The Rigid Container Story: Looking Back to the Future

June 1, 2002

hinsidecen.gif (3062 bytes)

The Rigid Container Story: Looking Back to the Future

By Bryant C. Broder, CSPDT, ACSP

containers were first developed in Tuttlingen, Germany in the mid-1890s. These
original containers were made of stainless steel, but chrome-plated containers
(in response to the needs of military hospitals and aid stations) had become the
container of choice by the early 1900s. The main function of these early
containers was to transport sterile instruments and dressings. In that era it
was not unusual for sterile supplies to be kept in a few containers for an
entire day's operating schedule. At about this time the first steam sterilizer
was created: the "Schimmelbus." Steam and container working as one
proved to be the most effective sterilization method for the operating room at
the beginning of the 20th century.

It wasn't until the early 1930s when reusable filters were introduced,
replacing existing valves and sliding vents. Rubber gaskets were added shortly
thereafter to ensure a more effective seal between the lid and container bottom.
In the 1960s anodized aluminum containers were introduced, providing optimal
heat transfer properties. The lightweight anodized aluminum construction allowed
for easy handling and stacking. As technology advanced, disposable non-woven
filters replaced textile filters within containers as a more secure barrier.

At the Association of Operating Room Nurses Congress in 1980, the concept of
"rigid packaging for sterilization" was introduced in the United
States. This new and exciting concept positioned itself directly opposite the
traditional wrap. The paper or cloth packaging originally employed for
instrument sets was challenged for the first time. Several issues emerged: micro
tears along paper edges, sterility during transport and excessive moistening of
the sets (due to the limited drying capacity of the material). Hospital
management became increasingly concerned about the high costs associated with
disposable paper sterilization wraps.

With time, sterilization containers gained the confidence of hospital
professionals. They are both durable and cost-effective, aid in set organization
and they tend to protect instruments better than wraps. There are dozens of
different container sizes and shapes to accommodate most commonly used
instruments. From instruments to scopes to drills to cameras, varying container
sizes seem to offer a viable alternative to wrap. Yet, with all of the recent
popularity and all of the history, questions still remain. "Are containers
safe?" "Are they really cost-effective?" And, "What
container system is best for me?"

First, let's examine what we know about our sterilization needs:

  • Safe, effective and reproducible sterilization of equipment is a critical
    component of patient care in today's operating room.
  • The supply of sterile equipment places high demands on quality management
    regarding sterility, hygiene and infection prophylaxis in hospitals.
  • Sterilization of instruments and equipment should be cost-effective.
  • Handling of sterile equipment should be simple, fast and safe.

The Safety Issue

When considering issues related to safety and containers, familiarity with
the manufacturer's sterilization validation studies is paramount. Sterilization
validation is a test conducted by the manufacturer that demonstrates the
sterility of container contents under defined parameters. The manufacturer
should be able to provide data proving that instrument sets can be sterilized in
their containers -- including information about load weight, type of process and
length of cycle. The manufacturer should also be able to provide a copy of its
FDA-approved 510(k) clearance as a Class II device. If a container will be
stored for an extended period before use, make sure to find out what shelf-life
documentation the container manufacturer can provide.

Based on the history of the product, safety-relevant design features must be
incorporated into the construction of the system. Relevant tests and validation
procedures must confirm safety aspects, especially the all-important microbial
safety of a container.

Some points to ponder:

  • Make sure the bottom and lid secures the sterilized goods against
    mechanical damage and thereby against recontamination after sterilization
    during transport and storage.
  • Develop a "worst case" limit at your institution for set load.
    This may be based on the manufacturer's recommendations or your own
  • The container design allows it to stay germproof after sterilization,
    during transport and during storage. Below are three basic requirements of
    the filtering system:

1. Change of atmosphere during the steam sterilization phase. Physical
requirements: air and steam must pass with a low flow resistance.

2. Cooling-down phase outside the sterilizer. Physical requirements: hot air
inside the container cools down, non-sterile air will be sucked into the
container, which must enter the container without contaminating the contents.
During the cool-down phase a huge volume of air has to be filtered back out.

3. Transport and storage phase. Physical requirements: under load and during
transport, due to atmospheric pressure differences, there is a pressure
compensation and therefore an exchange of a small volume of air. The filtering
system must allow this without allowing contamination. During transport there
are vibrations, and there is a rapid change of volume. The filter must work
efficiently and effectively during transport.

Assuming the validation process is satisfactory and meets all FDA
requirements provided to you by the manufacturer, the next logical question is:
"Is 'containerizing' cost-effective?"

The Cost Issue

The initial cost to the capital budget regarding the process of converting to
containers can be overwhelming, and this has prevented many institutions from
adopting the technology. If a large capital-budget expenditure is a concern,
some manufacturers offer monthly payment programs designed to move containers
into the hospital's operating budget. Even in this situation, it may be
difficult to justify the container expense to management. When making such an
investment, one must consider the long-term financial return. Containers save
money mainly by lowering expenses associated with wrap, but for some sets this
savings may not be enough to justify the container investment.

Consider the "soft cost" savings of containers as well:

1. Lower risk of instrument damage, lower risk of loss

2. Excellent storage space utilization (stacking of sets)

3. More efficient transfer from facility to facility

4. Fewer packaging material integrity breaches

5. Easier back-table setup in the operating room

The first step to analyzing the costs associated with containers is to look
at the facility's usage of high-volume sets. Some hospitals require that an
investment such as this return savings equal to the acquisition price within a
set period, known as the "payback" period. This period will vary based
on the financial models used at your institution, but many use an 18-month to
two-year period for payback to justify an expense. To calculate a simple payback
for your set, use the following formula: Cost of container and lid (number of
times a set is used per month) multiplied by the cost of wrap, tape and
indicators minus the cost of the container filter and lock. The resulting number
is the number of months that it will take to pay back that initial investment.
Many additional variables can be added, and of course you may wish to use
different measures than payback.

The only question remaining is: "Which container system should I

Choosing a Vendor

There are a number of manufacturers in the container market, making for
healthy competition among issues of technology and cost control. However, if you
do your homework, you may find that some vendors stand out from the others.
Consider these factors when choosing a container vendor:

  • Only work with a vendor that can produce FDA 510(k) Class II clearance.
  • Make sure their sterilization validations included very dense and
    difficult loads (worst case scenario) as well as difficult mechanical
    components (like motors).
  • Consider the vendor's reputation within the industry (tenure, quality and

Considering the above points should help you make a confident decision
regarding sterilization needs for your hospital. The future in sterilization is
bright, and the innovation and production of visionary methods that surround
this industry continues to advance the central service/sterile processing

Bryant C. Broder, CSPDT, ACSP, is manager of surgery processing at Saint
Mary's Mercy Medical Center in Grand Rapids, Mich. and president of the American
Society for Healthcare Central Service Professionals (ASHCSP). The author wishes
to thank John Cox and Jeff Smith from AESCULAP for providing information for
this article.