CBET Healthcare Technology Problem-Solving 2 — Questions and Answers
Question 1: A nurse reports that a pulse oximeter is consistently reading SpO2 values 5-8% lower than expected on multiple patients. What is the most likely cause?
- The device software needs updating
- The sensor is placed incorrectly or the sensor window is dirty/damaged (Correct answer)
- The room temperature is too cold
- The device battery is low
Correct answer: The sensor is placed incorrectly or the sensor window is dirty/damaged
A consistently low SpO2 reading across multiple patients typically indicates a sensor issue.
Troubleshooting: clean the sensor, verify proper placement, try a known-good sensor, check the cable for damage, and test with a SpO2 simulator.
Question 2: An infusion pump displays a 'door open' alarm even though the door is fully closed and latched. What troubleshooting approach should you take first?
- Replace the entire pump
- Inspect the door latch mechanism and door switch for mechanical wear or debris (Correct answer)
- Update the pump firmware
- Replace the IV tubing set
Correct answer: Inspect the door latch mechanism and door switch for mechanical wear or debris
A false 'door open' alarm indicates the door switch or latch mechanism is not properly activating when closed.
Check the door gasket/seal, examine the microswitch with a multimeter, inspect the switch actuator for wear, and check wiring. This is high-priority because it prevents medication delivery.
Question 3: During an electrical safety test, a patient monitor passes all leakage current tests under normal conditions but fails under single-fault (open ground) condition. What does this indicate?
- The device is safe to use as-is
- The device has adequate basic insulation but relies on the ground connection for safety - internal insulation may be degrading (Correct answer)
- The safety analyzer is malfunctioning
- The device needs a new power cord only
Correct answer: The device has adequate basic insulation but relies on the ground connection for safety - internal insulation may be degrading
Passing under normal conditions but failing under open ground indicates internal insulation degradation that the ground path currently compensates for.
The device should be removed from service for investigation. Possible causes include moisture intrusion, insulation breakdown from heat/age, or contamination on circuit boards. Simply replacing the power cord would NOT fix this.
Question 4: A ventilator's delivered tidal volume is consistently 15-20% lower than the set value. The circuit has been checked for leaks and none were found. What should you investigate next?
- The patient's lung compliance
- The flow sensor calibration and the expiratory valve function (Correct answer)
- The ventilator's display screen
- The oxygen blender only
Correct answer: The flow sensor calibration and the expiratory valve function
With no circuit leaks, a consistent under-delivery suggests flow sensor drift or expiratory valve malfunction.
Flow sensors drift over calibration intervals. An expiratory valve that does not fully close during inspiration allows gas to escape without showing as a traditional circuit leak. Use a calibrated test lung to verify.
Question 5: Multiple physiologic monitors on the same nursing unit are showing intermittent signal artifact on ECG waveforms. Patient leads and cables have been replaced. What environmental factor should be investigated?
- Room lighting level
- Electromagnetic interference from nearby equipment or construction (Correct answer)
- Humidity level
- Ambient sound level
Correct answer: Electromagnetic interference from nearby equipment or construction
Intermittent ECG artifact affecting multiple monitors suggests electromagnetic interference from a shared environmental source.
Check for construction activity, malfunctioning fluorescent ballasts, LED lighting drivers, or HVAC variable frequency drives. An EMI detector can identify the source frequency.
Question 6: A defibrillator delivers energy but the delivered energy is consistently 20% below the selected setting. After verifying with a defibrillator analyzer, what is the most probable cause?
- The analyzer needs calibration
- Degraded internal capacitor or relay contact oxidation in the energy delivery circuit (Correct answer)
- The paddles need cleaning
- The battery is at half charge
Correct answer: Degraded internal capacitor or relay contact oxidation in the energy delivery circuit
Consistently low energy delivery typically indicates degradation of the main energy storage capacitor or increased resistance in the delivery pathway.
Electrolytic capacitors degrade over time (5-10 year lifespan). Increased charge time also suggests capacitor aging. Capacitor replacement requires manufacturer-authorized repair and high-voltage safety procedures.
CBET Healthcare Technology Problem-Solving 2
A nurse reports that a pulse oximeter is consistently reading SpO2 values 5-8% lower than expected on multiple patients.
What is the most likely cause?