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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting DASH 5000 monitors when cardiac output (CO) or cardiac index (CI) values appear inconsistent, fluctuate unexpectedly, or differ from expected trends. This may occur during hemodynamic monitoring using invasive or minimally invasive cardiac output measurement systems. The guide focuses on external and user-level checks first before considering internal sensor or monitor faults.
Step-by-Step Troubleshooting
Confirm Patient Setup and Catheter Integrity
- Ensure the CO/CI catheter (e.g., thermodilution or arterial line with CO module) is correctly placed and patent.
- Check for kinks, clots, or loose connections.
- Reason: Faulty lines or incorrect placement are the most common cause of inconsistent CO readings.
Verify Zeroing and Calibration
- Ensure the invasive pressure transducers and CO module are properly zeroed and calibrated per hospital protocol.
- Re-zero the transducer at the phlebostatic axis.
- Reason: Drift or improper calibration can directly affect CO/CI calculations.
Check for Air Bubbles or Line Occlusion
- Inspect the fluid-filled system for microbubbles or occlusions.
- Flush lines gently if necessary.
- Reason: Air bubbles or partial blockages can cause erroneous thermodilution readings.
Assess Temperature Injection Technique (if thermodilution CO)
- Confirm consistent injection volume, speed, and temperature of saline bolus.
- Reason: Variations in bolus technique cause wide swings in measured CO.
Check Module and Cable Connections
- Ensure CO/CI module is fully seated and all cables are secure.
- Inspect cables for damage, corrosion, or intermittent connections.
- Reason: Loose or damaged connections can introduce intermittent signal errors.
Review Trend and Measurement Settings
- Verify monitor is set to the correct measurement method (continuous vs. bolus) and averaging interval.
- Reason: Incorrect averaging can make CO/CI appear inconsistent even if actual values are stable.
Power Cycle Monitor if Safe
- If all external checks are normal and patient safety allows, perform a monitor restart.
- Reason: Temporary software glitches can cause inconsistent readings.
If the Problem Persists
All external causes (line issues, calibration, connections, technique) have been ruled out. The CO/CI module or monitor is likely faulty.
- Remove the monitor from service.
- Label it Out of Service.
- Send the device for vendor repair or in-house bench evaluation.
Knowing when to stop troubleshooting prevents patient risk and unnecessary internal repairs.
Clinical Use Tip
- Never troubleshoot CO/CI readings on an active patient without ensuring patient stability.
- Move the patient to an alternate monitor or module if available while investigating.
- Always confirm proper catheter placement and zeroing before interpreting values.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
Monitor shows fluctuating or inconsistent cardiac output and cardiac index readings.
Cause
What was observed during troubleshooting.
Example:
Observed normal line placement and zeroing, no occlusions; CO/CI module cable loose intermittently.
Resolution
What action was taken.
Example:
Re-seated module and secured cables; readings normalized. If issue persists, monitor removed from service and sent for evaluation.
Helpful Details to Include
- Transducer zero status
- Catheter type and placement
- CO measurement method (continuous vs. bolus)
- Saline bolus volume and temperature (if applicable)
- Trend data screenshots or printouts
- Cable inspection results
Final Thought
Patient safety and measurement accuracy are paramount. Systematic, logical troubleshooting ensures that external and user-related causes are addressed before escalating to repair. Proper CCR documentation supports clinical decision-making and reduces repeat issues.
That is successful troubleshooting.