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Manufacturer
Model
What This Guide Helps With
Sensor not recognized, intermittent readings, or low perfusion errors caused by probe issues, connection problems, or patient-related factors.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Remove the device from active patient monitoring if readings are unreliable.
- Transfer monitoring to a known working pulse oximeter.
Expected: Patient remains safely monitored on alternate equipment
Why it matters: Inaccurate SpO₂ readings can delay recognition of hypoxia
Verify the Reported Issue
- Power on the device and observe behavior.
- Check for:
- “Sensor Not Detected” message
- Low perfusion or weak signal indicators
- Intermittent or no SpO₂ readings
Expected: Issue is clearly confirmed
Why it matters: Ensures this is not user error or transient condition
Check Sensor Connection (Most Common Cause)
- Inspect where the sensor connects to the device.
- Ensure connector is fully seated.
- Disconnect and reconnect firmly.
- Inspect for bent pins or debris.
Expected: Device recognizes sensor after reconnection
Why it matters: Loose or damaged connections are the most frequent cause
Inspect Sensor and Cable Condition
- Examine the probe and cable for damage.
- Look for:
- Cracked housing
- Frayed or exposed wires
- Dirty or obstructed emitter/detector surfaces
- Clean sensor if visibly soiled.
Expected: Clean, intact sensor provides stable readings
Why it matters: Damaged or contaminated sensors impair signal transmission
Try a Known Good Sensor
- Swap with a verified working Masimo-compatible sensor.
- If resolved, remove defective sensor from service.
Expected: Device detects sensor and provides stable readings
Why it matters: Quickly isolates whether the issue is sensor-related
Check Patient Application and Site
- Ensure proper placement (finger fully inserted).
- Remove nail polish or artificial nails.
- Warm cold extremities if needed.
- Try alternate site (ear, toe, different finger).
Expected: Improved signal strength and stable readings
Why it matters: Poor perfusion or improper placement can mimic device failure
Assess Environmental and Motion Factors
- Minimize patient movement.
- Shield from bright ambient light if necessary.
Expected: Signal stabilizes
Why it matters: Motion and light interference can cause low perfusion errors
Perform a Power Reset
- Turn the device off.
- Wait 10–15 seconds.
- Power back on.
Expected: Device reinitializes and detects sensor
Why it matters: Clears temporary communication faults
If the Problem Persists
If all external causes (sensor, cable, application, environment) have been ruled out, the issue is likely internal (sensor port, internal circuitry, or signal processing failure). Remove the device from service, label it Out of Service, and send for repair or bench evaluation.
Clinical Use Tip
Do not troubleshoot sensor or signal issues on an actively monitored patient. Always transition the patient to a reliable monitoring device first.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Pulse oximeter not detecting sensor and showing low perfusion error."
Cause
What was observed during troubleshooting.
Example:
"Damaged sensor cable causing intermittent signal loss."
Resolution
What action was taken.
Example:
"Replaced sensor with known good unit and verified proper operation."
Helpful Details to Include (If Known)
- Sensor connection checked and reseated
- Alternate sensor tested
- Probe condition (clean/damaged)
- Patient site and perfusion status
- Device power cycle performed
- Final device status (working or removed from service)
Final Thought
Effective troubleshooting starts with simple, external checks—connections, sensors, and patient factors—before assuming device failure. Prioritize patient safety, follow a logical process, and escalate appropriately when internal faults are suspected. Clear documentation ensures continuity and accountability.
That is successful troubleshooting.