The Folly of Fluid Invasion

The Folly of Fluid Invasion
Fluid Invasion is the cause of many of the most expensive repairs carried out on flexible endoscopes. In addition to the tangible cost of repairs, fluid invasions can shorten the life of an endoscope and create instrument down time that can result in scheduling delays.

Corrosion in the control body was caused by fluid.Any time a flexible endoscope is immersed in water or a cleaning solution a fluid invasion can occur if a leak is present.  Proper leak testing is the easiest way to identify the location of a leak.  If a leak remains undiagnosed for any period of time it can result in significant repair costs related to rusted components, damage and corrosion of electronics, and brittle or weak fiberoptic bundles.

There are several factors that will impact the cost of the repair including:

  • Scope model.
  • Location of puncture, tear or leak
  • How much fluid has invaded the interior of the scope.

Common areas of fluid entry include:

  • Bending Section / Bending Sheath
  • Insertion Tube
  • Control Body / Control Knobs
  • Electronic Connector – on video scopes
  • ETO Port – on fiberscopes.

The Bending Section has a thin, flexible covering that is vulnerable to holes, tears and cuts from any sharp object.  If detected early, through proper leak testing these small leaks can be repaired for $150-$250.  Left undetected, a minor fluid invasion can result in major damage.
The Insertion Tube is sturdier than the bending section, but is susceptible to damage from punctures and bites.  When a leak occurs in the Insertion Tube that is larger than a pinhole, it is critical that the entire tube be replaced. 

Fluid invasion caused extensive rust in this control body.The Control Body is made of plastic and metal that is difficult to damage without impact, but even slight impact can cause the o-rings and seals that join the parts together to misalign and leak. Leaks with the Control Knobs can be particularly problematic and tricky.  During the leak testing procedure it is important to manipulate the control knobs while the scope is adequately pressurized.  Depending on the location of the leak and position of the knobs a leak can be missed or it can become an open floodgate if pressure is not kept on the scope. 
Corrosion in the EC can lead to CCD damage which is very costly to repair.The Electronic Connector has an airtight cap that must be used to cover and seal this delicate part prior to any form of submersion.  The seal on the cap should be checked regularly as a damaged seal or crack in the plastic will render the cap leaky. Corrosion in the EC can lead to CCD damage. Replacing a CCD can cost $5000 or more.

The ETO Port is found on most current models of fiberscopes and has an ETO cap that is used when shipping a scope and during ETO gas sterilization.  However if the ETO cap is left on during submersion it will allow fluid to enter the scope through the ETO port.  One would think that putting a cap on a port would seal it, but with fiberscopes this is the complete opposite.  Remember to remove before submersion. The leak tester mimics the ETO cap but actually seals the port.

The vast majority of repairs related to fluid invasion are preventable. 

A leak can occur at any point in the daily use of an endoscope.  To help avoid fluid invasion damage you should follow the leak testing instructions provided in your equipment manual.  It only takes a few minutes and an inexpensive piece of equipment called a leak tester to avoid instrument downtime, decrease damage and fore go the expensive folly of fluid invasion.