CABT Installation, Maintenance & Troubleshooting 3 — Questions and Answers
Question 1: When troubleshooting an ECG machine that produces a wandering baseline, the most likely cause is:
- Broken internal oscillator
- Poor electrode-to-skin contact or patient movement (Correct answer)
- Incorrect paper speed setting
- Failed analog-to-digital converter
Correct answer: Poor electrode-to-skin contact or patient movement
Wandering baseline on an ECG is most commonly caused by poor electrode contact, dry gel, patient movement, or respiration artifact.
Question 2: What does the term 'macroshock' refer to in the context of biomedical safety?
- A small current applied directly to the heart
- A larger current applied externally to the body surface sufficient to cause fibrillation (Correct answer)
- Static electricity discharge from equipment
- High-voltage discharge during defibrillation
Correct answer: A larger current applied externally to the body surface sufficient to cause fibrillation
Macroshock refers to a significant electrical current entering the body through external skin contact, requiring much higher current levels than microshock to cause ventricular fibrillation.
Question 3: A pulse oximeter is reading SpO2 values of 85% on a patient who appears clinically well-oxygenated. Which factor is least likely to cause this discrepancy?
- Nail polish on the finger
- Poor peripheral perfusion
- Ambient light interference
- Patient's respiratory rate (Correct answer)
Correct answer: Patient's respiratory rate
Respiratory rate does not directly affect SpO2 readings; nail polish, poor perfusion, and ambient light are all known causes of inaccurate pulse oximeter readings.
Question 4: During installation, the biomedical technician should ensure that an electrically powered medical device is connected to:
- Any available standard outlet in the room
- A hospital-grade grounded outlet meeting applicable standards (Correct answer)
- A GFCI outlet if available
- An ungrounded outlet to prevent ground loops
Correct answer: A hospital-grade grounded outlet meeting applicable standards
Medical devices must be connected to hospital-grade grounded outlets that meet NFPA 99 and UL standards to ensure patient and staff safety.
Question 5: After replacing a fuse in a biomedical device, the new fuse blows immediately upon power-up. The technician should:
- Install a higher-rated fuse to handle the load
- Investigate for a short circuit or overload condition before replacing the fuse again (Correct answer)
- Replace the fuse again and monitor for recurrence
- Use a wire jumper temporarily until parts arrive
Correct answer: Investigate for a short circuit or overload condition before replacing the fuse again
An immediately blown replacement fuse indicates an underlying short circuit or overload condition that must be diagnosed and corrected before installing another fuse.
Question 6: What is the correct procedure when disposing of a mercury-containing sphygmomanometer that is no longer in service?
- Place it in regular medical waste
- Follow facility hazardous waste protocols for mercury disposal (Correct answer)
- Disassemble it and discard components separately
- Return it to the manufacturer without any special precautions
Correct answer: Follow facility hazardous waste protocols for mercury disposal
Mercury is a hazardous material subject to EPA regulations; it must be disposed of through the facility's hazardous waste management program.
Question 7: A surgical electrosurgical unit (ESU) causes burns at the dispersive electrode site. Which is the most likely cause?
- Excessive generator output setting
- Inadequate contact area or poor adhesion of the dispersive electrode (Correct answer)
- Incorrect frequency setting
- Broken active electrode pencil
Correct answer: Inadequate contact area or poor adhesion of the dispersive electrode
Burns at the dispersive (return) electrode site are most commonly caused by inadequate skin contact area or poor adhesion, increasing current density at that site.
CABT Installation, Maintenance & Troubleshooting 3
When troubleshooting an ECG machine that produces a wandering baseline, the most likely cause is: