Section: CME Category: Wound Care

A Biophysical Approach for Healing Chronic Wounds

Naren Gupta, MD, PhD

Naren Gupta, MD, PhD delivers a comprehensive overview of compression therapy for chronic lower extremity wounds. Dr Gupta discusses the different types of compression currently available and advantages and disadvantages of each.

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Goals and Objectives
  1. Identify the basic components of treatment for chronic lower extremity wounds
  2. Identify which chronic lower extremity wounds need compression therapy
  3. Understand Starling Forces and how they differ in normal fluid exchange and chronic venous insufficiency
  4. Discuss the different types of compression therapy available and the advantages and disadvantages of each.
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    PRESENT e-Learning Systems is approved by the Council on Podiatric Medical Education as a provider of continuing education in podiatric medicine. PRESENT e-Learning Systems has approved this activity for a maximum of 0.5 continuing education contact hours

    Release Date: 03/16/2018 Expiration Date: 12/31/2020

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    Naren Gupta has nothing to disclose.

  • Lecture Transcript
  • Initiated the role of compression therapy regiment intermittent and pneumatic compression therapy for managing chronic wounds above and beyond even venous insufficiency wound. So we view a very important component of management of lower extremity wounds and pathologies. And so we’ve asked Dr. Naren Gupta to come to speak to us about this very important biophysical modality that we are incorporating into our wound care protocols more and more frequently. Dr. Gupta is a vascular surgeon. He trained at Emory University in Atlanta. Now, he’s practicing at the Brigham and Women’s Hospital as well as the Boston VA Center in West Roxbury. So let’s get a new overview of compression therapy for diabetic and lower extremity problems. So let’s welcome Dr. Gupta.

    Dr. Naren Gupta: I’d like to thank the summit organizers for this. For me, it’s a unique opportunity to talk to a podiatrist before they’re fully formed. I saw the previous two lectures and it really struck me how practical the talks were and I’m going to strive to be as practical as possible. I want to address a couple of questions. I think that it’s strange. When I look at foot wounds, I think that I’ll take care of the blood supply but I hope we have a good podiatrist. I’m lucky to say I have a great podiatrist that I work with, Charlie Foster. I call him the guru of the feet. So I’m always happy to come and talk to his residence. The topic that I’m dealing with is inflicted with a lack of randomized controlled trials. So I have tried to incorporate guidelines from AAHRQ, that’s the American Healthcare Research for Quality, and its Canadian counterparts, as well as some counterparts from England, and I’ve tried to keep all of these guidelines in the last year or two. So chronic lower extremity wounds, the risk factors that this talk is going to deal with is predominantly chronic venous insufficiency, lymphedema with the component of diabetes and of course peripheral vascular disease. The average duration of these wounds is a year and 60 to 70% recur. Most of the costs are actually in the recurrence and they take up 2 to 3% of the entire healthcare budgets of countries not just America. This is the same in Canada, in England. This is actually from the British Medical Center. These are numbers with billions in B. The basic components of treatment that everyone agrees on is optimum moisture balance, restoration of blood flow, prevent infection, debridement, protection from pressure and injury, and the part that’s interesting to this talk, compression therapy. So the biophysical component that I call treatment is compression therapy. And the caveat is, before you put compression on, you have to make sure that you don’t have to restore blood flow. So which wounds need compression? If you’re looking at a wound that’s painful, red, swollen, pruritis, it has scaling and discharge and it has a phenomenon called lipodermatosclerosis which is fibrosis and pigmentation of the skin. And it’s more in the leg than in the foot and you know you’re dealing with chronic venous insufficiency. Another word that’s used for this ulcer is venous leg ulcer, so VLU. Which of these wounds need compression? Again, you’re going to look at chronic venous insufficiency with lymphedema. And the two diagnoses overlap because as the tissue gets edematous, it shuts down the lymphatics and causes secondary lymphedema. And both of these occur often to patients who are obese. So obesity contributes both to chronic venous insufficiency and lymphedema so they occur in conjunction. And both of these diagnoses are accepted by several insurance companies as a reason to use pneumatic compression devices. The important caveat is if it’s mixed arterial and venous, then an ABI less than 0.5 for an absolute pressure, less than 60 is an absolute contraindication of using any compression. And these are the SVS, Society of Vascular Surgery American Venous Form guidelines which will come out in the press later this month.
    [05:04] So to review, Starling’s forces are what govern normal fluid exchange. We see a drop in hydrostatic pressure from the arterial side at 15 millimeters to the normal veins at 5 millimeters. And as fluid goes out due to hydrostatic pressure at the arterial end, a lot of that fluid is collected at the lymphatics and the oncotic pressure of blood sucks the fluid back in at the venous side. This is a well-balanced limb. Most of the fluid comes back into the venous circulation and the stuff that’s not is collected by the lymphatics. So when it goes wrong, in venous pathophysiologies, you have the central component is venous hypertension. So even because the vein valve is incompetent or there’s obstruction to venous outflow or there’s a combination of both or because the calf muscle pump that acts as a pump to return, it’s like a peripheral heart, it acts as a pump to return the venous blood from the leg, that’s defective. It could be because the patient is obese, he’s sedentary or he has a diabetic foot ulcer and doesn’t walk anymore, so the pump is not working. And all these three pathologies come together because venous hypertension with backflow of the blood into veins, the veins become varicose, and you get this hyperpigmented area with blood in the subcutaneous tissue and proinflammatory factors. So, that valvular dysfunction causes increased hydrostatic pressure at the venous end rather than lower hydrostatic pressure in the venous end. And that damages the vein walls. So they have leakage of fibrinogen, leakage of leukocytes, and downstream from that, all these inflammatory factors which get trapped in the interstitium that in turn causes increased oncotic pressure. So the increased oncotic pressure and increased hydrostatic pressure basically reverses Starling’s equation and it becomes a vicious circle. Those growth factors and inflammatory tissues, that’s what causes the ulceration. So when you look at what it does to the Starling’s equation at the arteriolar and there’s still hydrostatic pressure. But as you go down to the venous end in a standing position, the pressure may be 30 to 60 millimeters of mercury. So now you have hydrostatic pressure pushing throughout the length of the capillary bed into the venous system. And as those factors and protein-rich fluid accumulate in the interstitium, it sucks out so it reverses the oncotic pressure, so all factors point to worsening edema in the interstitium. And that accumulation of fluid underlies the ulcers. Impaired diffusion of oxygen and other nutrients essential to this pathology, inflammation is downstream, MMPs, TNF alpha, VEGF and HIF, that all causes an impaired microcirculation. And that impaired microcirculation with the venous cough and all the other things that we see in pathology, that’s what causes destruction of dermis and the ulcer. So reversing the fluid accumulation is central. Restoring Starling’s curve, that’s what we’re trying to do. And that’s the role for compression. In the supine position, our venous pressure is 20 millimeters of mercury. And lower extremity veins are narrowed successfully by 10 to 20 millimeters of extrinsic compression. But when we stand up, depending on our height, the venous pressure in the feet may be as high as 60 millimeters of mercury, and lower extremity veins need 35 to 40 millimeters of extrinsic compression to restore that extrinsic pressure and counteract the oncotic pressure going against it and the hydrostatic pressure going against it. In fact, the safe upper limit for sustained compression is 60 millimeters. Though, if you use intermittent compression, you can pump even higher than 60 millimeters. The standard for an active ulcer with venous edema is to use a four-layer bandage. The terminology has recently changed from multilayer to multicomponent because even if you use one layer and wrap it with 50% overlap, it becomes a multilayer. Well, this is the only RCT that came out recently that compares a standard widely used four-layer bandage versus what we call class 3 stockings. Those are the tight compression stockings that deliver 30 to 40 millimeters of mercury, and that’s what prescribed venous ulcers. They looked at 103 patients. They followed them up for six months. They got excellent results partly because these were supervised, the compliance was insured. 86% with the bandage versus 77% with the stocking healed and that’s non-significant.
    [10:05] However, the median time to healing was 10 weeks versus 14 weeks. Median time to healing, as I’ll show you at the end of the paper, that’s what causes the expense associated with care for VLUs across at least the United States. Its labor charge is associated with putting the bandage on. That’s what’s causing the cost. So what is this four-layer compression bandage? The first layer is just absorbent padding. Now, if you have an active ulcer, you put medication on it, you put a non-adherent layer on it. And then after that, you put this cotton padding layer. There’s no tension. It’s done in a spiral fashion with 50% overlap. You start at the toes. You cover that with a light conformable layer. This is done in a spiral manner. And there’s a mid tension with 50% overlap. Then there’s a light compression there. This is done in figure of 8s. There’s a line in the middle that helps you make those figure of 8s. It’s 50% extension again. And finally, there’s a flexible cohesive layer. It’s done in a straight spiral. It’s 50% extension, 50% overlap. As you can see, it’s more than a patient can figure out. If he has a family member who’s a nurse, he’s lucky. He cannot do it himself. So, this is the full four-layer multicomponent bandage and this works if the patient is compliant. You need to have an ABI more than 0.8 and it delivers 40 millimeters mercury at the ankle and graduates up only to 17 at the knee. So it’s not enough to counteract the effective venous hypertension throughout but it will cure patients who are compliant with it. The advantages, it gives some compression for up to a week, it absorbs the exudate for up to a week. So your visiting nurse can go once a week and change the dressing. The disadvantages, the application is complex, the patient cannot do it himself or herself. And as the leg shrinks, it actually gets too loose. So towards the end of the week, it may not be giving any compression. And finally that gradient, it doesn’t deliver consistent 15 millimeters or so compression all the way up to the knee and it smells. After a week, it just smells putrid. But that is the standard. The disadvantages, this is a paper from a very famous vascular surgeon down in Mississippi. He looked at 3000 patients with venous insufficiency and they have all been taken care of for at least six months by PCPs, podiatrist or vascular surgeons. Only 21% actually used a compression, 63% had never used it in the six months they have been seen. They’re unable to wear it without help. It cut off circulation. It hurt. It was too hot to wear. And in some cases, they said it was too ugly to wear. And so their legs were more beautiful without that. But this is the deal. You prescribe compression, you feel good about what you’re doing, and then two-thirds of these patients never even try it. So they come back to you and say, doc, what you’re doing doesn’t work. And when you get down at the nitty-gritty, you found out they actually didn’t put it on. So that’s what we’re faced with. And this is the Canadian agency for drug therapeutics and healing. It’s their governmental agency that just published their guidelines for chronic wound healing. And they said noncompliance due to pain discomfort or lack of understanding of how simple this rule is, really condemns this unless you could have followed up. So we come to intermittent pneumatic compression. Now, these are the first guidelines that, again, are coming out later this month. It is available online from the SCS that say that intermittent pneumatic compression is the modality that can be used when either compression options are not available. That means you don’t have a nurse to go put them on. When they cannot be used, patient refuses or have failed to aid in venous leg ulcer healing after prolonged compression therapy, which they defined as two months. And they give it a level 2C which means it’s lots of observational trials, there are no RCTs. But the body that wrote these guidelines, the body of vascular surgeons wrote these guidelines, really feels that it has value to add to the patient. So how does it work? It acts by contact with the skin. It delivers more than the 30 millimeters of pressure required. In fact, it delivers it in a graduated fashion from the foot at 50 and then it pumps up. So the fluid takes the path of least resistance. The gradient pressure creates movement. And there’s never reversal of flow by giving, say, 50 millimeters causing a bind by compression garments at the knee. And so both the venous and lymphatic tissues that these pressures transmitted to in the dermis, both of them are impacted. And it has most intermittent devices by definition. They have a time when the pressure is off. So we don’t have consistent pressures that would damage the veins and lymphatics.

    [15:05] So they have two different devices. Some of them use a gradient, some of them don’t. The gradient, the advantage or the proposed advantage of this gradient is that it’s a sequential pressure from distal to proximal delivering higher pressures at the foot and then low pressures up. And this is physiological consistent of what we understand of venous ambulatory pressure. When you stand up, the highest pressure is the column of water in the foot. So there’s this moving way of compression. They are much more comfortable because the resting pressure, that means when you put the bandage on with the guys lying down, all you need is 25 millimeters of mercury. But when you put that four-layer bandage on, it delivers all these pressure right upfront. So that’s 40 millimeters of mercury consistently. And as soon as they stand up, they feel a bursting pressure and they will not use it, and that’s why they say it’s too painful. So you can deliver higher pressures and have it by delivering it intermittently, you don’t have that consistent pain. Versus static compression which causes a lot of discomfort. And because there’s discomfort, there’s less compliance and that’s why we see that there are unsatisfactory outcomes. The final thing that, for me, is important with patient who are, oftentimes, extremely obese is that it’s easy to put on. This is a one-piece garment, it’s sized to the patient, the delay and delivering is a couple of weeks, and there are these big straps on the top of it. Even if you’re so obese, you haven’t seen your toes in years, you can get the straps put your foot in and put it all the way up to your groin. They have different pieces. This is just a simple example. This is available through many manufacturers. But the keys to me is the after care. Compliance with these patients is key. And I’m going to go into why you should choose your company carefully. It takes an hour and a half or so a limb. If you have two legs, you can actually put it on both legs and the cost of ordering a second garment is minimal versus the waste of time. If I have an in-patient, I just order one because even if it’s 150 bucks, that’s a 150 buck saved, and they’re just using it on one side and the other. But if you’re using it for an hour and a half, I call it TV time. They just put it up with the TV. He’s showing reading a magazine. He’s the last person on Earth who does that one. So the advantage of intermittent pneumatic compression over traditional compression, the patient gets trained. If you choose the company right, the patient will get trained on how to use it at home. Some of these devices have in-built computers which will actually tell you how long the device has been on. And these guys will give you feedback, telling you that look, you’re spending X dollars and he’s not using it, sitting in the cover, I want to take it off then. And it’s not painful, it’s not inconvenient to put on. Once they get the hang of how to put it on and once they see the results, they’ll start being more adherent to it. And always tell them TV time. The only guy who didn’t like that was, when he puts it up, he says it gets in the way of my eyes to my TV, so I had to get him to put the TV higher. You have to help your patient out. We’ve had excellent results. These are difficult to heal venous leg ulcers in patients who are mostly morbidly obese and we’ve thrown everything the system has at them. And I’ve come upon this frustration. What do you do with this then? When you can’t get these ulcers to heal and you just look at the guy and you feel it’s impossible for me to help you out. So we have 27 patients that we referred over 12 months this month. Actually, I haven’t used it for that long. Six patients who discontinued, two due to medical reasons, they went into CHF, the other guy, there were other complications that he had to get admitted for, four were non-complying. Two have been unreachable for two months to the standard follow-up. And so if we assume them noncompliant, our noncompliant rates are now 22% compared 66% of traditional compression. Two of them are in-house admitted for other diseases, so we’re having them place in-house. Those who are complaint the patients have excellent results, you see them back here, it’s literally amazing, the change in the girth. The patient was satisfied because they finally see change in what they thought was a life condition they’d never get to leave. And the five of us who use it and all of us report consistent results. But this seem grade three evidences, it’s not a randomized control of trial. The disadvantages, again, there’s no randomized control data, the database looked at it and said we have no recommendations. All companies and all manufactures don’t have the computer, they don’t know of a feedback. You’re getting what you paid for to some extent and then there’s a little bit of difference in how they deliver the device, which since there’s no data, I haven’t gone into. It is expensive but it’s an expense compared to what? In the US, we spend 2.5 billion dollars on treating venous leg ulcers.

    [0:20:03] The key determinant of cost is the duration to heal and the occurrence. In 1998, we estimated the monthly costs were $2500 and 50% of those cost were driven by labor cost by home healthcare. So the key is prevent home healthcare, get them to heal quickly and prevent reoccurrence. And I think intermittent pneumatic compression sort of does all three of those. More recently, this is out of Tufts this year, 84% patient seen in wound clinic, their minimum follow-up was six months, the median was one year. These are actual costs to patient, not charges to patient, 15,732 that’s a lot. During the median follow-up with one year alone and during that time 60% healed, the average cost is 10,500, 20% did not heal, threefold increase in cost, 20% reoccurred within the year and the cost went up 12,700. And the mean visiting nurses over that year per patient, the cost were $11,000. So any device that takes us away from having home visits by nurses increases labor, especially in the current healthcare environment, let me put it that way. Anything that we can do to prevent that is going to give better patient results, patient satisfaction and improve our economy with $2.5 billion being thrown down the drain. So if you see it in context to the costs, I think it’s reasonable to consider a more effective therapy. In conclusion, large lower extremity wounds complicated by edema need compression. Multicomponent dressings are the mainstay of traditional therapy. Intermittent pneumatic compression may have an adjunctive role provided there’s good follow-up to ensure compliance and we still need that RCT data. Thank you very much.