CABT Clinical Procedures & Techniques 3 — Questions and Answers
Question 1: During electrosurgery, the patient return electrode (dispersive pad) should be placed to minimize which primary hazard?
- Electromagnetic interference with monitors
- Current concentration causing burns at the pad site (Correct answer)
- Signal attenuation reducing cutting efficiency
- Static charge buildup on the surgical drapes
Correct answer: Current concentration causing burns at the pad site
Improper placement or poor contact of the dispersive pad concentrates current, causing burns; it must have full, even skin contact over a large, well-perfused area.
Question 2: A defibrillator's energy output is measured during performance testing. For a 200 J selected energy, what delivered energy range is typically acceptable per IEC 60601-2-4?
- ±5 J
- ±15% or ±4 J (whichever is greater) (Correct answer)
- ±10% of selected energy
- Exactly 200 J ±1 J
Correct answer: ±15% or ±4 J (whichever is greater)
IEC 60601-2-4 allows defibrillator delivered energy to be within ±15% of the selected energy or ±4 J, whichever is greater.
Question 3: In bronchoscopy suite support, the MOST critical role of the biomedical technician regarding the light source is to verify:
- Color temperature matches patient skin tone
- Output intensity is within manufacturer's specified lumens
- Automatic shut-off timer is disabled for long procedures
- Fiber bundle is connected before powering on to prevent tissue ignition (Correct answer)
Correct answer: Fiber bundle is connected before powering on to prevent tissue ignition
High-intensity light sources can ignite drapes or cause burns if activated without the fiber optic bundle connected; this safety check is paramount.
Question 4: Which ventilator parameter directly controls the fraction of time spent in inspiration versus total breath cycle time?
- Tidal volume (Vt)
- Inspiratory:Expiratory ratio (I:E ratio) (Correct answer)
- Peak Inspiratory Pressure (PIP)
- PEEP level
Correct answer: Inspiratory:Expiratory ratio (I:E ratio)
The I:E ratio defines the proportion of the respiratory cycle devoted to inspiration versus expiration, directly affecting gas distribution and hemodynamics.
Question 5: A Holter monitor recording shows frequent artifact. The MOST common cause of motion artifact in ambulatory ECG monitoring is:
- Battery depletion mid-recording
- Loose or improperly prepped electrode-skin interface (Correct answer)
- Magnetic interference from the patient's environment
- Incorrect lead polarity assignment
Correct answer: Loose or improperly prepped electrode-skin interface
Poor skin preparation (oil, hair, moisture) and loose electrodes cause the majority of Holter motion artifacts by introducing impedance fluctuations.
Question 6: When performing routine safety testing on a patient-connected medical device, the maximum allowable patient leakage current under normal conditions (NC) for a Type CF device is:
- 10 µA (Correct answer)
- 50 µA
- 100 µA
- 500 µA
Correct answer: 10 µA
IEC 60601-1 specifies that Type CF devices (intended for direct cardiac application) have a maximum patient leakage current of 10 µA under normal conditions.
Question 7: During an arterial blood gas (ABG) sampling procedure, the sample is exposed to room air for 10 minutes before analysis. Which values will be MOST affected?
- pH and bicarbonate (HCO3−)
- PaO2 and PaCO2 (Correct answer)
- Sodium and potassium levels
- Hemoglobin and hematocrit
Correct answer: PaO2 and PaCO2
Air exposure allows CO2 to escape (lowering PaCO2) and O2 to enter (raising PaO2), making gas tensions the most critically affected parameters.
CABT Clinical Procedures & Techniques 3
During electrosurgery, the patient return electrode (dispersive pad) should be placed to minimize which primary hazard?