While random wet packs will happen to even the most quality-driven, conscientious SPDs, frequent occurrences tend to signal a bigger problem – one that requires prompt, proactive detective work to determine the cause and appropriate resolution (coupled with a hearty dose of staff training to reduce the risk of repeat occurrences).

Because numerous factors can contribute to wet packs, and because just as many approaches can help prevent them, Healthcare Purchasing Newsasked sterilization accessory vendors to weigh in on the subject and help sterile processing professionals make better sense of wet packs, while, hopefully, also helping to make frequent occurrences a thing of the past.

Case Medical’s laporoscopic basic set

In my experience, the top mistakes leading to wet packs in SPD are putting wet instruments into the trays prior to sterilization. This is often the case when staff is pressured to rapidly process sets. The increased use of flash sterilization cycles leads to wet packs. Wet packs are also due to inadequate dry time in the autoclave even for terminal sterilization. Wet packs can occur when sets are removed from the sterilizer without adequate cool down which can cause condensation and in turn produce wet packs. Poor steam quality, poor maintenance of autoclave and older sterilizers also contribute. Inadequate drying of instruments in the washer/decontaminators can also lead to assembling wet loads. Avoiding wet packs may not be a top priority in SPD as it may be caused by many factors and the individual technician may be trained to look at only one aspect of the job.

Each of these can contribute to wet packs:

• Placing wet instruments in sets (instruments should be completely dry)

• Overloading trays

• Too much metal mass placed in a set

• Inadequate or inappropriate wicking materials used as a packaging aid

• Inappropriate loading of the sterilizer

• Inappropriate or overuse of plastic trays (the design of many are prone to moisture retention)

• Use of non-absorbent packaging materials

• Improper backpacking techniques

• Use of too much multi-layer packaging

Genesis case by Cardinal

Load size, inappropriate set configuration, poor quality steam supply issues and cooling too rapidly are the most common mistakes that can result in residual water after processing. Excessive condensation created during the cycle is difficult to dry in normal dry times, and cooling too quickly after the cycle can result in remaining condensation or even re-forming condensation -- all leading to wet sets.

—  Sue Christensen, Senior Market Manager, V. Mueller Genesis Containers

I believe the number one factor is poor technique by staff. Most wet packs can be traced to improper/inconsistent technique! Other causes include:

• Insufficient drying time

• A wet product prior to packaging

• Excessively large instruments being sterilized

• Instrument sets not being permitted to cool and equilibrate to room temperature

• Instruments cooler than room temperature at start of sterilization process

• Cool down process interrupted or too brief

•Weight & density of set too great

• "Wet steam"

• Re-condensation

• Blocked filter areas

• Sterilizer malfunction

• Sterilization container too small for instrument set

• Defective vacuum drying system

Aesculap Rigid container system product example

A lack of understanding of "how" the sterilization system works will prevent the SPD technician from being able to resolve the "why" it is not working properly. When the expected result is not achieved, assume nothing is working correctly and re-check everything. Some starting check points to help identify and resolve the problem include: are AAMI guidelines being followed; was it a dry load going into the sterilizer? Have there been any recent changes in the SPD (something new or recently "fixed")?; Has the set weight or packaging changed recently? Was the cart loaded improperly (with heavier sets on top of lighter ones?) What time of day did the wet pack occur? Was the exposure time accurate for the load? Were there changes in steam quality?

Through continuing education, proper training and super, careful selection and use of packaging materials and equipment, and adherence to manufacturers’ recommendations of use.

Through knowledge and training. The importance of SPD technician training and certification cannot be stressed enough. It is critical the SPD technician is viewed as a healthcare professional by the hospital and proper training and certification is encouraged. Better set organization is also important. Sets get overloaded by continuously adding instruments here and there without ever monitoring their usage. Before you know it, you have way too many instruments in the tray and some are hardly being used. Reduce set density and weight by monitoring instrument usage. A computerized instrument tracking system can be very helpful in monitoring set lists.

Quality controls, including a visual check for moisture, needs to be incorporated into prep and pack procedures. All instruments should be dry when placed into trays. If needed staff should be encouraged to dry wet instruments before assembly into the trays. Secondarily, staff should be given adequate time to process sets. More dry time may be required. Cracking the door of the autoclave helps tominimize the potential for condensate formation. Staff should allow for adequate time to fully cool down loads after sterilization before placing into service or storage. Finding more efficient ways of processing sets instead of flash sterilization or processing with abbreviated dry time. Staff needs to be more aware of sterilizer malfunctions and the importance of preventative maintenance. Routine checks of steam quality should be established. Staff should be encouraged to report all findings including wet packs and wet instruments to management.

Through ongoing staff training and immediate trouble shooting of any and all wet pack situations. When a wet pack issue is resolved, immediately educate staff on the resolution and treat each occurrence and resolution as a learning opportunity in order to reinforce proper technique in the future. Routine maintenance of sterilizers is also essential.

The personnel in SPD have a terrific challenge of processing myriad instrumentation and materials every day at non-stop paces and are often short-staffed. ‘Through-put’ can often overwhelm the attention to detail sometimes needed on a per-set basis.

With today’s high volume of heavy orthopedic sets, overloading containers is easy to do. It is easy to understand the resistance in SPD to breaking the heavy sets into multiple smaller, less dense sets. Change can be hard, and sometimes wet packs can be elusive -- making the need to reduce the weight or break up sets seem less urgent until a real problem arises and affects the surgical schedule.

Wet Packs can occur randomly for many reasons. Even with a well educated staff, it can be quite a challenge to trouble shoot the problem and come to a resolution. With the fast pace of OR’s today, infrequent and/or random wet packs can sometimes be "lost in the shuffle" and not addressed until the issue becomes severe. It is time consuming to adequately trouble shoot the problem and it requires thorough research, initiative, follow through and co-operation from the OR to successfully resolve the issue—many times SPD personnel may "give up" before the problem is resolved and just hope that the event does not occur.

I believe numerous factors are at the root of the problem: lack of resources and good management and supervision, poor quality assurance processes; work-related stress and pressure for fast turnarounds, staff complacency; and the design and materials of certain containment devices used (such as plastics).

The personnel in SPD have a terrific challenge of processing myriad
instrumentation and materials every day at non-stop paces and are often short-staffed. ‘Through-put’ can often overwhelm the attention to detail sometimes needed on a per-set basis.  

With today’s high volume of heavy orthopedic sets, overloading containers is easy to do. It is easy to understand the resistance in SPD to breaking the heavy sets into multiple smaller, less dense sets. Change can be hard, and sometimes wet packs can be elusive -- making the need to reduce the weight or break up sets seem less urgent until a real problem arises and affects the surgical schedule.

—  Sue Christensen, Senior Market Manager, V. Mueller Genesis Containers

Staff is rushed to process sets. More education is required to understand why wet packs pose such a problem as well as staff taking responsibility and personal pride in the job. Staff needs to be aware that any moisture in the container is considered not sterile unless it is for flashing for immediate use. Some vendors have instructed SPD staff to believe that moisture within a rigid container is sterile. This is not the case. Many loaner trays provided by major medical manufacturers are made of polymeric materials, which are not highly perforated, densely packed and then wrapped with polypropylene wrappers may not be the choice of the SPD department.

It all depends on proper use. That said, wraps are more prone to tearing and all wraps are not created equally. Some wraps may provide better wicking, which can facilitate drying, while some polypropylene wraps are more prone to moisture retention. Container devices provide better protection, but whether they will facilitate better drying is contingent upon material composition (aluminum has superior heat conductivity, which usually provides greater and more rapid thermal transfer, and it maintains heat longer, which also facilitates more thorough drying). Aluminum is alsodurable and won’t crack, so it’s more cost-effective in the long run. As with sterilization wrap, containers must be used in accordance with manufacturer instructions – and they may not be compatible with all sterilization methods.

Theoretically, the occurrence of wet packs should not vary between wrapped and rigid; however, rigid sterilization container systems vary by manufacturer and some systems have a lower occurrence of wet packs than others. Since the metal mass within the sterilizer itself can lead to wet packs in some cases, that may be a drawback for some container systems.

Both wrapped items and rigid containers can lend to wet packs, but wet pack issues are more easily identified when using rigid containers. Rigid containers are less forgiving than more porous materials, and – because they do not absorb moisture – users can more easily identify problems with wet steam, over-packing or quick-cooling conditions. Wrapped items have more have time to breathe and dry prior to the point of use – making it more difficult for users to identify root causes of the problems.

Rigid containers provides critical processing information that alternative wrappers do not. While the conditions they are subject to are always changing, the physical properties of rigid containers do not change – lending to greater sterility assurance. In essence, the container can communicate a problem somewhere in the sterilization process that would have otherwise gone undetected with conventional wrappers.

Wet packs are more prevalent in wrapped packs because most wrap used is a plastic material. Many of the trays that are wrapped are manufactured from autoclavable plastic materials or stainless steel. They do not have the thermal conductivity necessary for heat transfer. Rigid containers that are made from anodized aluminum with aluminum inserts provide the best thermal conductivity. In fact, as a material, aluminum is highly thermal conductive, more than 40 times more conductive than plastic and 10 times more conductive than stainless steel. Another factor is the degree of perforations of the inner trays to be wrapped and the perforations in the vents of the rigid container. For example, perforated bottom containers provide for better drying especially for heavy loads.

Making blanket statements are unfair, since wet sets are dependent on the overall process and instrument load rather than the packaging system. Rigid containers, however, add the consideration of container system weight. Lightweight aluminum container systems are less prone to wet sets than heavy aluminum container systems.

In order to realize all of the benefits of rigid containers, users should consult with the manufacturer of their systems to better understand manufacturer recommendations and why they are making them.

SPDs need to visually inspect each set prior to sterilization to ensure that there is no moisture on instruments to be packaged. SPDs should be encouraged to use trays and containers that are designed to provide maximum thermal conductivity. They should also find ways to work with the OR to minimize flashing or utilize a sealed container designed for flash sterilization which would provide them with a dryer outcome and comply with current standards and recommended practices.

Become the Sherlock Holmes of your SPD. Think about what is going on inside the sterilizer and become the detective. Continue to check everything. One of the quickest ways to resolve a wet set issue is to add a wicking material to the bottom of the tray (refer to AAMI ST79 Section 8.4.5 regarding the use of tray liners).

When selecting a rigid container vendor, consider the following points:

Weight of Container System: This is so important. A full-size container can weigh more than 10 lbs and that can differ according to vendor. Following the AAMI ST79 guidelines of 25-lb. total set weight, that leaves 15 lbs for instrument load. Selecting a lightweight container vendor with a broad portfolio is also extremely important.

In-service training: Knowledge is key. Today, SPD’s are being stretched to the breaking point, and a "do more with less" mentalityleads to a greater reliance on vendor service. The customer must be able to leverage the vendor’s sterilization experience to address their issues.

Instrument set organization: Weight is not the only factor. Also consider how the instruments and weight are distributed. The customer must be able to leverage the vendor’s instrument set care and handling experience to their set configuration.

Reduced set weight is important to avoid wet packs as dense sets are more difficult to dry. However, the issue of weight is more related to ergonomics and the safety of staff lifting the tray. If the instrumentation is properly organized in the tray and not densely packed the outcome would be greatly improved. Vendors need to provide adequate and truthful information to their users and follow AAMI and AORN standards. SPDs should be encouraged to question vendors and ask for documentation in wiriting. Set dryness should be demonstrated and should be one of the parameters for acceptance. Communication channels should be developed between SPD and their vendors as well as purchasing to address the issues related to set weight, wet packs and the choice of tray systems.

SPDs should ask for the general history of wet packs for the specific vendor product and should also carefully trial the product before purchasing it. The trial should include challenging the product with  a variety of sets that have different weights, instrument configurations and density/complexity of instruments.