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What This Guide Helps With
CPR feedback is present but inaccurate because of sensor placement, patient support surface, movement, accessories, connection, or sensor damage.
Step-by-Step Troubleshooting
1. Protect the Patient and Do Not Interrupt Effective CPR
During an active resuscitation, do not delay or degrade chest compressions to troubleshoot questionable feedback values.
If CPR feedback appears unreliable, rescuers should continue resuscitation according to clinical protocol while the device issue is addressed later or another verified feedback system is used.
Expected outcome: Effective CPR continues without dependence on potentially inaccurate device feedback.
2. Confirm the Reported Feedback Problem
Determine whether the complaint involves:
- Compression depth
- Compression rate
- Both depth and rate
- Intermittent feedback
- Values that remain fixed
- Values that change without actual compressions
- Incorrect feedback only during transport
- Abnormal feedback on a specific bed, mattress, or support surface
If evaluating on the bench, use an appropriate training or test setup rather than a patient.
Expected outcome: The inaccurate parameter and operating conditions are clearly identified.
3. Inspect the CPR Sensor and Cable
Inspect the CPR sensor externally for:
- Cracks
- Damaged housing
- Loose cable entry
- Bent or contaminated connector contacts
- Pinched cable
- Severe cable kinks
- Evidence of impact or fluid intrusion
Check that the sensor connection is fully seated.
Expected outcome: The CPR sensor and connection are physically intact and securely connected.
If reseating the connector restores normal feedback and repeated testing remains stable, troubleshooting can stop after final verification.
4. Verify Sensor Placement
Confirm that the CPR sensor is positioned according to the approved clinical setup and is not shifted, tilted, or trapped under another item.
Incorrect placement can cause the device to detect compressions while calculating misleading depth or rate information.
Expected outcome: The sensor remains correctly positioned and mechanically stable during compressions.
If correcting sensor placement restores accurate and repeatable feedback, proceed to final verification.
5. Evaluate the Support Surface
Determine whether testing or clinical use occurred on:
- A soft mattress
- An air mattress
- A stretcher with significant movement
- A transport surface
- A surface that flexes during compressions
Movement of the support surface can affect compression feedback even when the sensor itself is functioning.
Use an appropriate firm test surface when evaluating the system off-patient.
Expected outcome: Feedback becomes stable and consistent when external surface movement is eliminated.
If the complaint is explained by the support surface and device performance is normal under controlled conditions, document the finding and troubleshooting can stop after verification.
6. Eliminate External Motion
During controlled testing, verify that the sensor is not being affected by:
- Stretcher movement
- Vehicle movement
- Bed articulation
- Equipment striking the sensor
- Rescuer hand movement unrelated to compressions
- Loose accessories contacting the sensor
Expected outcome: Feedback corresponds consistently with actual test compressions when external motion is minimized.
If eliminating movement restores correct readings, no internal repair is indicated.
7. Substitute a Known-Good CPR Sensor
If available and approved, connect a known-good compatible CPR sensor and repeat the same controlled test.
This isolates the reusable sensor/accessory from the Propaq MD itself.
Expected outcome: The known-good sensor provides stable and reasonable compression feedback under the same test conditions.
If the known-good sensor resolves the issue, remove the suspect sensor from service and replace it according to facility procedure.
8. Compare the Suspect Sensor on Another Compatible System
When available and permitted, test the suspect sensor on another compatible verified system.
Avoid changing multiple variables at once.
Expected outcome: The fault either follows the CPR sensor or remains with the original Propaq MD.
If the problem follows the sensor, the accessory should be removed from service. If the problem remains with the original device, escalate the Propaq MD for further evaluation.
9. Verify Rate and Depth Feedback Under Controlled Conditions
Using an appropriate simulator, manikin, or approved CPR testing method, verify that the displayed rate and depth feedback responds consistently as compressions are intentionally varied.
Do not invent acceptance tolerances. Use the manufacturer-approved verification method and test criteria available to Clinical Engineering.
Expected outcome: Feedback changes appropriately and consistently with controlled compression input and meets applicable approved test criteria.
If testing passes after correcting an external cause, troubleshooting can stop.
10. Perform Final Functional Verification
Confirm that:
- CPR sensor recognition is stable
- Sensor connection remains secure
- Rate feedback responds appropriately
- Depth feedback responds appropriately
- No intermittent loss occurs during movement of the cable
- Other essential defibrillator functions remain normal
Complete applicable return-to-service testing.
Expected outcome: CPR feedback operates reliably under controlled conditions and the original complaint is resolved.
If successful, return the equipment to service according to facility policy.
11. Escalate Persistent Inaccurate Feedback
If feedback remains incorrect with correct placement, controlled surface conditions, secure connections, and a known-good CPR sensor, remove the unit from service.
A sensor being detected does not prove that the feedback measurement chain is accurate.
Expected outcome: A potentially misleading CPR feedback system is prevented from returning to clinical use until properly evaluated.
If the Problem Persists
Common external causes such as sensor placement, support-surface movement, cable condition, connection problems, and defective accessories have been ruled out.
The remaining issue may involve sensor electronics, internal signal processing, configuration, or other service-level circuitry.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate manufacturer documentation and approved CPR test equipment
- Repaired or configured only by qualified personnel
After repair, repeat CPR feedback verification and all required return-to-service testing before clinical use.
Knowing when inaccurate feedback requires escalation rather than continued substitution is proper troubleshooting.
Clinical Use Tip
During active resuscitation, questionable CPR feedback should never cause rescuers to interrupt otherwise effective chest compressions.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported that the Propaq MD recognized the CPR sensor but displayed inconsistent compression-depth feedback."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the CPR sensor shifting on a soft support surface during compressions, introducing movement unrelated to actual chest displacement."
Resolution
What action was taken.
Example:
"Repeated testing with correct sensor positioning on an appropriate firm test setup, verified stable rate and depth feedback, and returned the device to service."
Helpful Details to Include (If Known)
- Whether depth, rate, or both were incorrect
- Sensor recognition status
- CPR sensor physical condition
- Connector condition
- Sensor placement
- Mattress or support surface used
- Whether the issue occurred during transport
- Known-good sensor substitution result
- Results using a controlled test setup
- Whether the fault followed the sensor
- Final device status
Final Thought
Maintain uninterrupted patient care, verify placement and external motion before blaming the monitor, isolate the sensor from the defibrillator with controlled testing, and escalate any feedback system that cannot be proven reliable.
That is successful troubleshooting.