Transcript 5 - KUET
Presented byMd. Bashir Uddin Roll: 1215502 Dept. of BME KUET, Khulna-9203 Medical devices or instruments which are used to facilitate patient care, as well as biomedical research are known as medical instrument. Devices such as pacemakers, ultrasound machines, EKGs and blood pressure devices are just a few of the devices that are used in the biomedical field. A branch of biomedical engineering that deals with the knowledge of medical instruments and their application to the medical field is known as medical instrumentation. Generally medical instruments can be grouped in two broad heads: a) Diagnostic b) Therapeutic These are further subdivided into two or more sub groups: (i) Basic and Sophisticated, (ii) (ii) Mechanical, Electro-Mechanical & Electronic Measuring Instrument - Blood Pressure Instrument Recording Instrument – ECG Machine Monitoring Instrument – Heart Rate Monitoring Imaging Instrument – MRI Machine Therapeutic Instrument – ICU Ventilator Instrument ECG Machine It has capacity to monitor multi parameters of a patient Examples: NIBP, IBP, Heart Rate, Body Temperature. ECG Tracing Normal and abnormal condition of patient Alarm facilities for monitoring parameters Alarm ensured physician and nurse attention Bed side patient monitor Medical Ultra sound Imaging Instrument MRI Instrument An ICU Ventilator instrument Is used for those patients who are unable to take breath normally Picture of ICU Ventilator An instrumentation (or instrumentational) amplifier is a type of differential amplifier that has been outfitted with input buffers, Which eliminate the need for input impedance matching Thus make the amplifier particularly suitable for use in measurement and test equipment. Amplifier used in medical field is called medical instrumentation amplifier. Characteristics of medical instrumentation amplifier A type of differential amplifier No need of impedance matching Outfitted with input buffers Very low DC offset Low drift Low noise Very high open-loop gain Very high common-mode rejection ratio Very high input impedances. An instrumentation amplifier Preamplifier A preamplifier (preamp) is an electronic amplifier that prepares a small electrical signal for further amplification or processing. A preamplifier is often placed close to the sensor to reduce the effects of noise and interference. It is used to boost the signal strength to drive the cable to the main instrument without significantly degrading the signal-to-noise ratio (SNR). The noise performance of a preamplifier is critical. Wide range of input sensitivities Covered virtually all signal sources Calibrated zero suppression to expanded desired portion of an input Rejects noise or unwanted signal components by using low pass filtering Capacity neutralization Current injection Low leakage current Low dc drift suitable for intracellular measurements through high resistance fluid-filled electrodes Differential amplifiers Ac coupled amplifiers Carrier amplifiers DC amplifiers Chopper input dc amplifiers Chopper stabilized dc amplifiers DC bridge amplifiers Isolation Amplifiers Particularly suitable for use in measurement and test equipment. Instrumentation amplifiers are used where great accuracy and stability of the circuit both short- and long-term are required.