Free CBET Practice Test
The Certified Biomedical Equipment Technician examination, commonly known as the CBET exam, is one of the most respected assessments for prospective healthcare workers. Success on this examination requires consistent and diligent study for months in advance.
The CBET exam covers the following content areas: anatomy and physiology (about 13% of the exam); public safety in the health care facility (about 17%); fundamentals of electricity, electronics, and solid-state devices (about 17%); medical equipment function and operation (about 26%); and medical equipment problem solving (about 27%). Within each of these content areas, there are several subjects that must be studied thoroughly. For instance, the anatomy and physiology content area includes questions on body systems, organs, blood, and terminology. The questions in this section of the CBET exam generally relate closely to the precise information required to perform as a biomedical equipment technician.
In the public safety in the health care facility section, meanwhile, the questions center on the following areas: electrical, chemical, radiation hazards, biological, fire, and codes and standards. You will need to perform extensive research on the various and particular dangers relevant to practice as a biomedical equipment technician. As in the other areas of the examination, the questions have been tailored to the real issues confronting a practicing technician. The CBET exam was developed by the Association for the Advancement of Medical Instrumentation.
CBET Exam Medical Device Currents:
1. Advantages of biphasic waveform defibrillation over the Lown-type waveform that was used up until the late 1980s include which of the following?
a. The use of direct current, instead of alternating current
b. A reduction in the energy needed for successful defibrillation
c. Biphasic defibrillation allowed for the introduction of portable units
d. All of the above
2. An electrocardiograph is malfunctioning. The power LED and the LCD backlight both are on, but there is no LCD display. Which of the following might be the cause of these observations?
a. A problem in a cable connection to the ECG control board
b. A defective LCD
c. A defective ECG control board
d. All of the above
3. A suspected problem with the thermal head of an electrocardiograph might be checked by performing which of the following procedures?
a. Printing out the letters "H" and "X" repeatedly
b. Running the paper roll at 10, 12.5, 25, and 50 millimeters per second
c. Running a demonstration
d. All of the above
4. A flow cytometer is providing a weak fluorescence intensity. This could be due to which of the following problems?
a. Excess antibody has been trapped
b. Several populations of cells are present in the sample, instead of one
c. The primary antibody and the secondary antibody are not compatible
d. The sample is contaminated with bacteria
5. Regarding the upkeep of medical ventilators, which of the following statements is MOST accurate?
a. Biomedical equipment technicians are responsible only for the maintenance of the units
b. Biomedical equipment technicians are responsible mostly for tuning the various settings
c. Biomedical equipment technicians are responsible for tuning the various settings and for maintenance of the units
d. Both tuning of settings and maintenance are the responsibility of respiratory therapists
1. B: The defibrillation technique developed by Bernard Lown in the 1950s used a strongly damped sinusoidal wave with a duration of approximately 5 milliseconds. This was supplied by a bank of capacitors that were charged to approximately 1 kilovolt that could deliver 100 to 200 joules of energy, with the power supplied as direct current. This was a big improvement compared with earlier methods that had used alternating current and could be performed only internally, with paddles placed on the heart during surgery. The Lown method also allowed units to become a lot smaller as the technology advanced in increments, so that they could be portable and carried in ambulances. The main advantage of the biphasic waveform that replaced the Lown approach is that the energy needed for successful defibrillation was reduced sharply. This reduces the risk of damage to the myocardium and burns on the skin.
2. D: Since the power LED is on, the machine is getting electrical power. Since the LCD backlight is on, the LCD is getting power, but one of the cables connecting to the ECG control board could be loose. If not, then either the LCD itself, or the ECG control board could be the source of the problem, and thus would need to be replaced. Before coming to this conclusion, check whether there is any response at all when any switches are pressed. If there is no response at all when any switch is pressed, then the ECG control board is the source of the problem.
3. A: The thermal head of an electrocardiograph (ECG) can be tested by having the machine print basic patterns. These can be letters, such as "H" and "X," or diagonal lines. Running the paper roll at 10, 12.5, 25, and 50 millimeters per second is performed to test the motor, gears, and sensors. A demonstration is a dummy ECG that is generated by the machine. This is not actually a test, but it is performed for educational purposes, for instance, to show people the basic features of a normal ECG reading.
4. C: Flow cytometers are used to count tiny particles, such as cells and chromosomes. The particles are suspended in a stream of liquid and recognized by fluorescent tags that are attached to the particles through antibodies. To amplify the signal, two antibodies are used. The primary antibody recognizes antigens on the particles themselves. In the case of cells, such antigens are molecules displayed on the cell surface. The primary antibody is made by, or using information from, the immune system of any of several animals, including humans. While the area of the primary antibody that binds the antigen on the cell is very specific to that antigen, the opposite end of the antibody is common to other members of the species from which the antibody was made. The fluorescent dye is attached to secondary antibodies, which attach to the species-specific antigens on the primary antibodies. The primary antibodies made from a mouse, for instance, need to be labeled with secondary antibodies that are "antimouse." If the labeled secondary antibody in this case were "antihuman," it would attach poorly to the primary antibody, so the signal would be absent, or reduced. Excess antibody being trapped would cause unusually high fluorescence, not a weak signal, while bacterial contamination would cause a scattering effect, because bacteria tend to autofluoresce at low levels. More than one population of cells present in a sample would show up as such on readings.
5. A: In the case of most biomedical equipment, various specialists are responsible for the day-to-day operation of the equipment, while the biomedical technician is called to see that it works properly. In the case of ventilators, the various settings have a direct influence on the patient's comfort level, so adjusting these settings falls within the job description of the respiratory therapist. A ventilator is an example of a device that must be able to continue operating in the event of a power failure, which is to say a life-critical system. A biomedical technician is responsible for making sure that all backup systems are operating and that the various settings are calibrated.