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Alginates and Other Emerging Dressings for Diabetic Foot Ulcers

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Hi, my name is Cathy Milne. I am an adult nurse practitioner and board certified wound, ostomy, and continence nurse practitioner and my certification is CWOCN-AP through the Wound, Ostomy, and Continence Nursing Society. I practice in Bristol, Connecticut and my practice actually goes across the continuum I see patients in acute care setting. I see patients in an outpatient setting. I see patients in long-term care, assisted living, and I'll even make house calls for the truly homebound and work with home health agencies to get patients the best care that they can at home. 

Advanced wound care dressings are needed for all chronic and acute care wounds, especially when you think about the diabetic foot wound. You have to think about the pathophysiology that is associated with that diabetic foot wound. So a couple of things, number one, they are mostly neuropathic, and they can also be ischemic. So they can be neuroischemic also.

And so when you have a neuroischemic wound, you don't have good blood flow, plus the pathophysiology with the diabetes actually reduces blood flow through a number of mechanisms. So the long story short here is that you're going to have biofilm and bioburden on that wound. So you're going to have to address that. And you're also going to have a lot of inflammation. So you have to address inflammation.

So when you're thinking about dressings, you want to think about the pathophysiology. And then you want to start thinking about what dressings can go on there. And they're all going to be ... you have to use an advanced dressing.

So it's gonna also have to think about the exudate that may be coming off of that wound. And where that patient is. And then you figure out which advanced dressing, but you cannot not have an advanced dressing with the diabetic foot wound. 

There's so many dressings to think about when you're managing a diabetic foot wound, and you have to figure out what stage of healing they are in. So are you trying to debride that wound, in which case there are a number of dressings that can do things faster and some things that can do a little bit slower? Are you trying to manage infection? Are you trying to manage inflammation? So I use that TIMERS concept, so T for tissue, I for infection and inflammation and M for moisture balance, E for the edge effect. And so not only do we have traditional advanced wound care dressings that manage these issues that we see in the TIMERS, but we also have cellular and tissue-based products, which you would most likely use towards the end of that continuum, meaning your wound bed is clean, it's free of infection. you've reduced your biofilm as much as you possibly can, and then your wound bed is well-prepared to accept these advanced cellular and tissue-based products.

So when you're trying to figure out if you need to change the type of therapy you're giving, I think we all traditionally go on a wound measurement but there may be some difficulties with that and a lot depends on who is measuring and how much pressure maybe they're putting on a probe when they're exploring that wound because some people are not as forthright and feel confident enough really probing down. And so I think when we look at measurements that's really the standard. I think we really need to start thinking about technology. There are a number of devices out there that can tell us if we have a bioburden, how our blood flow is. So I think we need to start moving towards these advanced technologies. Unfortunately, these things are a little bit more expensive than most of our administrators really want to spend. So some of us are still in the more traditional wound measurement phase and some of us are more advanced. We really need to start pushing towards those advanced technologies because they give us better information earlier on, so we can act upon that.

When we start thinking about the alginates, they are a class all of in itself, and we have to think about how they are constructed and what are they really made of. So when you think about alginates, they're made of seaweed, but how they're constructed, meaning how they are physically constructed, because they can be woven, they can be carded. And so their manufacturing process can be different. So that can affect how much exudate the dressing can absorb. They can have additives in there, such as manuka honey or silver. Or you can have a collagen put in in some of these alginates, so you really need to know what kind of alginate you're really dealing with. 

In addition, we have to think about the type of alginate that's in there. So there can be calcium alginates, there can be sodium alginates, there can be calcium sodium alginates, and so they work a little bit differently when placed on the wound bed. And then the type of alginate. So there's M-blocks and G-blocks. Now the G-blocks do not disperse, and so they hold not as much as the M-block type of alginates, but you can get them out of the wound really easily. If you are using an M-block, alginate, and you have to ask your rep what kind of alginate you have or call the company's medical science liaison who can tell you some of these details because it's not usually on the package or in the product insert. The M-blocks actually disperse really well and turn into a gel and so they are less painful when they are removed from the patient rather as compared to the G-block alginates.

So, you have to match your patient characteristics to the type of alginate that you have available because it's unlikely that your system will carry three or four different types of alginate. They will usually have one brand. So you need to know what the characteristics of that brand is, how it's constructed, and when it's appropriate to put it on that case.

So, I do use alginates in my practice in managing the diabetic foot wounds. I use a number of other products too, but I will use alginates  when I have a little bit of bleeding and the patient gets a little upset about that because some of the M-block type of alginates can actually help reduce that bleeding.

They help clot because the calcium in the M-block dressings and to a lesser extent the G-block calcium alginates will actually impact the clotting cascade so you can actually clot the wound. So if your patient is suddenly having a little blood in the wound with the formation of angiogenesis or early angiogenesis and they're staining their socks and they're upset, certainly using that is helpful. But also we also see some anti-inflammatory effects. The calcium alginates actually will improve or reduce a little bit of the inflammation.

Once you have the macrophages in there responding to the issues in the wound with bioburden, the alginates actually will help tamp down some of that inflammatory response. In addition, what they're going to do is trap exudate and trap bacteria and some of the inflammatory markers. So if you have that in the wound, that is where you're going to want to think about using a calcium alginate.

I think we have to remember that in the U.S., both alginates and gelling fibers, or also the trade name would be a hydrofiber, are actually under the same category in terms of reimbursement. And they do act very differently. The alginates will actually do lateral wicking, and the gelling fibers do vertical wicking.

So when you think about using an advanced dressing, especially in the diabetic patient, you may want to think about how you want to protect that periwound. If there is maceration, you're going to actually have more bacteria and eventually have more and bigger problems with your diabetic foot.

So thank you very much. I'll hopefully that'll be your tip for the day. 

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, HMP Global, its affiliates, or subsidiary companies.