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What This Guide Helps With
Troubleshooting reported pacing failure, absent pacing output, or suspected non-capture while separating patient-related concerns from device, electrode, cable, or setup issues.
Step-by-Step Troubleshooting
Ensure Patient Safety First
Do not troubleshoot suspected pacing failure while the LIFEPAK 35 is being relied upon for active patient therapy.
If pacing is required and capture is absent or uncertain:
- Have clinical staff transition immediately to another verified pacing-capable defibrillator.
- Remove the suspect LIFEPAK 35 from clinical use for controlled evaluation.
- Do not repeatedly test pacing output on a patient to determine whether the problem will recur.
Expected: Patient care continues with a known-good device.
Why it matters: The LIFEPAK 35 is intended to provide non-invasive pacing, but apparent “no capture” does not by itself prove device failure. Stryker identifies non-invasive pacing as a therapy function of the LIFEPAK 35.
Clarify What “Pacing Failure” Actually Means
Interview the reporting clinician and determine whether the complaint was:
- Pacer would not enter pacing mode
- Pacing rate could not be adjusted
- Pacing current could not be increased
- No pacing markers appeared
- No visible pacing artifact was observed
- Device displayed a lead or electrode-related message
- Electrical pacing appeared present but mechanical capture was not achieved
- Capture was initially present and then lost
- Concern occurred only with one electrode set or therapy cable
Review available event information and device logs when accessible.
Expected: The complaint is narrowed to a reproducible device-function concern rather than the broad statement “pacer failed.”
Why it matters: A patient who does not achieve capture is not automatically evidence of defective pacing output.
Inspect the Device for Obvious External Damage
With the unit removed from patient use, inspect:
- Therapy cable and connector
- Cable strain reliefs
- Connector pins and contact surfaces
- Therapy electrode packaging
- Electrode expiration date
- Electrode gel condition if packaging integrity is questionable
- Device therapy connector
- Evidence of fluid intrusion
- Impact damage
- Contamination or debris
- Unusual heat or odor
Do not use damaged, expired, opened, dried, or questionable therapy electrodes for evaluation.
Expected: Therapy-path components are physically intact and suitable for testing.
If damage is found: Replace the affected approved accessory and retest. If the issue resolves, document the finding and stop.
Verify Therapy Cable and Electrode Compatibility
Confirm that the connected therapy cable and disposable therapy electrodes are approved and appropriate for the LIFEPAK 35 configuration being evaluated.
Check that:
- Connectors are fully seated
- No adapter is loose
- No connection is partially engaged
- The cable is not under excessive tension
- The electrode set is correctly connected to the therapy cable
Expected: A complete and secure external therapy path is established.
If reseating or replacing the external accessory resolves the issue: Complete verification testing, document the corrective action, and stop.
Rule Out a Single Defective Electrode Set
When safe and consistent with department procedure, replace the suspect electrode set with a known-good compatible set for bench evaluation.
Do not assume the defibrillator is defective based on one set of disposable electrodes.
Expected: The complaint either clears with replacement electrodes or remains present with known-good accessories.
If the issue clears: The original electrode set or connection was the likely cause. Stop after required verification.
Rule Out a Therapy Cable Problem
If the concern persists, repeat the controlled evaluation using a known-good compatible therapy cable when available.
Pay particular attention to intermittent behavior caused by:
- Cable movement
- Connector movement
- Strain near cable ends
- Intermittent lead-off behavior
- Changing impedance or connection indications
Expected: Pacing behavior remains stable with a known-good cable.
If the problem follows the original cable: Remove that cable from service, replace it, perform required verification, and stop.
Verify Pacing Mode Setup and Observable Device Response
Using an appropriate simulator or defibrillator analyzer rather than a patient, verify that the LIFEPAK 35:
- Enters the intended manual pacing function
- Displays the expected pacing interface
- Accepts pacing rate adjustments
- Accepts pacing current adjustments
- Shows appropriate pacing-related indicators or markers
- Does not display persistent connection, therapy, or service faults
The LIFEPAK 35 supports manual mode for noninvasive pacing, and Stryker documentation describes on-screen pacing guidance.
Expected: Pacing controls respond normally and the device behaves consistently as settings are changed.
If controls do not respond or pacing mode behaves abnormally: Stop routine troubleshooting and escalate for service evaluation.
Test Pacing Output With an Appropriate Defibrillator Analyzer
Connect the LIFEPAK 35 to a compatible calibrated defibrillator analyzer using the correct approved test setup.
Verify pacing performance according to your organization’s approved inspection procedure, including applicable checks for:
- Pacing output
- Pacing rate
- Response to setting changes
- Consistency of delivered pulses
- Intermittent output loss
- Relevant load conditions supported by the test setup
Stryker publishes a LIFEPAK 35 Performance Inspection Procedure specifically supporting controlled performance verification, and its official service documentation addresses maintenance and testing.
Expected: Measured pacing performance meets the applicable manufacturer procedure and local acceptance criteria.
If measured output is normal: Do not conclude that the defibrillator failed solely because clinical capture was absent.
If output is missing, intermittent, or outside acceptance criteria: Remove the device from service and escalate for repair.
Attempt to Reproduce the Reported Failure Under Controlled Conditions
If initial analyzer testing passes, repeat controlled checks while observing for:
- Failure after startup
- Failure after reconnecting the therapy cable
- Intermittent output during gentle external cable movement
- Loss of output after mode changes
- Recurring service indicators
- Inconsistent rate or current response
- Repeated electrode or impedance-related messages
Do not perform destructive testing or open the unit solely to chase an intermittent complaint.
Expected: The unit remains stable through repeated controlled checks.
If the failure recurs: Capture the exact behavior, remove the unit from service, and escalate.
Review Device Logs and Reported Error Information
Review available service or event information for faults occurring near the reported incident.
Document:
- Exact error or service code
- Date and time
- Whether the fault was active or historical
- Whether the complaint occurred during pacing
- Associated lead-off or connection behavior
- Whether the issue repeated during bench testing
Expected: No unresolved therapy-related fault remains unexplained.
If a pacing or therapy-related fault is active or recurring: Escalate using the applicable Stryker service information rather than clearing the device for use based only on a successful power cycle.
Perform the Applicable Post-Service Performance Verification
After replacing an external accessory or completing authorized service, perform the required functional and performance verification before return to use.
At minimum, confirm applicable:
- Startup behavior
- Display and control operation
- Therapy cable recognition
- Pacing mode operation
- Pacing output performance
- Pacing rate performance
- Alarm and indicator behavior
- Overall operational readiness
Use your approved procedure and the applicable Stryker LIFEPAK 35 performance inspection requirements.
Expected: The device passes all required acceptance checks without recurrence.
If the device passes and the cause was corrected: Return to service according to department policy and stop.
If the Problem Persists
If known-good electrodes, therapy cables, secure connections, correct setup, and controlled analyzer testing do not resolve the concern, common external causes have been ruled out and an internal therapy-system fault is more likely.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
Escalate for qualified evaluation using the applicable Stryker service procedure. Do not proceed into internal therapy circuitry, high-voltage assemblies, or board-level repair unless specifically trained and authorized.
Knowing when to stop is proper troubleshooting. The LIFEPAK 35 has manufacturer-specific service and performance inspection documentation for qualified technical evaluation.
Clinical Use Tip
Never equate electrical pacing activity with confirmed patient capture. Clinical staff must assess capture using appropriate clinical methods and patient response. Clinical Engineering should verify device output with proper test equipment, not by troubleshooting on an active patient.
Do not troubleshoot on an active patient. Move the patient to a backup device first and maintain therapy continuity.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported that the LIFEPAK 35 entered pacing mode but the patient did not appear to capture during transcutaneous pacing."
Cause
What was observed during troubleshooting.
Example:
"Bench evaluation found intermittent therapy connection behavior that followed the pacing/therapy cable and resolved when a known-good compatible cable was installed."
Resolution
What action was taken.
Example:
"Removed the defective therapy cable from service, installed a verified replacement, confirmed pacing output and rate with a defibrillator analyzer, and completed operational testing successfully."
Helpful Details to Include (If Known)
- Active patient safely transferred to another device
- Exact meaning of “no capture” clarified
- AC/battery status recorded
- Therapy cable inspected
- Therapy connector inspected
- Known-good cable tested
- Electrode type and expiration checked
- Known-good electrodes tested
- Pacing mode entered successfully
- Rate control behavior recorded
- Current control behavior recorded
- Pacing markers observed
- Analyzer output measured
- Intermittent behavior checked
- Exact alarm or error recorded
- Service indicator status recorded
- Unusual heat or smell noted
- Final device status documented
Final Thought
A reported pacing failure requires careful separation of patient non-capture from actual device output failure. Protect the patient first, verify external accessories and connections, objectively test pacing performance with appropriate equipment, and escalate unresolved therapy faults without unnecessary internal disassembly. Clear CCR documentation preserves both the clinical complaint and the technical evidence.
That is successful troubleshooting.