“If we don’t come up with a credible, logical way that we can characterize the various materials, features, performance, durability, etc., of cushions, then our future is going to be one where the payors are going to cut costs, the providers are going to pick the cheapest (products), the clinicians are going to have little access, and the end-users are going to suffer.”
So says Dave McCausland, senior VP of planning & government affairs, The ROHO Group, in explaining why he and ROHO are involved in the ongoing Cushion Characterization Project.
At the International Seating Symposium (ISS) in March, McCausland and Mark Greig, VP of research & development, Sunrise Medical, presented an update on this project, which McCausland says began in 2004 with contributions not just from ROHO and Sunrise, but also from Otto Bock, researchers and industry experts including Stephen Sprigle and Evan Call.
Greig says enabling funding sources to better understand and define performance requirements in cushions is one of the project’s primary goals, but he adds, “It has other benefits, too. This kind of information could benefit clinicians in being able to understand how to apply specific cushions to the needs of specific individuals by understanding the performance of the cushions better. And I think it can provide a much more holistic view of the cushion. Part of the intent of the cushion characterization was to focus on skin integrity and pressure management, but also other aspects of the cushion, such as stability and positioning. And by providing data on a lot of those different aspects, the idea was that clinicians could make better decisions on how to apply products.”
Seating as a Science
Sunrise Medical, Greig explains, has been working for years on “the use of science and the design and prescription of cushions. What we did was dissect the design of cushions to say how cushions can be made, or design techniques that could be used to make cushions in order to have them function and perform to different levels and different standards. It encapsulated things like hydrostatic pressure relief, cushion segmentation, a lot of those design aspects and techniques.”
But Greig says a component that was missing “was the ability to verify that those design techniques worked as intended. So theoretically, the design techniques should work, and through some clinical experience, we knew that they did. (But) there wasn’t this means of actually testing the performance of those design techniques to ensure that the cushion did perform well.”
McCausland, meanwhile, had been working on the use of laboratory testing techniques to assess the performance of cushions.
“And at that point in time,” Greig says, “Dave and I put our heads together and said maybe we can serve a couple of purposes here if we work together on developing or furthering test standards for cushions.”
From McCausland’s policy and funding perspective, the need for the project can be traced to 2004, when Medicare established new medical policy for seating.
“It goes back to that moment when we realized that left to their own devices, regulators were going to either fail to establish good definitions or requirements for what a product needed to do in order to (qualify) for a classification, or they were just not going to have anything at all,” McCausland says.
He points to ongoing Medicare actions as proof.
“You’ve got all kinds of payors trying to find out ways to cut their costs,” McCausland says. “Medicare is doing it through competitive bidding. This competitive bidding system bids codes. The only way you can win is to offer the lowest possible price. So (Medicare) says, ‘OK, provider, I want you to bid for this code.’
“If the provider wants to win, they’re going to go to Medicare’s own database, and they’re going to identify all the products that are assigned to that code by Medicare. Then they’re going to look at their acquisition costs for each one, and they’re going to bid the cheapest. Whether that product actually is equivalent in performance and durability to the other products on the list, who knows? But according to the government, they’re all under the same code.”
McCausland says there are currently more than a thousand products in the adjustable seating category, “and I guarantee they’re not all the same as far as clinically relevant characteristics.
“We had to do something because the government has created a categorization system for seating – and it’s not just seating, but seating is an example – which does not create homogenous groups of products relative to their performance and their efficacy. And in trying to drive down costs, the beneficiary’s going to be the one left at risk.”
The Project’s Take on Testing
The Cushion Characterization Project seeks to, among other things, provide for testing that is more indicative of how cushions are used in the real world.
Of the current immersion test for cushions, Greig says, “What we saw was that the immersion piece was a poor indicator of the types of things that we should be looking at, which is pressure management.”
In addition to immersion, the project would look at envelopment as well as magnitude, which McCausland describes as “how much difference there is in the load being applied across. The perfect scenario is you have very low pressures distributed across the entire contact area, and those pressures are almost identical across the whole area.”
“We know,” McCausland says, “that ultimately we have skin breakdown because oxygen- and nutrient-enriched blood flow is eliminated or dramatically reduced to a particular area of the body. If we have any part of the body that’s not getting oxygen- and nutrient-enriched blood, that tissue will die. That’s the problem.
“There are all kinds of other things we have to take into consideration, such as how are we cutting off that blood flow? Does the blood flow have oxygen and nutrients? What’s the overall strength of the individual’s skin, because if you have a very low-tensile strength of the skin, they could be more susceptible to breakdown. Fundamentally, you have to have blood flow there to keep it healthy, and it’s got to have the nutrients and oxygen.”
A common cause of reduced or eliminated blood flow, McCausland says, happens through “a deformation process, which pinches off the capillary flow at a particular point. So if you think about it from a seated standpoint, when we sit down, basically 70 percent of the weight of our body is literally being balanced by two bones, your ischial tuberosities. You’ve got these two pointy bones in your pelvis that are aimed down toward that cushion, and you’ve got 70 percent of your weight balanced on those. Ultimately, it’s very possible that if you don’t try to redistribute that load more evenly across the whole pelvis, those two bones are going to continue to press down, and you’re going to pinch off the blood flow to the tissue directly beneath those bones. And that’s going to create a wound, and now you’ve got a problem.”
Envelopment, therefore “looks at how effective is the product at trying to distribute the load evenly across the entire contact area, as opposed to on those two bones.”
Says Greig, “The other facet to this testing is also to look at a cushion’s ability to manage pressure under different circumstances. The current test just looks at immersion and really only from the weight of one individual and the shape of one individual, and from an inadequate perspective because the indenture is not very representative of a human form. What we’re trying to do is look at what the pressures are, what the envelopments are for people of different sizes, shapes, different weights and different orientations of the person’s form as they sit into the cushion, to see how cushions are able to accommodate those kinds of differences. Those kinds of differences are the things that clinicians see every day. How does that cushion perform with someone who’s got a pelvic obliquity? How can they accommodate that, and once they accommodate that, how well does that cushion perform under those circumstances?”
McCausland says the project advocates cushion testing that more accurately encompasses the types of scenarios seen by clinicians and providers, including asymmetrical postures, client weight gains or losses, and different body types.
Of the current seat cushion testing requirements, McCausland says, “I can make a cushion out of concrete that has a 2” wide slit that I put foam in and it will pass the test. It’s basically a horizontal bar – to simulate from the left trochanter to the right trochanter – that they apply a weight to, and they want to see if that bar will immerse 40mm into the cushion. If it does, it passes as a skin protection cushion. If it doesn’t, it’s not a skin protection cushion. That’s it.
“This bar is only about 2″ wide, so (the test) is not looking at the characteristics of anything other than on this particular bar, and all it’s looking at is immersion. What’s fascinating is that in the research we’ve done on these laboratory tests, immersion is a good thing to consider. But if this were a poker game, immersion is kind of like your ante. It gets you into the game, but ultimately immersion doesn’t tell you the much more important, clinically relevant features that you need to look at in a cushion for skin protection relative to magnitude, relative to envelopment, relative to off-loading. You can have a product that immerses very deeply that gives very, very poor results for magnitude, envelopment, off-loading. You can have a product that barely even immerses 40mm, but it does pretty good at envelopment and off-loading. Immersion is kind of a pass/fail, but there are a lot of other factors to consider than that. That’s what our testing really looks at.”
The testing would also examine the cushion’s ability to stabilize and maintain stability, Greig says: “How well does the cushion provide stability to keep someone from moving forward and going into a sacral sit? How well does it keep them in an upright position? We developed a test for that that we think mimics what the forces are that would drive someone to become unstable in that forward position.
“And then we looked at it from a lateral perspective, so if someone’s sitting upright and there’s a destabilizing force laterally, left to right, how well does that cushion either prevent that person from leaning over or tilting over, and if they do lean or tilt over, is there a restabilizing force that provides an ability for them to go back into an upright position? Or does the cushion just allow them to flop over to the side and not provide that restabilizing force? So we looked at it both from the forward position and that lateral lean position, and have developed tests for both of those that we think are in a state very comparable to our skin integrity state, as far as validating those tests and making sure that they’re clinically relevant tests, as well.”
The Next Steps
“A lot of this work,” Greig says, “was born out of efforts by multiple groups. It wasn’t just Sunrise and ROHO. We just felt that at the time, it had stagnated and needed to be pushed forward to the point that the standards were valid tests, and in fact that they mentioned clinically relevant aspects of cushions. So we feel that we’ve taken it to that point.”
After ISS, McCausland says, “There was an ISO meeting where our information was presented, and right now there’s discussion of this being included in at least two standards and perhaps more.”
He admits the process has been long and arduous, but knows what success would look like: “If we take all the time and expense that we put into this, and hand it off to an international group to utilize universally.”
This is an extended online version of a story that appeared in the May 2011 issue of Mobility Management.