FDA guidance and developing standards from ISO and AAMI/ANSI have shifted more attention to device and package designs that consider the needs of end-users and reduce the likelihood of human error.
At Cardinal Health, the usability of product and packaging is formally considered as human factors in design are captured and documented as part of a Design Control system, says Dan Penny, director of packaging engineering.
Cardinal focused on easy and consistent opening in developing a cost-effective bag for gowns, surgical kits, and other large disposable supplies. The goal was to improve performance compared with bags available in the market.
In development, Cardinal’s nurse consultants–experienced nurses employed by Cardinal–sought insights from end-users. “The nurse consultants are a captive resource we use regularly to get feed back from customers on changes to packaging. Depending on the scope of the project, we may start with the consultants and then do further interviews with focus groups to gather Voice of Customer,” Penny says.
Bags that claimed to be “easy open” were assembled and tested for tensile strength on a machine that duplicates the movement of a linear tear. The opening force required to open a variety of different structures was quantified.
On bags that have been in the field for years, nurses sometimes report they work great; other times they are very hard to open, Penny says.
“These complaints made sense when we started looking at the spread or standard deviation of the data, which correlated with the feedback we were getting. In some cases, the averages were all very similar, but with more data we started to see there was significantly more variability with some structures.”
Cardinal created quantitative data for a bag with an easy-open feel, specifying an ideal opening force and a window of acceptable opening force.
“This put us a step ahead and led us to the converter for material selection and design.” Cardinal collaborated with Amcor Flexibles to develop the DuraTear Film Bag, a vented polyethylene structure.
“We developed this material in an iterative process with Amcor to get the package material that gave us both the durability and the barrier we needed, and at the same time provided an easy-opening feature. There were several iterations of material development that went into that,” Penny says.
The notched bag features a low linear tear strength. Material design also had to address consistent opening, as nurses experience problems with tearing when they reposition their hands.
“Some of these bags are fairly large–we have a bag as large as 32 by 28 inches for larger surgical packs. Nurses have reported to us that if they start and stop they don’t get as clean an opening or can’t complete the tear. The opening feature had to reliably tear with the same ease and consistency,” he says.
The bag’s good contact clarity allows the user to see labeling delivered as an insert inside the bag, outside of the wrap. With on-demand insert printing, Cardinal reduces inventories, carrying one generic bag per size.
“We have 1000′s of different codes; we don’t want 1000′s of inventories of pre-printed bags. This allows us to do color-coding, and we use larger font sizes for critical label information such as size and protection level. Insert labeling has been a very manufacturing-friendly, cost-effective solution for us,” Penny says.
Used for Cardinal’s gown packaging and packaging of other large items, the bag combines necessary strength and resistance and sterile barrier, with easy opening.
“It’s a trade off. You need materials that provide abrasion, puncture, and flex-crack resistance, and enough strength to survive the distribution environment, created with a low notched tear strength in the machine direction so you can have the easy opening feature. The linear tear vented bag can be very cost effective, and still be perfectly functional.
“We feel that the best application of this bag is for larger bulky products such as surgical packs. And it is a cost-effective method of packaging when the product has a wrap to provide aseptic presentation.
“The feed back from the field has been positive,” Penny says.