Bioinstrumentation or biomedical instrumentation is an application of biomedical engineering which focuses on development of devices and mechanics used to measure, evaluate, and treat biological systems. The goal of biomedical instrumentation focuses on the use of multiple sensors to monitor physiological characteristics of a human or animal for diagnostic and disease treatment purposes. Such instrumentation originated as a necessity to constantly monitor vital signs of Astronauts during NASA's Mercury, Gemini, and Apollo missions.
Bioinstrumentation is a new and upcoming field, concentrating on treating diseases and bridging together the engineering and medical worlds. The majority of innovations within the field have occurred in the past 15–20 years, as of 2022. Bioinstrumentation has revolutionized the medical field, and has made treating patients much easier. The instruments/sensors produced by the bioinstrumentation field can convert signals found within the body into electrical signals that can be processed into some form of output. There are many subfields within bioinstrumentation, they include: biomedical options, creation of sensor, genetic testing, and drug delivery. Fields of engineering such as electrical engineering, biomedical engineering, and computer science, are the related sciences to bioinstrumentation.
Bioinstrumentation has since been incorporated into the everyday lives of many individuals, with sensor-augmented smartphones capable of measuring heart rate and oxygen saturation, and the widespread availability of fitness apps, with over 40,000 health tracking apps on iTunes alone. Wrist-worn fitness tracking devices have also gained popularity, with a suite of on-board sensors capable of measuring the user's biometrics, and relaying them to an app that logs and tracks information for improvements.
The model of a generalized instrumentation system necessitates only four parts: a measurand, a sensor, a signal processor, and an output display. More complicated instrumentation devices may also designate function for data storage and transmission, calibration, or control and feedback. However, at its core, an instrumentation systems converts energy or information from a physical property not otherwise perceivable, into an output display that users can easily interpret.
Common examples include:
Heart rate monitor Automated external defibrillator Blood oxygen monitor Electrocardiography Electroencephalography Pedometer Glucometer Sphygmomanometer The measurand can be classified as any physical property, quantity, or condition that a system might want to measure. There are many types of measurands including biopotential, pressure, flow, impedance, temperature and chemical concentrations. In electrical circuitry, the measurand can be the potential difference across a resistor. In Physics, a common measurand might be velocity. In the medical field, measurands vary from biopotentials and temperature to pressure and chemical concentrations. This is why instrumentation systems make up such a large portion of modern medical devices. They allow physicians up-to-date, accurate information on various bodily processes.
But the measurand is of no use without the correct sensor to recognize that energy and project it. The majority of measurements mentioned above are physical (forces, pressure, etc.), so the goal of a sensor is to take a physical input and create an electrical output. These sensors do not differ, greatly, in concept from sensors we use to track the weather, atmospheric pressure, pH, etc.
Normally, the signals collected by the sensor are too small or muddled by noise to make any sense of. Signal processing simply describes the overarching tools and methods utilized to amplify, filter, average, or convert that electrical signal into something meaningful.
Lastly, the output display shows the results of the measurement process. The display must be legible to human operator. Output displays can be visual, auditory, numerical, or graphical. They can take discrete measurements, or continuously monitor the measurand over a period of time.
Biomedical instrumentation however is not to be confused with medical devices. Medical devices are apparati used for diagnostics, treatment, or prevention of disease and injury. Most of the time these devices affect the structure or function of the body. The easiest way to tell the difference is that biomedical instruments measure, sense, and output data while medical devices do not.
Examples of medical devices:
IV tubing Catheters Prosthetics Oxygen masks Bandages
History Biomedical engineering and bioinstrumentation are new terms, but the practice behind them has existed for many generations. Since the beginning of mankind, humans have used what was available to them to treat the medical mishaps they encountered. Biomedical engineering was most developed in the nineteenth century. In the recent years, biomedical engineering has gained popularity and focused on creating solutions for issues in human physiology. Since then, inventions such as X-rays and stethoscopes have progressed and revolutionized the medical field.
The concept of biomedical engineering was developed after World War II and they even considered it as they make humans work easier as they give exact and Clear detailed reports.The invention of the first artificial heart valve was successfully implanted in 1952, the first artificial kidney was created in the 1940s, and a heart-lung machine was successfully used in a human heart surgery in 1953. These advancements are major milestones within the medical field as it provides life changing procedures. The development of the Positron Emission Tomography (PET) scan was a significant advancement within the biomedical field. the PET scan was invented by Edward Hoffman and Michael E. Phelps in 1974. the machine provides an effective imaging test for understanding the metabolic activity within the tissues and organs of the patient.
Space flight Bioinstrumentation was first developed in earnest by NASA during their early space missions, to gain a better understanding of how humans were affected by space travel. These early bioinstrumentation sensor arrays built by NASA constantly monitored astronauts ECG, respiration, and body temperature; and later measured blood pressure. This allowed physicians to monitor the astronauts vital-signs for potential problems. Data taken from Apollo 15 ECG bioinstrumentation showed periods of cardiac arrhythmia, which physicians and planners used to alter expected workload, diet, and the drugs in the on-board medical kits.
Development Instrumentation Devices A generalized structure for how medical devices should be developed follows from determining a clinical condition of a patient such as diabetes. Then the relevant physiological parameter to be measured would in this case be blood sugar concentrations, but for other situations could be blood pressure, heart rate, white blood cell count, or other signals and amounts in the body. Next, the method in which this physiological parameter is taken must be determined. For someone with type one diabetes, these could be a glucose monitoring system with a sensor placed just below the skin in the interstitial fluid that can measure the concentration of glucose. The next parameter that is chosen for the development of a biomedical instrumentation device would be the transducer design, which for this example would be changing glucose concentration to a measurable value such as voltage via the reaction from glucose and glucose oxidase's products with a reduction reaction causing a current to flow being transformed to a voltage change to be measured. The final step to the development of the device before signal digitization, processing, and display is filter and amplifier design which will clean up and increase the size of the physiological signal so that it is able to be detected and read out on the device.
Classes Medical devices are divided into three main classes. The first class is the lowest risk group and are medical devices that do not sustain life at all. These include for example bandages, wheelchairs, and tooth brushes. About thirty percent of medical devices fall under this category. Next, is class two with about sixty percent of all medical devices where the medical devices now include moderate risk. These include catheters, X-rays, and blood pressure cuffs. Finally, class three includes the medical devices with the most risk associated with its intended use. Only about ten percent of medical devices fall under this category since special parameters of safety must be shown to the FDA prior to its approval which is much more strict than the previous classes. Class three devices include pacemakers, cochlear implants, and heart valves. Overall, the FDA developed this system of medical devices classes in order to expedite the process of approval. When a medical device is organized into a lower class, and therefore a lower risk, it will be reviewed less stringent and be able to move into the medical field and market much quicker than devices that have high risk and must prove safety to risk benefits.
Classes of biomedical instruments include: Quantity Sensed: pressure, flow, temperature Transduction: resistance, induction, capacitance
Electrical Safety and Risk Classification Medical devices are also divided into different electrical safety and risk classifications:
Class 1 Class 2 Class 3 Type B applied part Type BF applied part Type CF applied part Defibrillation-proof type CF applied part Conformité Europeénne Class 1, class 2, and class 3 appliance classifications are defined by the IEC and are used to define how the device is protected against electric shock. Class 1 medical devices include all devices where protection from electric shock is achieved through wire insulation and a protected earth. Class 2 medical devices are classified by the presence of at least two layers of wire insulation - one basic layer insulation and a supplemental insulating layer or one layer of reinforced insulation. For example, cardiac monitors typically are IEC class 2 devices. Class 3 medical devices rely on limiting voltages to no higher than the SELV. This class of device does not require any protection from the input voltage for the user. SELV components must be insulated by two layers of protection from components operating about the SELV. Some examples of IEC class 3 devices are pacemakers and AEDs.
As the device class designation designates the method of electric protection, the type designation of the device denotes the degree of protection against electric shock. This is quantified by the maximum permitted leakage current from the device. Type designations are defined by the IEC 60601 standard. Type B applied parts have a maximum leakage current of 100μA and cannot be directly connected to the heart. Type BF applied parts have the same requirement for maximum leakage current, but differ in the fact that they are an isolated or floating device with conductive contact with the user. These would include a device such as a blood pressure monitor. Type CF applied parts have the most strict requirements and is used for devices that come in direct contact with the heart. The maximum leakage current is 10μA. An example of type CF applied parts is are dialysis machines.
Components The basic fundamental parts for any biomedical instrument are as following below:
Measurand: A physical quantity where the instrumentation systems would measure it. The human body would act as the source for measurand that would generate bio-signals. This would include the body surface or blood pressure in the heart.