Kendall SCD 700 Series

Asset Type

Sequential Compression Device (SCD)

Manufacturer

Cardinal Health

Model

Kendall SCD 700 Series

What This Guide Helps With

This guide provides a structured Clinical Engineering approach when a Kendall SCD 700 Series delivers compression pressure that appears:

• Too low
• Weak during inflation
• Inconsistent between cycles
• Uneven between left and right legs

The focus is on logical, external, and easily verifiable causes before assuming internal pump, valve, or pressure sensor failure.

Step-by-Step Troubleshooting

1. Confirm Therapy Mode and Active Cycle

• Verify correct therapy mode (calf vs. thigh).
• Confirm therapy is actively running and not paused or in standby.
• Observe at least one full inflation/deflation cycle.

Incorrect mode selection or incomplete startup can mimic low-pressure delivery.

2. Check Sleeve Application and Fit

• Ensure sleeves are wrapped snugly and evenly.
• Confirm proper sleeve size for the patient.
• Verify hook-and-loop closures are fully secured.
• Check that bladders are aligned correctly with the limb.

Oversized or loosely applied sleeves often feel like low pressure even when the unit is functioning properly.

3. Inspect Tubing for Leaks or Obstructions

• Examine entire tubing length for cracks, splits, or pinholes.
• Check for loose fittings at both ends.
• Look for kinks, sharp bends, or compression under bed rails or equipment.
• Inspect for partially disconnected quick-connect fittings.

Even a small air leak significantly reduces delivered compression pressure.

4. Reseat All Connections at the Ports

• Fully disconnect and reconnect tubing at both device ports.
• Ensure connectors click or seat completely.
• Listen for escaping air during inflation.
• Gently move connectors while the unit is inflating to check for intermittent leaks.

Partially seated connectors are a common cause of inconsistent pressure.

5. Swap Sleeves and Tubing

• Swap left and right sleeves.
• Replace tubing with a known-good set if available.
• Observe results:
• If the issue follows the sleeve → sleeve likely leaking.
• If the issue follows the tubing → tubing defective.
• If the issue remains on the same device port → possible internal valve or channel issue.

This step helps isolate accessory failure from internal device failure.

6. Listen to Pump Operation

• During inflation:
• Pump sound should be smooth and consistent.
• No excessive strain, grinding, or rapid short cycling.
• No unusually loud or weak-sounding motor activity.

Rapid cycling without building pressure often indicates a leak or internal valve malfunction.

7. Check for Alarms or Error Messages

• Look for:
• Leak detected
• Pressure fault
• System error
• Record the exact alarm wording for documentation.

8. Compare Both Channels

• Swap tubing between ports.
• Observe whether low pressure follows the tubing or remains with the device port.
• If the issue remains isolated to one port after accessory swaps, internal channel components are likely involved.

If the Problem Persists

If pressure remains low or inconsistent after completing these steps, common remaining causes include:

• Internal pump wear
• Valve manifold failure
• Pressure sensor drift
• Internal air leak

These are not field-correctable.

Next Steps:

• Remove the unit from clinical service
• Label clearly as Out of Service
• Send for repair or bench evaluation

Knowing when to stop bedside troubleshooting is proper Clinical Engineering practice.

Clinical Use Tip

Do not troubleshoot pressure concerns while sleeves are actively connected to a patient.

Transfer the patient to a functioning SCD unit first.

Verify DVT prophylaxis therapy continues uninterrupted.

Perform troubleshooting only when patient safety is ensured.

Never compromise active therapy to investigate equipment performance.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
“Compression pressure weak and inconsistent on left leg.”

Cause

What was observed during troubleshooting.

Example:
“Sleeves and tubing inspected and swapped; issue remained on left port. Suspected internal valve or pump degradation.”

or

“Issue followed sleeve when swapped. Sleeve found leaking.”

Resolution

What action was taken.

Example:
“Replaced defective sleeve; unit returned to service.”

“Removed device from service and sent for bench evaluation due to suspected internal pressure channel failure.”

Helpful Details to Include (If Known)

• Side affected (left / right / both)
• Exact alarm message wording
• Sleeve size used
• Sleeve swapped: yes / no
• Tubing replaced: yes / no
• Pump audible and consistent: yes / no
• Leak heard at connections: yes / no
• Final device status (returned to service / sent to repair)

Final Thought

Most low-pressure complaints are caused by loose connections, accessory leaks, incorrect sleeve sizing, or incomplete setup — not internal pump failure.

A logical, step-by-step approach:

• Protects patient therapy
• Prevents unnecessary device replacement
• Ensures accurate documentation
• Identifies true internal failures when present

That is successful troubleshooting.