Basics of Steam Sterilization
— TO FLASH OR NOT TO FLASH? by Carol Petro, RN, BSN, CRCST
terilization is the complete destruction of all in the operating room immediately. This is when flash steam
microbial life by physical or chemical proce- sterilizers come into play. Virtually all operating rooms have
dures. There are several methods of sterilization flash sterilizers available adjacent to the operating room suites.
available today, but steam sterilization continues to be the These sterilizers provide for the sterilization of instruments
preferred method to destroy microorganisms. The process that have been dropped on the floor or contaminated during
is non-toxic, safe, sporicidal and relatively inexpensive. the surgical procedure. In addition, these flash sterilizers can
Further, it rapidly heats and penetrates all fabrics. Other be used to sterilize instruments that were not anticipated and
sterilization methods are only used when the item being subsequently not prepared in advance.
sterilized cannot withstand the heat and/or moisture of
steam sterilization. Types of Steam Sterilizers
The sterile processing department prepares instrument There are four basic types of steam sterilizers: gravity air
trays for surgical procedures by assuring that they are displacement, dynamic air removal, washer-sterilizer and
decontaminated, inspected, assembled, wrapped and flash sterilizer.
sterilized prior to patient use. However, there may be times Gravity air displacement sterilizers use gravity to remove
when the instruments are not yet sterile and are needed air from their chambers. Steam introduced into the chamber
creates a layer above the air, which increases until the air is
pushed down through a drain at the bottom of the unit. After
air is removed, steam temperature and pressure builds, and
exposure time begins when the sterilization temperature is
reached. Gravity sterilizers are used to sterilize surgical
instrumentation, liquids and linen.
Dynamic air removal sterilizers (also called prevacuum
or “prevac” steam sterilizers) were created to overcome a
problem that can occur when using saturated steam in
gravity cycles: air can be trapped in the chamber, and cool
air pockets may form and hinder sterilization. PreVac steril-
izers use a pump to remove air from the chamber before
steam is introduced. Dynamic air removal units are, there-
fore, more efficient than gravity air displacement sterilizers
since air is pumped out before steam enters the chamber,
and the steam can immediately penetrate packages. A
Bowie Dick test should be used daily with these sterilizers
to determine if there is residual air in the chamber, which
can prevent steam from reaching all surfaces of the items.
Washer-sterilizers are usually located in areas next or
close to operating room suites. These combination units
wash and sterilize instruments; however, gross contamina-
tion must be removed and rinsed from instruments before
they are processed. These units use a mechanical cycle to
Flash sterilizers are located close to operating room suites
wash and rinse away debris before the sterilization cycle
so dropped instruments can be sterilized quickly. begins. While this processing does not provide terminal
54 MANAGING INFECTION CONTROL January 2009
sterilization for patient use, it does render the instruments temperature of steam to kill microorganisms. Microbes die
safe for handling after the operation. when steam under pressure creates changes in cell structure,
and when cell protein coagulates (thickens into a mass).
Flash sterilizers are typically located near operating room The first steps in sterilization involve proper cleaning
suites. They are used to quickly sterilize dropped instruments (the removal of visible and invisible soil) and decontami-
using cycles with minimum exposure times and temperatures nation (the removal or reduction of infectious organisms
for unwrapped items. Sterilized items must be transferred or other harmful substances). Failure to adequately
immediately from the flash sterilizer to the operating room prepare an item for sterilization hinders the direct steam
using aseptic technique to minimize recontamination from contact needed to destroy microorganisms. Operating
pathogenic organisms. There is considerable risk that flash- rooms run on a tight schedule, but proper decontamination
sterilized items can be contaminated during transport to the of instruments is mandatory. The concern with flash
point of use. The decision to use a flash sterilizer requires sterilization is that in order to accommodate the surgeon
that the benefit of having these instruments is greater than the and schedule, the operating room staff will be pressured
risks associated with the process of flash sterilizing and to eliminate steps, therefore proper decontamination may
transporting these instruments. not occur between surgical procedures. The Association
for the Advancement of Medical Instrumentation (AAMI)
The Basics of the Steam Sterilization Process states that flash sterilization should only be considered if
Steam, by itself, is inadequate to achieve sterilization. Pressure “work practices ensure proper cleaning, decontamination,
that is greater than the atmosphere is required to increase the inspection and arrangement of instruments into the
January 2009 MANAGING INFECTION CONTROL 55
recommended sterilizing trays or other containment be sterilized. All instruments should be opened and disassembled to
devices before sterilization.”1 allow the steam to completely contact items during sterilization.
There are four critical parameters to steam sterilization: The sterilizer should not be overloaded and items should not be
steam, temperature, pressure and time. Steam must be of allowed to contact the sterilizer’s chamber walls.
high quality and contain no more than 3 percent moisture
and a relative humidity (the amount of water vapor) of Monitoring Sterilization Cycles
97 percent. The temperature depends upon the type of Sterility should never be taken for granted. Sterilization cycles
sterilizer used. Gravity air displacement sterilizers require should be routinely monitored using mechanical, chemical and
a temperature of 250°F (121°C). Dynamic air removal, biological indicators.
washer sterilizers, and flash sterilizers require a temperature Mechanical indicators are indicators that come from the
of 270°-275°F degrees (132°C-134°C). To achieve these sterilizer itself to indicate how it has functioned. This may include
temperatures, the pressure must reach 15 pounds per square thermometers, timers, gauges, recorders and/or other devices that
inch (psi) for the 250°F (121°C) setting, and 27 psi to monitor its function. At the end of every cycle, the sterilizer
sterilize at 270°F. printout tape should be checked for:
Exposure times depend upon the sterilizer manufac- Start time and date;
turer’s recommendations based upon load contents. Flash Operator’s initials;
sterilization times usually vary from three minutes to 10 Sterilizer parameters selected (Was the correct cycle and
minutes. If the load consists of a single instrument time selected?);
comprised of metal (nonporous) and without lumens, Sterilizer parameters met (time, pressure, minimum temperature).
a three minute cycle should be used. If the load includes
multiple instruments or instruments with lumens, a 10 Chemical indicators are indicators that verify exposure to
minute cycle should be used.2 a sterilization process by changing color. Chemical indicators or
The intense heat of flash sterilization can shorten the integrators can be used in flash sterilizers. They will change color
life of power equipment (drills and saws) and batteries. when the exposure or parameters have been met. The chemical
Frequently, when the flash cycle is complete, batteries indicators/integrators should be placed in each tray among the
are not immediately removed from the sterilizer; hence instruments with every cycle.
the batteries sit longer in the extreme heat than they Biological indicators (BI) monitor the adequacy of the
should. The condensation that is formed inside the power sterilization process and the destruction of microorganisms. They
equipment can increase the chance of corrosion and consist of an inoculated carrier (Geobacillus stearothermophilus
damage to the internal components, therefore an additional for steam sterilization) that provides a defined resistance to the
eight minute “drying time” may be added to help dry the sterilization process in which they will be used. Sterilizer operators
water droplets that have been created in the device. should verify that the date on the BI has not expired, and should
Precautions must be taken when items are loaded into be placed in the middle of the sterilizer above the drain. AAMI
the sterilizer to ensure that steam will contact all items to recommends that a biological test be performed at least weekly,
preferably every day that the sterilizer is used. A positive result
for growth would indicate that the sterilizer did not function
appropriately. The sterilizer must be taken out of service immedi-
ately and the instruments must be re-sterilized. In fact, all items that
were processed in that sterilizer since the last negative BI are
considered non-sterile. This is why documentation of all flash
sterilization cycles must be traceable to a patient.
AAMI and the Centers for Disease Control and Prevention
(CDC) warn against flash sterilizing of implantables. AAMI states
that “implantables should not be flash-sterilized. The possible
consequences to the patient from placing even a minimally
contaminated device in an essentially avascular environment and
leaving it there at the conclusion of the procedure are potentially
Printout tape from the sterilizer verifies that parameters severe.”3 In addition, implants should be quarantined until the
have been met. results of the BI are known.
56 MANAGING INFECTION CONTROL January 2009
When the sterilization cycle is completed, the contents all parameters have been met before releasing the load. The scrub
should be removed immediately for use. Items are considered nurse should visually inspect the chemical indicator for color change.
sterile when necessary conditions have been met during a Biological indicators need to be processed and read in a timely manner
sterilization process. The circulating nurse should assure that according to manufacturer’s instructions.
Attention should be made to avoid heat injuries when unloading
the sterilizer. The instrument(s) must be removed and transported
using aseptic technique. Transferring the sterilized item to the sterile
field is difficult without contaminating it. The scrub nurse needs to pay
attention to how they reach into the sterilizer to remove the contents
and not touch the edges of the sterilizer. The circulator should escort
the scrub nurse to the flash sterilizer eliminating traffic or opening
of doors from the inner core during transportation of the sterile
instruments. The risk of contamination increase if “transported
through areas where personnel are scrubbing or washing their hands,
creating splashing or aerosolization.”4 The work area should be
arranged so that it ensures direct delivery of sterilized items to point of
use without physical hazards and possible contamination.
Another concern of flash sterilization is being able to assure
Scrub nurses need to verify color change on chemical that all items are allowed to cool before using. To meet the
January 2009 MANAGING INFECTION CONTROL 57
demands of the surgical procedure, scrub nurses frequently not used on the procedure, the documentation must be
try to cool the instruments by immersing them in cool completed for that particular cycle. Accountability for each
sterile water or wrap in sterile wet towels. Depending on load must be maintained. Sterilization records are considered
the item, this cooling process can cause harm to the instru- legal documents and, since the length of time they must be
ment. For example, if attempting to cool autoclavable kept varies, each healthcare facility must develop record-
scopes too quickly, it can crack the lenses inside the scope. retention policies based upon state and local regulations and
Cooling power equipment (drills/saws) quickly can cause legal considerations.
more condensation to form on the inside. Most importantly,
the hot instruments can cause injury to the patient and/or Sterilizer Maintenance
physician. Depending on the thickness of the metal, the Sterilizer maintenance is important. Sediment screens
scrub nurse might think it is cool enough to use, but instead should be removed and cleaned daily because clogged strainers
it heats up in the surgeon’s hands or while on the patient. prevent air from being removed from the unit. Chamber
Some retractors are thick and the heat continues to leech interiors should be cleaned weekly with a mild detergent.
out during the case. Burns may not be noticed until the Note: Sterilizers must be allowed to cool for eight hours
retractor is removed from the incision site. We must before cleaning. Maintenance requirements differ depending
remember that while the patient is under anesthesia and on the model used, and the sterilizer manufacturer’s instruc-
unable to alert the staff to undesirable conditions, we must tions should always be followed.
act as their advocate and prevent these accidents from
happening. Let’s not forget the danger to the employees
themselves. When carrying hot and heavy instruments from
the flash sterilizer, poor body mechanics are frequently
used in holding the hot items out and away from their body
to prevent burning. These poor body mechanics lead to the
straining of the lower back and arms.
Documentation of the flash sterilization process should
be consistent with requirements for sterilizing wrapped
items. However, flash sterilized items require documentation
linking the patient. The following information should be
documented for each flash sterilization cycle:
Sterilizer number and sterilizer load number;
Sterilizer operator; Sediment screens need to be checked daily for
Chemical indicator; proper maintenance.
Contents of load (including BI if used);
Reason for flash sterilization; Ongoing Considerations
Initialed printout tape of cycle parameters. To flash or not to flash, that is the question. According to the
Association for periOperative Registered Nurses (AORN), it
Effective documentation ensures that the sterilization states that flash sterilization should be minimized. It should only
process is monitored as it occurs, that required cycle param- “be used in selected clinical situations and in a controlled
eters have been met, and that accountability is established. manner.”5 It should not be used as a substitute for not having
At the end of each day, each sterilizer should have complete enough instrumentation. Scheduling of cases in a manner that
documentation for each load. A common problem with does not require back-to-back usage of the same instrument trays
flash sterilization is incomplete documentation. Operating needs to be addressed. Managers who have budget constraints
room employees are overwhelmed with the other duties and often end up with insufficient instrument inventory. However,
tasks pertaining to their job and sterilization records take a purchasing of additional instruments to maintain the daily
low priority. Chemical control cards or integrators are lost; caseload should be a priority. Enforcing policies to have on
contents of the load are not documented and/or patient time arrivals of vendor pans, brought in the day before surgery,
information not included. Even if the instruments were is critical for providing the best care for the patient.
58 MANAGING INFECTION CONTROL January 2009
Reader Service No. 40
Alternatives need to be created for the doctor’s specials that are Carol Petro, RN, BSN, CRCST,
carried from the operating room of one hospital to another. Can we eval- is the clinical educator for
uate what is contained in these special instrument sets and provide them Clarian Health sterile processing
in one of our existing sets, so that they are sterile prior to the procedure? departments at Methodist Hospital,
Operating room personnel must maintain high standards of University Hospital and Riley
sterile technique. Every individual is accountable for their role in Hospital for Children in
infection control. Work practices need to ensure that proper Indianapolis. She has worked in
cleaning and decontamination is performed and that procedures the sterile processing department
are developed and followed in regard to flash sterilization. ✛ for two years and the surgery
department for 25 years. She has a
References Bachelor of Science Degree in Nursing from University of
1. ANSI/AAMI ST79:2006. Comprehensive Guide to Steam Sterilization and
Sterility Assurance in Health Care Facilities. Arlington, VA.2006, page 2-3. Indianapolis. She received her technical training as a
2. International Association of Healthcare Central Service and Materiel Certified Registered Central Service Technician (CRCST)
Management. Central Service Technical Manual. Seventh Edition. 2007. from IAHCSMM in 2006.
Point of Use Processing, chapter 14, page 269.
3. ANSI/AAMI ST79:2006. Comprehensive Guide to Steam Sterilization and Previous positions held at Clarian included Oral/
Sterility Assurance in Health Care Facilities. Arlington, VA.2006, page 3. Maxillofacial/Ophthalmology Specialty Coordinator from
4. ANSI/AAMI ST79:2006. Comprehensive Guide to Steam Sterilization and 1992 to 2001 and Special Projects Coordinator/SurgiNet
Sterility Assurance in Health Care Facilities. Arlington, VA.2006, page 2.
5. Association of PeriOperative Registered Nurses (AORN). Standards, Informatics Project Leader from 2001 to 2005. She may
Recommended Practices, and Guidelines. Denver, CO. 2007, page 675. be reached at firstname.lastname@example.org.
January 2009 MANAGING INFECTION CONTROL 59