Understanding thermal disinfection; reusable endoscope connectors

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Q We recently changed some of the detergents we use in our washer disinfector. When the rep came in to do implementation, she suggested we make some temperature adjustments to our wash phase to maximize the detergent’s performance. She also stated that she didn’t think our final rinse temperature was adequate for thermal disinfection. I told her I wasn’t that concerned about that because our drying temperature was well above the required 180 degree disinfection temperature and would certainly be more than adequate to achieve thermal disinfection during the dry phase. She suggested I might want to look into the matter. Am I correct in my thinking?

A The final rinse phase in a washer disinfector is when thermal disinfection actually takes place. The hot water, at a minimum of temperature of 180 degrees, acts as a conduit which delivers the required temperature to all of the surfaces and crevices of the instruments and other items in the washer. During the dry-phase hot air is merely blown over the instrument’s outer surface. Although the dry-phase temperatures may be at much higher temperatures, well above 200°, it could take an excessive amount of time before the entire washer contents are heated to the required temperature to achieve thermal disinfection.

This would be somewhat similar to the difference between saturated-steam sterilization and dry-heat sterilization. We know that steam sterilization is a faster process than dry-heat sterilization because the saturated-steam is capable of reaching external and internal surfaces of load contents. Steam is basically vaporized water which acts as the conduit to deliver the moist heat at the required high temperatures (250° to 270°) to achieve sterilization within minutes.

On the other hand, dry-heat sterilization utilizes temperatures ranging from 320° to 350° and beyond and depending on the load contents it could take several hours for all items to “heat up” and reach the required sterilization temperature. It is important that you consult your washer manufacturer’s instructions for use (IFU) and ensure that each phase of your washer cycle is in compliance with the manufacturer’s instructions and that the thermal-disinfection (final rinse) phase meets the required temperature and time parameters

Q I am the endoscopy services nurse manager. Recently the central sterile processing supervisor has taken over the supervision of scope reprocessing in the Endoscopy unit. He has implemented several changes such as testing all scopes for residual soils prior to disinfection. We previously were doing random testing of 5 percent of all scopes. Increasing the testing to include all scopes has increased reprocessing expenses significantly. I believe this is an unnecessary step and expense. After manual cleaning the scopes are run through an AER which disinfects them. He has also told us that we need to discontinue the use of reusable endoscope connectors per some FDA mandate stating they cannot be adequately cleaned. I’m all in favor of patient safety but some of this sounds a bit much. Can you help me out here?

A There have been countless studies published, which have found that an extremely high percentage of processed scopes have been found to test positive for residual organic soils both pathogenic and non-pathogenic. Endoscopes by their complex design, present many challenges to the cleaning process, even when complying with IFUs. Processing equipment such as AERs, with a washing cycle, may fail. If any soil residuals remain on a medical device, it will present a barrier to successful disinfection.

FDA did issue an alert for endoscope connectors that are labeled for use with multiple patients over the course of a 24-hour period without reprocessing. These connectors are known as 24-hour multi-patient-use endoscope connectors. FDA had not received acceptable testing to demonstrate the safe use of these products, and thus has recommended against their use. The FDA encourages healthcare providers and facilities to:

1. use single-use endoscope connectors with backflow prevention features, or
2. use reusable endoscope connectors with backflow prevention features and ensure that those reusable connectors are reprocessed according to their instructions for use prior to each patient procedure.

You can continue to use your reusable connectors so long as they comply with #2 above. I have found that most facilities are reprocessing their reusable connector after each use. Cleaning and disinfection failures of endoscopes have resulted in many nosocomial infections and patient deaths. The quality assurance of all processed scopes and other medical devices is critical to patient safety and welfare. I am a believer that every scope should be tested prior to patient use. Would you want a scope that was not tested used on you or a loved one?