.P
- 13. Pneumograph • There are two type of pneumograph that uses piezoresistive strain gauge transducers. 1. Mercury strainguage 2. Same wire foil or semiconductor piezoresistive devices. • Thermistors are used as flow detectors in some pneumographs. • In one type a bed thermistor is placed just inside the patients nostril. • In another type thermistors are mounted on a patient who is fitted with an endotracheal tube or is on a respirator or ventillator. 13 DEEPAK.P
- 14. Thermistor airway Pneumograph 14 DEEPAK.P
- 15. Pneumograph • In some transducer , the thermistor is placed with a thin platinum wire stretched taut across a short section of tubing. 15 DEEPAK.P
- 18. Spirometer • A bell or jar is suspended from top in a tank of water. • An air hose leads from a mouthpiece to the space inside of the bell above the water level. • The weight maintains the bell at atmospheric pressure. • When the patient exhales, the pressure inside the bell increases above atmospheric pressure causing the bell to rise. • Similarly, When the patient inhales, the pressure inside the bell decreases causing the bell to comes down. 18 DEEPAK.P
- 20. Bio Electric Amplifiers 20 DEEPAK.P
- 21. Amplitudes and spectral ranges of some important bio-signals 21 DEEPAK.P
- 23. Instrumentation Amplifier An instrumentation (or instrumentational) amplifier is a type of differential amplifier that has been outfitted with input buffer amplifiers. The input buffer eliminate the need for input impedance matching and thus make the amplifier particularly suitable for use in measurement and test equipment. The gain of the circuit is given by 23 DEEPAK.P
- 25. Instrumentation Amplifier The two amplifiers on the left are the buffers. The rightmost amplifier, along with the resistors is standard differential amplifier circuit. 25 DEEPAK.P
- 27. Isolation Amplifier Isolation amplifiers are a form of differential amplifier that allow measurement of small signals in the presence of a high common mode voltage by providing electrical isolation and an electrical safety barrier. They protect data acquisition components from common mode voltages, which are potential differences between instrument ground and signal ground. Isolation amplifiers are used in medical instruments to ensure isolation of a patient from power supply leakage current. Amplifiers with internal transformers eliminate external isolated power supply. 27 DEEPAK.P
- 29. Symbol of Isolation Amplifier 29 DEEPAK.P
- 35. Isolation Amplifier The 3650 and 3652 are optically coupled integrated circuit isolation amplifiers. Compared to these earlier isolation amplifiers, the 3650 and 3652 have the advantage of smaller size, lower cost, wider bandwidth and integrated circuit reliability. 35 DEEPAK.P
- 38. Chopper Stabilized amplifiers Chopper stabilization constantly corrects input offset voltage errors, including both errors in the initial input offset voltage and errors in input offset voltage due to time, temperature, and common-mode input voltage. A chopper-stabilized amplifier is actually two amplification paths in parallel. A high-accuracy, low-frequency path (A2) incorporates high gain and chopping, while high-frequency signals are amplified by the parallel wideband amplifier A1. The outputs of both stages are subtracted in a summer amplifier, whose output is fed back to the inputs of both amplifiers through a feedback resistor. 38 DEEPAK.P
- 39. Chopper Stabilized Amplifiers 39 DEEPAK.P
- 40. Chopper Stabilized amplifiers 40 DEEPAK.P
- 41. Chopper Stabilized amplifiers 41 DEEPAK.P
- 42. Chopper Stabilized amplifiers Two problems arise when we tries to record low level bio- potentials. Noise DC Drift These are worse , if we are using high gain amplifiers to amplify the weak bio-potentials. Noises produced in amplifier circuit and human body makes the problem worse. Drift is the change in gain or dc offset caused by thermal effects on amplifier components. 42 DEEPAK.P
- 43. Chopper Stabilized amplifiers Drift can be minimized with the use of negative feedback. This can be avoid by convert a DC (or near dc, low frequency analog) signal to an AC signal that will pass through the amplifier. The solution is to chop or sample the analog signal at a frequency that will pass through the AC coupled amplifier. 43 DEEPAK.P
- 45. Input Guarding Physiological signals are low amplitude signals. In most cases physiological signals accompanied by large CM signals. If Op Amps are used, both differential (E)and common mode (Ecm) signals are present. The op amp cannot distinguish artifact from real signal and C.M signal. To avoid these problem, input guarding is used. Here , we are placing a shield at the CM signals. Input cable is shielded to avoid CM signals. 45 DEEPAK.P
- 46. Input Guarding Technique for increase both the input impedance of the amplifier of bio-potentials and the CMRR. Instrumentation amplifier providing input guarding 46 DEEPAK.P Driven-right-leg circuit reducing common-mode interference.
- 49. Flow volume Transducer • It measures the flow volume in litres per minute. • The transducer assembly consists of differential pressure transducer and an airway containing a wire mesh obstruction. • The wire mesh produces a pressure drop when it placed in an airway. • This pressure drop is measured as a differential pressure across the mesh. 49 DEEPAK.P
- 50. Flow volume Transducer 50 DEEPAK.P
- 52. Blood Cell Counting 52 DEEPAK.P
- 53. Blood Cell Counting 53 DEEPAK.P
- 54. Blood Cell Counting 54 DEEPAK.P
- 55. Blood Cell Counting 55 DEEPAK.P
- 56. Blood Cell Counting 56 DEEPAK.P
- 57. Coulter Method: Blood Cell Counting 57 DEEPAK.P
- 58. Coulter Method: Blood Cell Counting 58 DEEPAK.P
- 59. Blood Cell Counting Using this technology, cells are sized and counted by detecting and measuring changes in electrical resistance when a particle passes through a small aperture. This is called the electrical impedance principle of counting cells. A blood sample is diluted in saline, a good conductor of electrical current, and the cells are pulled through an aperture by creating a vacuum. Electrical resistance or impedance occurs as the cells pass through the aperture causing a change in voltage. 59 DEEPAK.P
- 60. Blood Cell Counting This change in voltage generates a pulse . The number of pulses is proportional to the number of cells counted. The size of the voltage pulse is also directly proportional to the volume or size of the cell. This was the principal parameter used in earlier analyzers for characterizing all cell types, but it is now used primarily for counting and sizing red blood cells and platelets. 60 DEEPAK.P
- 61. Coulter Method: Blood Cell Counting 61 DEEPAK.P
- 62. Pico Cell Blood Cell Counting 62 DEEPAK.P
- 63. Pico Cell Blood Cell Counting 63 DEEPAK.P
- 64. Optical Blood Cell Counting 64 DEEPAK.P
- 65. Optical Blood Cell Counting 65 DEEPAK.P
- 66. Optical Blood Cell Counting 66 DEEPAK.P
- 68. Blood Flow Meter • Blood flow is the continuous circulation of blood in the cardiovascular system. • The science dedicated to describe the physics of blood flow is called hemodynamics. • Usually the blood flow measurements are more invasive than blood pressure measurements / ECG The abnormal changes in the blood flow or blood velocity gives rise to malformation of vessels. 68 DEEPAK.P
- 69. Blood Flow Meter • Blood flow is nothing but the volume of blood per time [ml/min]. Typical values for blood flow [cm/s]: 1. Aorta 100 – 250 2. Abdominal 100 3. Vena Cava 5 – 40 69 DEEPAK.P
- 70. DEEPAK.P70 EM Blood Flow Meter
- 71. EM Blood Flow Meter • The commonly used instrument for blood flow is Electromagnetic type. 71 DEEPAK.P
- 72. EM Blood Flow Meter • The operation principle behind the electromagnetic blood flow meters is Faraday’s law of electromagnetic induction which states that if electrical current carrying conductor moves at right angle through a magnetic field, an electromotive force is induced in the conductor. Electromagnetic blood flow meters can be classified in to 1. Sine wave electromagnetic blood flow meter 2. Square wave electromagnetic blood flow meters 72 DEEPAK.P
- 73. EM Blood Flow Meter • The sine wave electromagnetic blood flow meter uses wave alternating current to generate the required magnetic field. • The flow voltage (induced voltage) is also sinusoidal. • Even if for lower frequency application, the circuit becomes complex and high frequency application results a problem of stray capacitance effect, it can’t be used for a wide range of frequency values. • In the square wave electromagnetic blood flow meter, the excitation is square wave alternating current, and the induced voltage is square wave too. 73 DEEPAK.P
- 74. EM Blood Flow Meter 74 DEEPAK.P
- 75. EM Blood Flow Meter 75 DEEPAK.P
- 76. EM Blood Flow Meter 76 DEEPAK.P
- 77. Types of EM Blood Flow Meter 77 DEEPAK.P
- 78. EM Blood Flow Meter 78 DEEPAK.P
- 79. EM Blood Flow Meter 79 DEEPAK.P
- 80. DEEPAK.P80 Ultrasonic Blood Flow Meter
- 81. Ultrasonic Blood Flow Meter 81 DEEPAK.P
- 82. Ultrasonic Blood Flow Meter • An ultrasonic flow meter is a type of flow meter that measures the velocity of a fluid with ultrasound to calculate volume flow. • The blood cells in the fluid reflects the ultrasound signal with a shift in the ultrasonic frequency due to its movement. • Using ultrasonic transducers, the flow meter can measure the average velocity along the path of an emitted beam of ultrasound, by averaging the difference in measured transit time between the pulses of ultrasound propagating into and against the direction of the flow or by measuring the frequency shift from the Doppler effect. 82 DEEPAK.P
- 83. Ultrasonic Blood Flow Meter 83 DEEPAK.P
- 84. Ultrasonic Blood Flow Meter 84 DEEPAK.P
- 85. Ultrasonic Blood Flow Meter 85 DEEPAK.P
- 86. Ultrasonic Blood Flow Meter 86 DEEPAK.P
- 87. Ultrasonic Blood Flow Meter 87 DEEPAK.P
- 88. Ultrasonic Blood Flow Meter 88 DEEPAK.P
- 89. Ultrasonic Blood Flow Meter 89 DEEPAK.P
- 90. Ultrasonic Blood Flow Meter 90 DEEPAK.P
- 91. Ultrasonic Blood Flow Meter 91 DEEPAK.P
- 92. Doppler Blood Flow Meter 92 DEEPAK.P
- 94. Blood pH Measurement • In chemistry, pH is the negative log of the activity of the hydrogen ion in an aqueous solution. • Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. • Pure water has a pH of 7. • Mathematically, pH is the negative logarithm of the activity of the (solvated) hydronium ion, more often expressed as the measure of the hydronium ion concentration 94 DEEPAK.P
- 95. Blood pH Measurement • Blood pH is an important factor to determine the acid base balance in the human body. • Blood pH level plays an important role for your overall health, because if your blood pH level is acidic, your cells cannot function properly. • One of the major contributors to acidosis is carbon dioxide, a byproduct of metabolism. • Carbon dioxide combines with water to form carbonic acid. • The normal pH of blood is between 7.35-7.45. 95 DEEPAK.P
- 96. Blood pH Measurement •The increase in hydrogen ion concentration causes the pH of the body fluids to decrease. •If the pH of the body fluids falls below 7.35, symptoms of respiratory acidosis become apparent. •Blood gas analyzers are used to measure pH, pCO2 and pO2 etc •pH of biological fluids is measured using a glass electrode. 96 DEEPAK.P
- 97. Blood pH Measurement 97 DEEPAK.P
- 98. Blood pH Measurement 98 DEEPAK.P
- 99. Blood pH Measurement 99 DEEPAK.P
- 100. Blood pH Measurement •A blood sample for measuring pH parameters is collected in a glass syringe. •The blood pH level can be determined by 1.Saliva pH test 2.Urine pH test 3.Blood pH test 100 DEEPAK.P
- 101. Saliva Blood pH Test •Saliva pH test: It is one of the fastest and simplest tests for measuring blood pH level. •However, it is not the most accurate. •Before taking the test, you should wait at least two hours after eating. •Depending on the food you eat, it can increase or decrease your blood pH level. •To do the saliva pH test, go buy the pH paper test strip at your local drug stores and health food stores and follow the directions on the package. 101 DEEPAK.P
- 102. Urine Blood pH Test •This test works similar to the saliva pH test, but it tests urine instead of saliva. •The pH test strip for testing urine is the same as the saliva pH test strip. •Blood pH test •This test is not as convenient as the saliva and urine pH test, but it is usually more accurate. •To do the blood pH test, you will need to visit your doctor and get your blood drawn. 102 DEEPAK.P
- 103. Blood pH Measurement •One of the best ways to bring your blood pH back to its normal state is to eat mostly organic alkaline food. Another way is to drink distilled water. •Distilled water is very pure water, so if you want to reduce your risk of acidosis, you will need to add some minerals to it. 103 DEEPAK.P
- 104. Blood pH Measurement 104 DEEPAK.P
- 106. PH SENSITIVE FET 106 DEEPAK.P
- 107. Conductimetric PH Sensor 107 DEEPAK.P
- 108. Fiber Optic PH Sensor 108 DEEPAK.P
- 109. Fiber Optic PH Sensor 109 DEEPAK.P