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Explore the latest advancements in bioinstrumentation for precise measurement in healthcare settings. Learn about sensors, core body temperature measurement, blood pressure monitoring, oxygen saturation assessment, and blood glucose analysis.
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BIO307- Bioengineering principles SPRING 2019 Lecture 8 Bioinstrumentation(Chapter 11) Lecturer: Jasmin Sutkovic 6.5.2019
Introduction • Hospital operating rooms, emergency rooms, and doctors’ offices each contain an array of instruments used to measure and record a patient’s vital signs such as temperature, blood pressure, pulse, and oxygen saturation! • The medical device industry—the constellation of large and small companies that design, manufacture, and sell medical devices and instruments—is one of the largest and most rapidly growing sectors of the U.S. economy.
Next generation instruments • Makes the procedures quicker ! • More efficient ! • Lab on chip devices ?! • Microarray analysis chip
Overview of measurement systems • Most instrumentation systems contain common elements, which are present regardless of the parameter being measured! • INPUT and OUTPUT • The part of the instrument that detects the input is called a sensor. • The sensor converts the input parameter into a signal, usually an electrical voltage, whichvaries in a predictable and reliable way with changes in the input parameter
Measurement of body temperature • High body temperature one of the first indicators for abnormal conditions. • The normal body temperature is 98.6◦F (or 37◦C), although normal temperature varies somewhat from person to person. • Usually, a temperature above 99.5◦F (or 37.5◦C) is a sign of an underlying illness or infection (or a child who needs to stay home from school) • Hyperthermia, or elevated body temperature, can also occur as a result of prolonged exercise or exposure to excessive heat.
Temperature units 0° C = 273,15 K 0° C = 32F 0 °F = -17.77778 °C T(°C) = (T(°F) - 32) × 5/9
Core body temperature • Actual core body temperature can be measured directly by using catheters to place temperature sensors into deep body compartments, such as the pulmonary artery. • Placement of a catheter—a long, thin tube made of a biocompatible, flexible material, usually some kind of plastic—is accomplished by a procedure called a catheterization
Catheterization • By this procedure, the tip of the catheter can be precisely placed in the heart, or into the lumen of vessels near the heart! • This measurement is the most accurate reflection of the core body temperature. However, catheterization is invasive, expensive, and risky. • Therefore, other methods, such as the glass thermometer, are used for routine temperature measurements.
Usage of Mercury glass thermometer • However, their use in medicine is becoming increasingly rare. • Mercury is highly toxic to the nervous system, and many countries ban their use in medical applications; manufacturers have replaced mercury with liquid alloys of gallium, indium, and galinstan
Measurement of blood pressure • Blood pressure is critically important in the operation of the cardiovascular system and human health. • A patient with chronic high blood pressure (called hypertension) increases his or her risk of cardiovascular disease: Hypertension is a risk factor for atherosclerosis, heart attack, and congestive heart failure.
High blood pressure may be caused by small blood vessels in the brain . • The small blood vessels in the kidney are also affected by high blood pressure. • Alternately, blood pressure can become too low (a condition called hypotension) because of rapid blood loss after trauma or hypothermia.
120/80 • In an average adult, the systolic/diastolic blood pressure is 120/80 mmHg. • Individuals who are diagnosed with hypertension typically have blood pressure of 140/90 mmHg or higher.
How to measure? • The most common method of measuring blood pressure is based on the detection of Korotkoff sounds, also known as the auscultatorymethod!
Measurement of oxygen saturation in the blood • Proper blood O2 and CO2 levels are critical for maintenance of pH and healthy function of cells. • Lung diseases including asthma, emphysema, severe pneumonia, and pulmonary edema (fluid in the lungs) can cause low oxygen levels in the blood, a condition known as hypoxemia.
The pulse oximeteralso monitors the heart rate, or pulse; in fact, measurement of the pulsations of blood in the tissue is essential for its operation. The oximeter device, which consists of a light emitter probe coupled with a photodiode, is attached to a fingertip or earlobe (or leg of a neonate)
Measurement of blood glucose • In each test strip, there is an enzyme called glucose oxidase. This enzyme reacts with the glucose, in the blood sample and creates an acid called gluconic acid.The gluconic acid then reacts, with another chemical in the testing strip called ferricyanide. The ferricyanide and the gluconic acid, then combine to create ferrocyanide.Once ferrocyanide has been created, the device runs an electronic current through the blood sample on the strip.
Measurement of cardiac electrical potential by ECG • Some tissues in the body produce electrical potentials, such as the action potential of neurons and cardiac muscle cells, that are intimately related to their normal function. • Measurement of electrical potentials that arise from these tissues can, therefore, be important indicators of tissue function. The ECG (or EKG) provides a non-invasive, reliable method for screening and preliminary diagnosis of heart disease.
Animation for ECG and Heart beat • https://www.youtube.com/watch?v=v3b-YhZmQu8
Instruments in the research laboratory • Many biomedical engineers work in research laboratories, designing and testing new medical technologies, or applying engineering methods to understand human physiology.
Measurement of pH • Measurements of pH are performed almost daily in a biomedical research laboratory. • For example, pH control is essential for the solutions used for cell culture and for many other fluids prepared and used in the laboratory. • The buffer are usually in the range of 5-8.
The pH sensor is a potentiometric sensor: A voltage is generated without a current flow . The Ion sensing electrode (ISE) is a glass membrane tip that is permeable to H+ ions. When exposed to a solution of unknown pH, the ISE produces a voltage.
Spectrophotometry • A spectrophotometer is an instrument for measuring the intensity of light. • Most instruments are designed to allow for the measurement of the extent of light transmission through a biological sample, often fluid that is contained in a transparent cuvette
How does in work ? • https://www.youtube.com/watch?v=pxC6F7bK8CU
Biosensors • A biosensor is an analytical device that uses a biological sensing element—such as a protein, cell, or section of tissue—that is coupled with a physical or chemical transducer. • Biosensors are used to detect the presence of specific agents, which might be chemical groups, DNA, or other biochemical compounds.
