The federal Food and Drug Administration (FDA) astutely concludes in its notice in the Federal Register that “the adequate reprocessing of reusable medical devices is a critically important factor in protecting patient safety.”(2)

To achieve this outcome, however, several criteria must be met, including that the reusable device’s instructions—often referred to as the device’s “IFUs,” or instructions for use—be clear, succinct and consistent, no matter the device type. Otherwise, users may become confused, posing an increased risk of improperly reprocessing the device and of transmitting diseases.

Discussion

For more than two decades, confusion and ambiguity have surrounded the claim of liquid chemical sterilization.(21-33) Indeed, published reports, including those by the FDA, suggest that the outcome of processes labeled with this claim may be more akin to disinfection.

For instance, the FDA’s draft guidance document on the reprocessing of medical devices — dated May 2, 2011, and yet to be published; click here to read this document — ostensibly equates liquid chemical sterilization with high-level disinfection, as if the two processes are comparable and interchangeable.(9)

Discussing in the same context these two processes—which both require the instrument be immersed in a liquid chemical sterilant/high level disinfectant, followed by water rinsing—this FDA draft guidance document states that:(9)

active device drying is another post-processing procedure which may reduce or eliminate re-contamination of unwrapped devices after high level disinfection/liquid chemical sterilization reprocessing of devices because they will be wet at the end of reprocessing. *

(* Whether the FDA recommends drying the processed, wet instruments after completion of a process labeled to achieve liquid chemical sterilization both between patient procedures and before storage is unclear, although it is an important issue to resolve (see: p. 19 of the FDA’s draft document).(9)

Further, the FDA states that:

  • biological indicators (BIs) “are not appropriate (or required) for monitoring liquid chemical sterilization process(es)”;(21)
  • the terminal water rinse produced by liquid chemical sterilization processes is not sterile;(21,22) and
  • liquid chemical sterilization is not associated with a sterility assurance level (SAL)(21-33)—each limitation of which is similarly shared by processes labeled to achieve high-level disinfection.(31)

Consistent with these three limitations, the FDA has also published that instruments exposed to liquid chemical sterilization, like those exposed to high-level disinfection, “are not sterile.”(22)

( Almost not warranting mention, a process labeled to achieve sterilization is associated with a sterility assurance level (SAL), can be monitored on-site using biological indicators (BIs), and, of course, renders the processed instrument sterile.)

 

The reservations of Dr. Lawrence F Muscarella, this article’s author, about the unique claim of “liquid chemical sterilization” were expressed on the front pages of both The Wall Street Journal (click here) and of Investors Business Daily (click here) (32,33).

More discussion

Yet, these limitations notwithstanding, the FDA’s draft guidance document(9) on the reprocessing of medical devices also confusingly discusses liquid chemical sterilization in its description of steam, ethylene oxide gas, gas/plasma, dry heat, and chemical vapor sterilizers, almost as if liquid chemical sterilization achieves an outcome distinct from, and assuredly higher than, high-level disinfection and, possibly, more similar to that of these other listed sterilizers.

Note: The FDA defines liquid chemical sterilization(21) less by what this claim actually achieves than by its shortcomings and what it does not achieve.

More confusion

The claim of liquid chemical sterilization remains as confusing to some today as in 1988 (see: Box B, below), when it was first  introduced.(5,7,21,22,32,33)

Similarly confusing are the nuanced IFUs of a liquid chemical sterilant processing system that the FDA cleared in 2010.(22)

Click here to read Dr. Muscarella’s related article “History of the STERIS System 1: A Detailed Review.”

The FDA cleared this device for liquid chemical sterilization while acknowledging, if oxymoronically, that this system’s processed instruments, like its filtered rinse water, “are not sterile.”(21,22)

Whether confusion about liquid chemical sterilization—namely, what systems labeled with this claim actually do and do not achieve—has caused healthcare-associated infections (HAIs) is unclear, although systems with this claim have been federally rebuked and their use linked to HAIs.(5-7,25,26,28,32)

Action

The FDA is respectfully requested to consider mitigating this confusion and clarifying for manufacturers and healthcare practitioners its definition of liquid chemical sterilization (like, too, its definition of sterile; see: main article).

No doubt, a device’s clear and consistent labeling, IFUs, reprocessing instructions, FDA clearance, and intended uses, like its operating instructions, are crucial to prevent user confusion, improve the quality of instrument reprocessing, minimize the risk of disease transmission and HAIs, and ensure the device’s safe and effective use.

The processed instruments, like the terminal rinse water, are not sterile,(21,22) which would seemingly belie the claim of “sterilization.”

Box B: “Liquid chemical sterilization,” as defined by the FDA. This blog has published for years several articles expressing concerns about the safety and effectiveness of liquid chemical sterilization.

Dr. Muscarella’s reservations about this claim were expressed on the front pages of The Wall Street Journal (click here) and of Investors Business Daily (click here) (32,33).

In short, the claim of liquid chemical sterilization can convey a false sense of security by implying a sterility assurance level (SAL) with which it is not associated (21-33).

The processed instruments, like the terminal rinse water, are not sterile,(21,22) which would seemingly belie the claim’s validity and appropriateness for use in operating-room settings.

That the FDA defines liquid chemical sterilization less in terms of its effectiveness and by what it actually achieves than by its limitations and what it does not achieve only adds to the confusion.(21,22)

References: The references to this article (see the parenthetical numbers, above) to this article may be read here.

Article by: Lawrence F Muscarella PhD on 1/10/2013; updated 7-14-2014, Rev A.

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