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Sterile Storage, Inventory Control, and Ensuring Items Are Delivered to the Point of Use Intact

One of the things I get to do for a living is to audit sterile processing department and perioperative sites for good practices. One of the things I do for free is participate in the Kilmer Innovations in Packaging – Last 100 Yards working group, a group that is developing support documents that will, hopefully, assist in ensuring that items delivered to the healthcare institution in a sterile state or rendered sterile in the course of processing them at the healthcare institution arrive at the point of use in a sterile, usable state. In both of these situations, I get to examine the issues typically found during SPD and materials management for storage and transport. Sometimes, I get to see great work. Sometimes, well, let’s discuss that a little.

Storage environment
Recent discussions on the AAMI Connect AAMI Members Discussion Group have centered on the issues of temperature and humidity in storage. Answers to these issues are provided by AAMI ST79:2017 and The Joint Commission EC 02.05.01, “Utility Systems.” Ultimately you refer back to ASHRAE 170, “Ventilation of Health Care Facilities” for required parameters. That’s a lot of references. When push comes to shove, the questions about the storage environment are:

  • Is the air moving in the right direction (positive or negative pressure)?
  • Is the temperature in a reasonable range?
  • Is the humidity in a reasonable range?

The tricky part with ASHRAE 170 is that you have to use the version that was current at the time your HVAC (heating/ventilation/air conditioning) system was installed or last updated. This allows older construction to be grandfathered in and limits the need for system modification on a nonemergency basis. And, as we all know, if it isn’t broken, you probably don’t need to fix it.

What is expected for sterile storage (or anywhere where sterile items are stored)? Here’s a table: [Insert Wilder-table]

Review of a range of products show that as long as the minimum temperature is above 68°F, the storage requirements of their IFU will be met.

How do you test this?

Airflow: Close all doors to the area being tested. Wait a minute or two to let things stabilize. Take a facial tissue, a cheap one, one that sacrifices comfort for lightness. Hold the tissue at the bottom of a door with a gap under it. If the tissue flutters in such a way that it appears to be being pushed under the door and out of the room, you have positive pressure (seriously). Measuring four air changes per hour should be left to the facility’s engineering staff, but they should be involved in this to ensure that they know it is what is needed. More is okay. Less is not.

Temperature: Take a calibrated thermometer and measure the temperature at a few locations in the room being tested. Or get a temperature datalogger to measure automatically over a period of time, preferably at least 24 hours measuring at least once per minute. Place it in with the sterile storage items. Read the results. Either you passed or you didn’t.

Humidity: Take a calibrated hygrometer and measure the temperature at a few locations in the room being tested. Or get a humidity datalogger to measure automatically over a period of time, preferably at least 24 hours measuring at least once per minute. Place it in with the sterile storage items. Read the results. Either you passed or you didn’t.

Why 24 hours? Because HVAC systems tend to cycle over that period and have limited ability to control conditions in any case. High traffic (peak work times) and the middle of the night are very different situations for them.

Storage
FIFO, Kanban, Crowding. Do Not Bend, Fold, Spindle, or Mutilate. Fun with Friction. Inspect before Using. What?

FIFO
First In, First Out. Use the oldest items first. Check expiration dates on items when picking a case. Restock goes to the rear of a bin so the older items move forward in it to ensure they get picked first.

Kanban
Kanban is a simple way of ensuring you don’t run out of stock. It involves placing a “Reorder Now” card in the storage bin ahead of the amount of items you will need until a restocking order can be received. When you reach the card, reorder. Where does it go in the bin? Your situation will vary depending upon how many items are normally used in a period of time and how long it takes to get a replacement order in. If deliveries are variable, as they are now during COVID, you need to consider a Just in Case system, not a Just in Time system. Why? With any shipping delays, which are common now, Just in Time easily becomes Just too Late.

Crowding/do not bend, fold, spindle, or mutilate/do not stack
Sterile-packaged items are delivered to or prepared at your facility in a certain state” not crushed, not bent or folded, not torn. Some items’ packaging doesn’t respond well to stacking. If a storage bin is overloaded, you can have these things happen, and the result can be that a sterile barrier is compromised. Or that you can’t do FIFO picks for cases. Or that the whole thing falls on the floor. Enough room for the items that are needed is almost as important as the items themselves. If you have limited space, it’s time to consult with a shelving manufacturer who has a better solution. Or to make sure you haven’t ordered too much of an item.

Fun with friction
Friction is a great thing if you are trying to start a campfire and don’t have any matches. It is not a good thing for sterile packaging. It leads to compromise of the sterile barrier. And you get to process it again with the OR screaming for it to be done now. Lift items off the shelf, don’t slide them. Place them in the case cart without sliding.

Inspect before using
The package must be intact before the item within is delivered to the sterile field. If it isn’t intact, it isn’t sterile either. You need another one or the patient can get an HAI. But it is better to know this before the patient is on the table, so inspection when picking a case is essential. As is a final check after delivery to the OR. A simple visual check is a useful way to ensure that the packaging is intact, both before the tray is unwrapped or the container is opened and after. Stopping a possible HAI is worth the time.

I know that all of this seems like common sense, but as we all know, common sense isn’t common. Let’s all do our part to make it more common!


Dr. Jonathan Wilder has worked with all thermal and chemical sterilization methods, as well as cleaning and disinfection methodologies, bringing his background in physical chemistry and surface physics to bear upon difficult problems in the field. He has been an active participant in U.S. and international standards development since 1998 through AAMI. As of January 2018, he is the cochair of the U.S. standards-making committee for hospital steam sterilizers.

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