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.

Question 7: A surgeon reports that the electrosurgical unit (ESU) is not cutting effectively despite being set to the usual power level. The return electrode pad is properly applied. What should you check?

• The room temperature setting
• The active electrode tip for damage, carbon buildup, or improper connection (Correct answer)
• The anesthesia machine settings
• The operating table height

Correct answer: The active electrode tip for damage, carbon buildup, or improper connection

Reduced ESU cutting effectiveness typically indicates carbon buildup on the electrode tip, a damaged tip, or a poor connection.

Carbon buildup (eschar) insulates the tip, reducing current density. Test the ESU output with an RF power analyzer. If output matches the set value but clinical performance is poor, the issue is at the active electrode.

Question 8: A laboratory centrifuge is producing excessive vibration during operation. What is the most likely cause and what safety risk does this present?

• The centrifuge needs lubrication only
• Imbalanced sample loading or worn rotor bearings, which risks rotor failure and projectile release (Correct answer)
• The power supply voltage is too high
• The display panel is malfunctioning

Correct answer: Imbalanced sample loading or worn rotor bearings, which risks rotor failure and projectile release

Excessive vibration results from imbalanced samples or worn bearings, creating a serious risk of catastrophic rotor failure.

Check sample balance, inspect the rotor for cracks or deformation, inspect bearings, and verify the centrifuge is level. Safety features include imbalance detectors and reinforced lids.

Question 9: A syringe pump alarm indicates 'occlusion' repeatedly, but the IV line appears patent and free of kinks. What should be investigated?

• The pump needs a firmware update
• The syringe barrel may be binding, the plunger driver mechanism may be worn, or a downstream stopcock may be partially closed (Correct answer)
• The pump needs to be replaced
• The patient needs to be repositioned

Correct answer: The syringe barrel may be binding, the plunger driver mechanism may be worn, or a downstream stopcock may be partially closed

False occlusion alarms suggest excessive mechanical resistance from a binding plunger, worn mechanism, or partially closed stopcock.

Check all downstream stopcocks, verify the correct syringe brand is selected in pump settings, check for crystallization, and test with a water-filled syringe to isolate pump vs. line issues.

Question 10: After a power outage, several patient monitors fail to automatically reconnect to the central monitoring station. The network infrastructure has been verified as operational. What is the most likely issue?

• The monitors need replacement
• The monitors lost their network configuration during the power interruption and need IP settings restored or DHCP leases renewed (Correct answer)
• The central station software license expired
• The monitors' display panels are damaged

Correct answer: The monitors lost their network configuration during the power interruption and need IP settings restored or DHCP leases renewed

After a power outage, monitors may fail to reconnect due to DHCP lease expiration or boot sequence timing issues.

Check each monitor's network status for valid IP, restart monitors one at a time for fresh DHCP requests, and consider DHCP reservations to prevent recurrence.

Question 11: A patient reports receiving a mild tingling sensation when touching the bed rail while connected to a patient monitor. No alarm has triggered. What is the appropriate immediate action?

• Tell the patient it is normal static electricity
• Immediately disconnect the patient from the monitor, remove the device from service, and perform electrical safety testing (Correct answer)
• Increase the monitor alarm volume
• Apply hand lotion to the patient's skin

Correct answer: Immediately disconnect the patient from the monitor, remove the device from service, and perform electrical safety testing

A tingling sensation indicates stray electrical current flowing through the patient, which is a potentially dangerous leakage current situation.

The sensation threshold is approximately 1 milliamp; the cardiac fibrillation threshold via intracardiac path is only 10 microamps. This may constitute a reportable event under FDA MDR requirements.

Question 12: A blood gas analyzer is producing results that fail quality control. The QC material is within its expiration date and has been stored properly. What systematic troubleshooting approach should be taken?

• Run patient samples anyway and note the QC failure
• Try a new QC lot, recalibrate the analyzer, check reagents and electrode condition, and contact manufacturer support if needed (Correct answer)
• Turn the analyzer off and back on
• Replace the entire analyzer

Correct answer: Try a new QC lot, recalibrate the analyzer, check reagents and electrode condition, and contact manufacturer support if needed

Systematic troubleshooting involves trying a new QC lot, performing calibration, checking reagents, and inspecting electrode condition.

No patient results should be reported until QC passes. Lock out the analyzer per laboratory SOP and redirect samples to a backup analyzer. Inspect electrode membranes for damage, bubbles, or protein buildup.

Question 13: A ventilator's tidal volume display reads 500 mL but a calibrated test lung measurement shows only 420 mL. What is the most likely cause?

• Flow sensor calibration drift (Correct answer)
• Incorrect PEEP setting
• Low oxygen supply pressure
• Faulty inspiratory valve

Correct answer: Flow sensor calibration drift

Flow sensor drift is the most common cause of tidal volume display inaccuracy when the set and delivered volumes differ consistently.

Question 14: A nurse reports that a patient's SpO2 monitor reads 98% while the patient appears cyanotic. Which troubleshooting step should be performed first?

• Check probe placement and peripheral perfusion (Correct answer)
• Replace the entire monitor
• Recalibrate the SpO2 module
• Measure ABG immediately and discard the monitor reading

Correct answer: Check probe placement and peripheral perfusion

Poor perfusion or improper probe placement are the most common causes of falsely high SpO2 readings before escalating to hardware replacement.

Question 15: An infusion pump alarms 'upstream occlusion' but the tubing appears clear. What should the BMET check next?

• Closed roller clamp or kinked tubing upstream of the pump (Correct answer)
• Battery level of the pump
• Software version of the pump firmware
• IV bag height relative to the patient

Correct answer: Closed roller clamp or kinked tubing upstream of the pump

A closed clamp or subtle kink upstream of the pump head is the most frequent cause of upstream occlusion alarms when visible tubing appears unobstructed.

Question 16: During a preventive maintenance inspection, an electrosurgical unit's leakage current measures 450 µA chassis to ground. What action is required?

• Remove from service; leakage exceeds the 300 µA limit for ESUs (Correct answer)
• Return to service; the reading is within acceptable limits
• Install an additional ground wire and retest
• Report to nursing and continue normal use

Correct answer: Remove from service; leakage exceeds the 300 µA limit for ESUs

NFPA 99 and AAMI ES60601-1 limit chassis leakage current to 300 µA for patient-care equipment; 450 µA requires the unit be taken out of service.

Question 17: A defibrillator delivers only 150 J when set to 200 J during an output verification test. After replacing the energy storage capacitor the problem persists. What should be investigated next?

• Charging circuit and charge relay (Correct answer)
• Patient cable integrity
• Battery voltage under load
• Front-panel display calibration

Correct answer: Charging circuit and charge relay

If the capacitor is confirmed good, the charging circuit or charge relay is the next most likely cause of low delivered energy.

Question 18: A hospital bed's weight scale consistently reads 5 kg below the known weight of a calibration mass. Which corrective action is most appropriate?

• Perform a span calibration adjustment using NIST-traceable weights (Correct answer)
• Replace the load cell immediately
• Zero the scale with the patient in bed
• Add a correction factor to nursing documentation

Correct answer: Perform a span calibration adjustment using NIST-traceable weights

A consistent offset (span error) is corrected through span calibration using traceable reference weights, not by replacing hardware first.

Question 19: A patient monitor's ECG trace shows excessive 60 Hz artifact despite proper lead placement. After checking lead connections, what is the next troubleshooting step?

• Verify patient ground electrode contact and integrity (Correct answer)
• Replace the ECG module
• Switch the monitor to a different electrical outlet
• Increase the filter bandwidth setting

Correct answer: Verify patient ground electrode contact and integrity

Poor or absent ground (RL/right-leg drive) electrode contact is the most common cause of persistent 60 Hz powerline interference on ECG.