Biomedical test equipment is the set of instruments with which hospital engineers check that medical machines work correctly and safely. The engineers who do this are called biomedical engineers, and they work in the hospital's biomedical department. The equipment includes electrical safety analysers, patient simulators, defibrillator analysers, infusion pump analysers and radiation meters.
A medical machine can go wrong without showing it. A monitor can show a heart rate that is slightly wrong. An infusion pump can feed medicine slightly too fast. A defibrillator, the machine that gives an electric shock to restart the heart, can deliver less energy than the doctor selected. An X-ray machine can give more radiation than it should. None of these faults is visible on the machine's own screen. So every machine is tested on a schedule, usually once or twice a year, and again after every repair. This is called preventive maintenance.
Each tester checks one thing against a known value. An electrical safety analyser measures how much electric current leaks from a machine's metal case, because even a small leak can harm a patient. A patient simulator produces a known signal, such as a heart rhythm of exactly 80 beats a minute, and the engineer checks that the patient monitor shows 80. An infusion pump analyser measures how much fluid a pump really delivers in a set time. A radiation meter measures the dose and the energy of an X-ray beam.
For instance, a biomedical engineer at a hospital in Guwahati does the yearly check of a defibrillator from the emergency department. She connects it to a defibrillator analyser, sets the machine to 200 joules and fires a shock into the analyser. The analyser measures 196 joules, which is within the allowed limit. She then tests an infusion pump set to deliver 100 ml an hour. The analyser measures 97 ml in one hour, which is also within the limit. Both results are saved in each machine's record, with the date and her name. A sticker on each machine shows the date of its next test.
Radiation checks also have a legal side in India. The Atomic Energy Regulatory Board (AERB) requires quality assurance tests of X-ray and CT machines, a hospital's medical imaging equipment, before it licenses them and at regular intervals after that. Accreditation inspectors also ask to see the record of every test.
Modern testers store their results digitally. They send them to the hospital's maintenance software, where each test is a work order that is closed with its results. A real-time location system helps the engineers find each machine when its test is due.