8.5 Inspection of Flexible Scopes

Why Flexible Scopes Are Different

A flexible endoscope is a long, narrow, multi-channel, watertight device with moving control cables and delicate fibre or chip imaging. Nearly every characteristic that makes it clinically useful makes it hard to clean and easy to damage. It is the device class most frequently implicated in reprocessing-related infection reports, and it is why the CBSPD outline names scopes explicitly.

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Anatomy

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The Leak Test

Perform a leak test before immersion, on every scope, every time. This is the single most important flexible-scope practice and the most commonly examined.

1. Attach the leak tester and pressurise the scope per the manufacturer's instructions.
2. Observe the pressure holding. On a wet test, immerse and watch for a continuous stream of bubbles, angulating the bending section through its full range while submerged so a hidden defect opens.
3. Also inspect the distal tip, biopsy port, and channel openings for bubbles.

If the scope fails the leak test, it is not immersed. Fluid entering a breached scope reaches the imaging bundle, the angulation wires, and the electronics, converting a repairable puncture into a major repair or a write-off. A failed scope is dried externally per the manufacturer's guidance, tagged, documented, and sent for repair.

The leak test is also the reason a scope is never put straight into a sink at the start of reprocessing.

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External Inspection

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Functional Checks

1. Angulation: deflect the tip through full travel in every direction (up/down and, where fitted, left/right). Motion must be smooth, reach full deflection, and return fully to neutral when released. Sluggish or incomplete deflection indicates stretched or damaged angulation wires.
2. Angulation lock: engages and holds; releases cleanly.
3. Air, water and suction: confirm flow through each channel per the manufacturer's test procedure.
4. Image: connect to the processor and confirm a clear image; on fibre scopes, count black dots as broken image fibres.
5. Illumination: even, bright light output from the light guides.

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Channel Inspection

External inspection cannot assess a channel, so:

• Brush every channel with a correctly sized brush, passing it completely through so it exits the far end, and inspect the brush after each pass. Brushes are inspected for missing or splayed bristles and replaced or reprocessed per policy.
• Flush and verify each channel per the manufacturer's procedure.
• Borescope the channels on the schedule the facility's policy sets. Borescope inspection reveals retained soil and biofilm, scratches and gouges in the channel wall that harbour organisms, internal corrosion, and damage at bends — none of which is visible any other way.
• Document channel inspection findings; scratched or corroded channels are a repair or retirement decision.

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Drying and Storage

Moisture in a flexible endoscope channel is a growth environment, so drying is a patient-safety step rather than a convenience:

• Purge channels with instrument air per the manufacturer's instructions until dry.
• Store hanging vertically, uncoiled, with valves detached, in a ventilated storage cabinet or a validated drying and storage cabinet.
• Never store a scope coiled in its transport case. Cases are for transport only and are themselves cleaned between uses.
• Follow the facility's policy on hang time and on re-processing after a defined interval.

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Disposition

Reading the Leak Test Rather Than Just Performing It

The leak test is the gate that protects everything downstream, and the exam expects more than "do it before immersion".

Pressurise the scope with its dry leak tester before any contact with fluid, and observe the gauge for the interval the manufacturer specifies. A pressure that holds steady indicates an intact outer sheath, channels, and seals. A pressure that falls indicates a breach somewhere in the system.

Then localise it. With the scope pressurised and submerged, articulate the distal bending section through its full range in every direction while watching for a stream of bubbles. Articulation is essential because the bending rubber stretches, and a defect there may only open under flexion — a static submerged scope can look sound and still be perforated. Watch the bending section, the insertion tube, the distal tip, the biopsy port, and the umbilical and connector in turn.

A scope that fails the leak test is removed from the process immediately and sent for repair without being immersed. Immersing a leaking scope drives fluid into the interior, converting a small, cheap seal repair into a catastrophic internal failure costing many times more.

Channel Inspection and the Borescope

The internal channels are the highest-risk and least visible part of a flexible scope, and visual external inspection tells you nothing about them.

Verify each channel is patent by flushing and observing flow, and confirm the brushes used are the correct diameter and length for that channel and that the brush bristles emerge intact at the far end. A brush that returns with bent or missing bristles has been used in the wrong channel or is worn out.

Where the department has one, use a borescope to inspect channel interiors directly. Borescopy commonly reveals findings no other method detects — retained fluid, discolouration, scratches and gouges, adhesive failure at channel junctions, and residual debris — and these findings are the basis for removing a scope from service.

The Findings That Mandate Removal

Be decisive about disposition, because ambiguity here is how contaminated scopes stay in circulation.

Remove the scope from service for: any leak; cracks, splits, or bubbling in the bending rubber; dents, kinks, or bulges in the insertion tube; a distal lens that is scratched, chipped, or will not clean; articulation that is loose, unresponsive, or will not return to neutral; channel damage on borescopy; and any fluid seen inside the optics.

After processing, scopes must be dried thoroughly and hung vertically, uncoiled, with valves detached, in a controlled storage cabinet. Residual moisture in a stored channel supports biofilm formation, which is the failure that no amount of subsequent inspection will detect.