On this page
Asset Type
Manufacturer
Model
What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting occlusion or line blockage alarms on a Medfusion 3500 syringe infusion pump. These alarms occur when the pump detects excessive pressure in the infusion line, indicating that fluid flow may be restricted.
Most occlusion alarms are caused by external issues such as tubing problems, closed clamps, or downstream flow restrictions rather than internal pump failure. This guide focuses on verifying these common causes before assuming a pump malfunction.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- If the pump is connected to a patient, coordinate with clinical staff to transition the infusion to another pump before performing troubleshooting.
- Patient safety always takes priority.
Confirm the Alarm Message
- Verify the exact alarm shown on the screen (such as “Occlusion,” “Downstream Occlusion,” or similar message).
- Confirm whether the alarm occurs immediately upon starting infusion or after the pump has been running.
- Immediate alarms often indicate setup issues, while delayed alarms may indicate gradual pressure buildup.
Check for Closed Clamps in the Infusion Line
- Inspect the entire tubing set for any closed roller clamps or slide clamps.
- Common locations include:
- IV tubing clamp
- Extension set clamp
- Clamp near the syringe
- Even a partially closed clamp can trigger an occlusion alarm.
Inspect the Tubing Path for Kinks or Compression
- Trace the infusion line from the syringe to the patient connection point.
- Look for sharp bends or kinks in tubing.
- Check for tubing caught under equipment or bed rails.
- Look for compression from IV pumps, rails, or tape.
- Correct any obstruction and restart the infusion.
Check the Syringe Installation
- Confirm the syringe is correctly seated in the pump and secured by the syringe clamp.
- Verify the correct syringe size is selected in the pump settings.
- Ensure the syringe plunger is aligned with the drive mechanism.
- Check for misalignment or obstruction at the plunger pusher.
- Improper syringe placement can create abnormal pressure readings.
Verify Correct Syringe Type and Size
- Confirm that the installed syringe matches the syringe type programmed in the pump.
- Example issues include the pump being programmed for a different syringe brand or the incorrect syringe size being selected.
- Incorrect syringe profiles can cause inaccurate pressure detection and occlusion alarms.
Inspect the Pressure Sensor Area
- Look at the area where the tubing or syringe interacts with the pump’s pressure sensing components.
- Check for debris or fluid contamination.
- Verify proper tubing placement.
- Do not attempt internal disassembly.
Replace the Tubing Set or Syringe
- If external restrictions are not identified, replace the tubing set and/or syringe with a new sterile set.
- Tubing defects or partially occluded filters can cause repeated alarms.
Restart the Pump and Observe Operation
- After correcting or replacing components, restart the infusion.
- Monitor for repeated occlusion alarms.
- Observe the pump during initial flow.
- If the pump operates normally, the issue was likely related to tubing or setup.
If the Problem Persists
If occlusion alarms continue after verifying clamps, tubing, syringe installation, and replacing disposable components, the issue may involve:
- Pressure sensor malfunction
- Drive mechanism problems
- Internal calibration issues
At this point the device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
Recognizing when external causes have been ruled out is an important part of proper troubleshooting.
Clinical Use Tip
Never troubleshoot infusion pumps while they are actively delivering medication to a patient.
Always ensure the infusion is safely transferred to another pump before removing the device from service.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Nursing reported Medfusion 3500 pump repeatedly alarming for ‘Occlusion’ during infusion.”
Cause
What was observed during troubleshooting.
Example:
“Inspection revealed IV tubing kinked under patient bed rail causing downstream flow restriction.”
Resolution
What action was taken.
Example:
“Tubing repositioned and infusion restarted. Pump tested and operated normally without further occlusion alarms.”
Helpful Details to Include (If Known)
- Outlet tested (if applicable)
- Tubing clamps inspected
- Tubing set replaced
- Syringe type verified
- Alarm messages observed
- Physical line obstructions checked
- Final device status (returned to service or removed)
Final Thought
Occlusion alarms are designed to protect patients by detecting restricted medication flow. Most alarms are caused by simple setup or tubing issues rather than pump failure. A logical approach—starting with clamps, tubing, and syringe setup—helps resolve many issues quickly while ensuring patient safety. When external causes have been ruled out, removing the device from service for repair is the appropriate action.
That is successful troubleshooting.