CABT Biomedical Equipment Technology & Function 4 — Questions and Answers
Question 1: Which sterilization method is most appropriate for heat-sensitive, moisture-sensitive endoscopes that cannot withstand steam autoclave cycles?
- Steam autoclave at 134°C
- Ethylene oxide (EtO) gas sterilization (Correct answer)
- Dry heat oven at 160°C
- UV light chamber
Correct answer: Ethylene oxide (EtO) gas sterilization
EtO gas penetrates packaging and device lumens at low temperatures, making it suitable for heat- and moisture-sensitive items like flexible endoscopes.
Question 2: In an ECG, a prolonged PR interval (>200 ms) indicates a conduction delay in which structure?
- Bundle of His
- Atrioventricular (AV) node (Correct answer)
- Sinoatrial (SA) node
- Purkinje fibers
Correct answer: Atrioventricular (AV) node
The PR interval represents the time from atrial depolarization to ventricular depolarization; prolongation indicates slowed conduction through the AV node (first-degree AV block).
Question 3: A centrifugal blood pump used in ECMO differs from a roller pump primarily because it:
- Requires a larger priming volume
- Is afterload-sensitive and cannot generate dangerously high pressures against an outlet obstruction (Correct answer)
- Cannot be used for cardiopulmonary bypass
- Delivers pulsatile rather than continuous flow
Correct answer: Is afterload-sensitive and cannot generate dangerously high pressures against an outlet obstruction
Centrifugal pumps are preload- and afterload-dependent; if the outlet is occluded, flow drops rather than pressure rising to dangerous levels, unlike roller pumps which can rupture the circuit.
Question 4: The 'over-damped' waveform on an arterial line pressure tracing is characterized by:
- Exaggerated systolic peaks and diastolic dips with ringing
- Blunted systolic peak and loss of the dicrotic notch (Correct answer)
- Absent waveform with flat baseline
- Increased pulse pressure with wide swings
Correct answer: Blunted systolic peak and loss of the dicrotic notch
Over-damping (from air bubbles, clots, or compliant tubing) absorbs energy and rounds the waveform, causing underestimation of systolic pressure and loss of fine features like the dicrotic notch.
Question 5: During a nuclear medicine gamma camera quality control test, a 'uniformity flood' is performed to check:
- Energy resolution of the photomultiplier tubes
- Homogeneous sensitivity response across the detector face (Correct answer)
- Spatial resolution of the collimator
- Count rate linearity at high activity levels
Correct answer: Homogeneous sensitivity response across the detector face
A uniformity flood test exposes the entire detector to a uniform source; non-uniform response (hot or cold spots) indicates PMT or crystal problems requiring service.
Question 6: A hospital-grade power strip differs from a consumer power strip primarily because it:
- Has a higher surge protection rating
- Has hospital-grade outlets with higher retention force and is listed for patient care areas (Correct answer)
- Includes a built-in UPS battery backup
- Provides isolated power equivalent to an OR panel
Correct answer: Has hospital-grade outlets with higher retention force and is listed for patient care areas
Hospital-grade power strips use high-retention outlets that resist accidental disconnection and meet UL 1363A standards for health care facilities, unlike consumer strips.
Question 7: A sequential compression device (SCD) used for DVT prophylaxis applies intermittent pneumatic compression to the legs. The primary physiological mechanism is:
- Increasing arterial inflow to warm the limb
- Augmenting venous return and stimulating endogenous fibrinolysis (Correct answer)
- Reducing lymphatic fluid accumulation
- Preventing arterial spasm in post-operative patients
Correct answer: Augmenting venous return and stimulating endogenous fibrinolysis
SCDs compress the leg veins in a distal-to-proximal sequence, enhancing venous return and triggering release of tissue plasminogen activator, reducing DVT risk.
CABT Biomedical Equipment Technology & Function 4
Which sterilization method is most appropriate for heat-sensitive, moisture-sensitive endoscopes that cannot withstand steam autoclave cycles?