HEALTHCARE SELF-STUDY SERIES N


PURCHASING EWS


October 2021 The self-study lesson on this central service topic was developed by 3M Health Care. The lessons are administered by Endeavor Healthcare Media.


Earn CEUs After careful study of the lesson, complete the examination at the end of this section. Mail the completed test and scoring fee to Healthcare Purchasing News for grading. We will notify you if you have a passing score of 70% or higher, and you will receive a certifi cate of completion within 30 days. Previous lessons are available at www.hpnonline.com.


Certifi cation The CBSPD (Certification Board for Sterile Processing and Distribution) has pre-approved this in-service for one (1) contact hour for a period of fi ve (5) years from the date of original publication. Successful


completion of the lesson and post-test must be documented by facility management and those records maintained by the individual until recertifi cation is required. DO NOT SEND LESSON OR TEST TO CBSPD. For additional information regarding certifi cation, contact CBSPD - 148 Main Street, Suite C-1, Lebanon, NJ 08833 • www.cbspd.net.


IAHCSMM (International Association of Health- care Central Service Materiel Management)


has pre-approved this in-service for 1.0 Continu- ing Education Credits for a period of three years, until September 13, 2024. The approval number for this lesson is 3M-HPN 211309. For more information, direct any questions to Healthcare Purchasing News (941) 259-0832.


LEARNING OBJECTIVES


1. Understand the background and make up of chemical sterilization indicators (CIs)


2. Understand the way in which chemical indicators change color during exposure to sterilization processes


3. Understand how and under what circumstances chemical indicators are used


Sponsored by: by Brian Kirk T


Chemical Indicators for monitoring sterilization processes


here are many processes used for the sterilization of single use and re-usable medical devices.1


In industrial settings


where large scale sterilization takes place, physical processes such as irradiation with gamma, e-beam or “soft” X-rays and chemi- cal processes employing ethylene oxide gas, are used. Steam sterilization is extensively used in the Pharmaceutical Industry to pro- duce many water based injectable fl uids. In the healthcare sector such as hospital sterile processing departments (SPDs), or dental surgeries and general practitioner’s offi ces, steam sterilization is the predominant pro- cess used. In hospital SPDs there are some reusable medical devices such as fl exible endoscopes, which need to be sterile but cannot withstand the high temperatures and pressures used in steam sterilization. In these cases, low temperature sterilization processes are used employing ethylene oxide or vaporised hydrogen peroxide. Low tem- perature steam mixed with formaldehyde vapor is also used in some countries, but not in the U.S.


The characteristics that must be monitored within the process are those that kill any microbial contaminants present on the medical device; these are called the process variables.3


steam sterilization, the characteristics of the process which cause microbial kill are the temperature and time of exposure in the presence of moisture.4


Whichever and wherever a sterilization process is used, it must be validated and routinely monitored to ensure ongoing effi cacy.2


There are three basic methods for monitor-


ing sterilization processes. One measures the physical characteristics of the process such as temperature or time of exposure (physical indicators). Another consists of a prepara- tion of bacterial spores, presenting a known resistance to the process, but inactivated by an effi cacious process (biological indicators). The third method consists of a mixture of reactive chemicals (printed on a substrate) that responds to defi ned characteristics of the processes so that visible change is observed after suitable exposure (chemical indicators; CIs). It is the purpose of this series of articles to expand further on this latter approach for monitoring sterilization processes.


CIs for monitoring sterilization processes Historical perspective: Chemical indicators are, in essence, products which give some visual evidence of exposure to a specifi c combination of process variables. Thus, in moist heat sterilization they respond to time and temperature in the presence of moisture when autoclaved. Chemical indicators have been used for many years and textbooks from the early part of the 20th century discuss their use.5,6


One of the earli-


est was a wax plug enclosed within a sealed glass ampoule, called a Diak tube,7


Thus, for example, in designed The steam sterilization


process takes place in a saturated steam envi- ronment in a sealed pressure vessel (called an autoclave), so moisture is present in a more-than-adequate amount. However, the presence of residual air from an inadequate air removal stage during the process or the presence of contaminating gases in the steam supply (called non condensable gases; NCG) can lead to inadequate moisture levels at the surfaces that need to be sterile. This compro- mises the effi cacy of the process.


24 October 2021 • HEALTHCARE PURCHASING NEWS • hpnonline.com


for monitoring steam sterilization processes and still available today. The wax melts at the sterilization temperature indicating that at least this had been achieved but provides no evidence of time of exposure or presence of moisture. Autoclave tape has been used for many decades.8


Several studies have


been conducted to assess CI performance,9, 10 including one in 1958 by the famous microbi- ologist, Kelsey, who proposed the attributes of the ideal chemical indicator.


“The ideal chemical indicator should follow a temperature time curve which runs parallel to that of a pathogenic spore bearing organism but offset by a distance which allows a reasonable margin of safety…… The indicator should show an unequivocal color change which is completed

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