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Article | December 31, 1994
Out of pack, top of mind
Keeping medical device directions outside of a sterilized package lets a healthcare professional read up before opening the package. Luther Medical's patented tray design holds scrolled instructions outside the pack for its catheters.
Among the most frequently used medical devices catheters are offered in a wide variety of lengths and diameters. Luther Medical a specialized manufacturer of catheters recently adopted new packaging that helps the healthcare provider make sure he/she selects the proper size and model for the patient's needs.
Especially when used in home care catheter packages always had to be opened to allow the healthcare professional to extract the DFU (Directions for Use) the required "manual" that describes the applications for a particular catheter model. Tustin CA-based Luther Medical was often told of the product and package waste when the wrong product is chosen. To minimize this and as part of an overall package redesign Luther worked with Plastofilm Industries (Wheaton IL) to devise a tray design that holds the DFU outside the sterile package so it can be examined without breaching the sterility of the package.
The design patented jointly by Luther and Plastofilm employs an open channel in the thermoformed tray that Luther eventually loads with a tightly scrolled DFU once the package is sealed. Originally this design change was developed for Luther's neonatal catheter for tiny babies; it has since been adopted for other catheters as well. Each tray is thermoformed from 25-mil sheetstock of Eastar(TM) PETG from Eastman Chemical a medical-grade PETG that's extruded by Pacur (Oshkosh WI). The trays are heat-sealed with printed Tyvek by DuPont (Wilmington DE).
"A lot of nurses told us that they were having difficulty selecting the right catheter for the right job" says Barbara Luther director of regulatory affairs. "It's very important for the nurse to understand the precautions and warnings that go with these catheters. So as we looked for an answer to making the DFU available without opening the package we also solved another problem."
Damage an issue
The 28-ga neonatal catheter is extremely thin approximately the width of four human hairs. To help minimize the possibility of the catheter kinking Luther inserts a tungsten wire inside the catheter as a stiffener and previously packed the four models in long packages. Each catheter is packed with a "luer" on the end that connects to the medication source. The device is used to infuse drugs like antibiotics or nutrients right into the patient's vein from a bag or container of solution.
To accommodate the luer the previous long packages allowed the product to move around. Damage caused by the product moving in the package wasn't a significant problem until Luther began shipping overseas by surface ship. That's when changing the package configuration also became important.
The new package design uses a deep draw cavity so the catheter itself can be coiled without a worry about kinking. Not only does this help prevent product damage it also results in a smaller more efficient package.
In conventional packages the multipanel DFU is folded and loaded inside the tray. While this means the DFU stays with the product until the time of use it also requires the package be opened for the DFU to be read. And the paper DFU can move around and create particles in the package.
The DFU channel
Ed Berger Plastofilm's representative on the West Coast and a Luther Medical engineer worked together to come up with the idea of rolling the DFU securing it and inserting it into a channel on the bottom of the tray.
This allows the nurse or other healthcare provider to remove the DFU from the channel and read it to determine whether this is the proper device for the patient-all before the package is opened. "If the person is a new user he or she needs to read the warnings and directions" Barbara Luther states. "If they're more experienced it gives them a chance to note that we've added some new references in the DFU to bring them up to speed. For example the DFU tells them what kind of priming volume is needed and the pump pressure virtually everything they need to know about how to use this product."
The creation of the thermoformed channel and the scrolling of the DFU were not easy to accomplish. "We didn't use any unusual equipment in this but there was a lot of handwork in making the molds" says Plastofilm project engineer Mike Moren. "We had to do a lot of fine-tuning to get the necessary undercuts to come out of our molds correctly without distorting the tray itself."
In the end the draw for the channel is deeper than the product cavity. So Plastofilm also molded in extra "feet" below the product cavity to add some stability to the part for stacking. As well it shifts the "load" from the product cavity to the DFU channel and the feet. This actually happened more by necessity than design Moren explains.
Holding product in place
Since the product is coiled in the tray the supplier added some extra "security seal points" in the top of the tray for the Tyvek lid to seal to. These extra seal surfaces near the center of the tray prevent the product from moving around inside the tray Luther says.
"Normally we'd get by using a friction fit or undercuts to hold the product in place" Moren says. "In this package we also use the Tyvek lidding to hold the product in place. So we added some sealing platforms inside the cavity. It's a little extra insurance that the product won't move around."
The whole process of design took about three months he says. The majority of that was in prototyping and mold design revisions to meet Luther's needs and to get the tray to form correctly.
"Plastofilm's engineers have worked with us on several difficult designs" Luther says. "They've developed some undercuts even they didn't know they could do. They represent one of our strongest vendor partnerships."
For example the depth of the DFU channel was dictated by the need to get the proper distribution of the PETG for undercuts in the channel. This extra depth provided another opportunity to Luther-a place to put a patient label in the pack.
Peel and stick label
The neonatal package was so well received that Luther decided to add the DFU channel to its dual-lumen and silicone catheters that are normally used for adults. For these packages Luther has added a peel and stick paper label that can be affixed to the patient's records when the product is used. The label is positioned inside the tray on one side of the cavity that makes up the DFU channel.
"We use this label only for the adult catheters" Barbara Luther says. "The label contains the product identification with all specifications including lot number. The nurse can affix the label right onto the patient's records. It's just another way to help make the nurse's job a little easier."
Luther's packages are all sterilized by gamma ray so PETG is about the only formable material that will retain clarity and strength after sterilizing. The clarity permits visual inspection of the package to ensure all components are properly loaded. While its engineers helped develop the DFU channel concept they also designed the machine that scrolls the DFU in their plant.
The machine includes a metal tube with a slot in it. One edge of the DFU is loaded into the slot and a motor engages to roll in the rest of the paper. The paper comes out in a nice tight scroll. While it's on the mandrell the scrolled DFU receives a stretch band of clear film to hold it tight. Then the DFU is removed from the mandrel and slipped into the channel of a package.
How nurses react
Since healthcare professionals have become accustomed to fanfolded inserts Luther had some concern about they would react to a scrolled insert. "We were assured that nurses are smart enough to reverse roll it to make it lay flat" Luther says. "Many nurses had told us they rarely read DFUs because they couldn't find them."
Luther sells through distributors that are enthusiastic that the packaging change is another great feature. "All together you can see the catheter all the components inside the package-that was important to us and the caregiver-and then we have a DFU that's easy to locate and understand" explains Luther. The package went through the U.S. Food & Drug Administration validation process last year.
The company has almost no concerns about the DFUs coming loose or separating from the tray. When the DFU is inserted into the channel it releases a bit to create its own tension against the sidewalls of the slot points out Ed Berger of Plastofilm. "If this package was subjected to treatment rigorous enough to work the DFU out the package itself is likely to have been breached" he says.
All of these improvements did come at a price as the tray cost has nearly doubled. But "in the long run I think it will cost-justify itself" says Barbara Luther. The company's earlier packaging was well under the 32% of product cost that's often common in medical devices. But she says it wasn't meeting the needs of the end user.
"This is more costly but we expect to dramatically reduce returns and damaged product credits" Barbara Luther concludes. "Even more important we want to provide our product in a form that makes it easy to use."
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