Negative Pressure Therapy Demonstration
- Janet S. Mackenzie, MD, ABPS, CWSP, AAGP
- December 20, 2012
Part 1 - Indications, Contraindications & Dressing Selection
Understand Wound Care:
Negative Pressure Therapy Demonstration- Part 1
Indications, Contraindications & Dressing Selection
Commentary: Japa Volchok, DO
In this demonstration we will be discussing the indications and contraindications for negative pressure therapy. Negative pressure therapy is also commonly referred to as V.A.C. or V.A.C. therapy. This is a trademark name from K.C.I. For the purposes of this demonstration, negative pressure therapy will be used to indicate any type of negative pressure therapy system where a dressing is applied to a wound and then is connected to a device that generates continuous or intermittent suction and has been approved by the F.D.A. for prescription by physicians or other medical staff for specific indications.
Negative pressure therapy is a treatment option for patients that have wounds that are healing by secondary or tertiary intent. These are wounds that would normally heal slowly and fill in with granulation tissue from the base of the wound and the edges of the wound before the wound would re-epithelialize.
Negative pressure therapy increases the speed at which the wound heals. In addition, negative pressure therapy promotes wound healing by removing edema, removing exudate as well as other factors within the wound.
Negative pressure therapy is indicated for a variety of conditions including pressure ulcers, venous ulcers, post-surgical wounds and other conditions.
There are several contraindications to negative pressure therapy. These include malignancy within the wound, untreated osteomyelitis, a fistula that it non-enteric or has not been explored, necrotic tissue with eschar. As well as other relative contraindications that include sensitivity to the dressing material. The adhesive commonly contains acrylic. Some patients may have an allergy to acrylic. In addition, there are negative pressure therapy dressings that contain silver. If a patient has a silver allergy or a silver sensitivity it may be contraindicated.
There is one area of relative contraindication that involves patients that are at higher risk for bleeding. These include patients that may be on Coumadin or Plavix. In addition, negative pressure therapy is contraindicated when there is exposed blood vessel, nerve or an anastomotic site, either a vascular anastomosis or an enteric anastomosis.
The wound models and dressings that will be demonstrated in this video today are courtesy of K.C.I. These are proprietary products and there a variety of vendors that supply dressings and vacuum devices.
Negative pressure wound dressings come in a variety of designs. The model that we will be using for this demonstration today is a foam-based primary dressing, this is supplied by K.C.I.
This foam dressing as seen here is this black foam. This comes in a variety of sizes and shapes. In addition, this can be cut or molded to the specific sizes and dimensions of the wound.
Also supplied in this sterile packaging is the adhesive dressing that is placed over the primary foam dressing, as well as the tubing that leads to the negative pressure generating unit.
The foam dressings come in a variety of sizes from a medium size, small size as well as larger sizes. In addition, there are pre-cut foam dressings supplied in a variety of shapes and sizes. Foam is also supplied in a variety of thicknesses. These foam dressings can be cut as well as stacked to fill the wound bed.
There are, in addition, gauze-based negative pressure therapy systems and other foam-based negative pressure therapy systems. Some alternatives include shapes that are moldable based on a spiral as well as specific dressings that have been impregnated with silver.
This is a silver impregnated sponge that is supplied by K.C.I. This is one that can be an adjunct for use in a wound that may have an infection that is being treated simultaneously with systemic antibiotics.
One significant note to be made is that the adhesive dressing that is supplied with the primary foam dressing, in the K.C.I. system includes clearly marked “number 1” and “number 2.” These are the order with which this is removed for application to the patient. This will be demonstrated subsequently.
Part 2 - Wound Prep & Dressing Application
In Part 2 of the Negative Pressure Therapy Demonstration, Japa Volchok, DO discusses proper wound prep and dressing application. This is a step-by-step instruction of preparing a wound for negative pressure therapy, or “Wound V.A.C. therapy. This demonstration is performed by a trained wound care physician for educational purposes only and should not be tried at home.
Understand Wound Care:
Negative Pressure Therapy Demonstration- Part 2
Wound Prep & Dressing Application
Commentary: Japa Volchok, DO
If negative pressure therapy has been ordered for your patient and is now time to apply the dressing, it is useful to have additional items available. These would include several packets of skin prep, as well as a suture removal kit. It is important to maintain the sterility of the dressing packages up to the time of application.
At the time of dressing application, it is important to follow standard precautions. It is not a sterile procedure, so there’s not a need for sterile gloves. It is not necessary to perform a surgical prep of the wound. There are instances in the acute setting when a negative therapy dressing may be applied in a sterile environment. However, for the purposes of this demonstration we are performing a clean procedure.
Once you have selected the appropriate size of the sponge based on the wound defect to be filled, you can then open the packaging and proceed with the application of the dressing.
This demonstration is an artificial wound model that has been supplied to us by K.C.I. You’re seeing here that the patient has an ischial ulcer that is a stage 4 ulcer. There are muscle fibers present in the base of the wound. This wound has no evidence of necrotic tissue and is beginning to granulate. This would be an indication for negative pressure therapy. And, negative pressure therapy would be used to promote wound healing by reducing edema in the surrounding wound bed as well as removing exudates and other fluids that may be present in the wound.
There’s no evidence of necrotic eschar or active infection. So, this makes it a fairly straight forward application of a negative pressure dressing. Once we have identified our wound, measured it, staged it and verified that the orders are correct for negative pressure therapy.
We would go ahead and select an appropriate sponge. This sponge, as you can see, is much larger than the wound. It is now useful to have sterile scissors or a sterile scalpel. We can now begin to cut the foam dressing to a size that is slightly smaller than the wound. It is important to cut the dressing over a clean surface and not over the wound so that particles of the foam dressing do not fall into the wound.
Once the foam has been cut and shaped to a dimension that approximates that of the wound, we would gently insert it into the wound. When shaping the foam dressing for application into the wound, care should be taken that the foam approximates the size of the wound defect. And, when negative pressure is applied, it should just fill the wound or slightly under-fill the wound. You do not want to have a dressing that fills the wound such that when negative pressure is applied there is now sponge dressing on top of healthy skin. There are two methods to prevent the sponge from overlapping healthy tissue. One is to correctly size the sponge initially so that when negative pressure is applied, it does not overlap normal skin.
Another method is to use your adhesive dressing to create a barrier around the wound to exclude the healthy skin from the foam dressing. This would be achieved by cutting a portion of your adhesive dressing, removing “number 1,” occluding the wound, removing layer “number 2,” and tearing off the leading edge.
We would now then cut out the dressing around the area keeping the normal skin covered with the adhesive dressing. We would then insert the sponge. Now you can see that even though the sponge is above and covers the edge of the wound, on to normal skin, the initial layer of adhesive dressing provides a barrier.
Once we have sized the foam dressing appropriately, we are now ready to apply the dressing and the adhesive barrier that will achieve a vacuum seal for negative pressure therapy.
Initially, we would like to take skin prep and prep around the wound so that the adhesive will more readily adhere. Once this has occurred and we have inserted the foam dressing into the wound, we would select an appropriate sized piece of the adhesive covering. Using our scissors this could then be cut to an appropriate size.
When working with the adhesive, it is generally easier to use if we cut in a direction that allows all edges of the adhesive backing removal to be readily accessible. A dressing that has been completely cut free from the leading edge is now very difficult to peel the layers apart.
This dressing has an initial layer that is removed from the adhesive and discarded. After removing the initial, lay that down on the skin and rotate that up. Now, we would start to slowly pull the dressing backing off as we stick the adhesive down surrounding the wound.
Once this has occurred and we have achieved circumferential adherence of the adhesive. The secondary layer, which is a layer of thickness that is added to for ease of working, is removed. This is what is labled as “number 2.” Once that has occurred, we can remove the blue leading edge. This is included for ease of work.
Now we have the wound filled with an appropriate sized negative pressure therapy sponge dressing. It has not occluded, or covered, healthy normal skin. We have now completed the initial application of the negative pressure therapy sponge dressing and the adhesive secondary dressing. At this point we are ready to connect the sponge dressing to the negative pressure source. This is achieved using the supplied tubing and the adhesion system.
In application of the tubing that is connected to the negative pressure generator, this tubing is supplied with an adhesive and a working backing that is then secondarily removed. At this point, our sponge is completely occluded by the film adhesive dressing. The first task is to remove a portion of the adhesive dressing over the sponge. This can be accomplished in a variety of manners. The simplest is to use a pair of scissors and cut out a portion of the adhesive. It is not a problem if you also remove part of the adherent sponge. It actually makes this an easier process. It is important to have an adequate size opening to the sponge, through the adhesive so that the negative pressure tubing is not occluded when it is attached.
Remove the backing and place the negative pressure device centered over the hole that you made in the adhesive dressing. You can now remove the secondary portion and the overlying working backing. This splits apart. We now see that we have applied the negative suction tubing over the negative pressure sponge dressing and the adhesive barrier.
We have cut an appropriate size hole in the adhesive barrier and the negative pressure tubing is now placed over that and is well adhered. At this point, the wound has been appropriately dressed with the negative pressure therapy sponge dressing and its components. We are now ready to connect the tubing to the negative pressure therapy generator.
Part 3 - Device Operation
In Part 3 of the Negative Pressure Therapy Demonstration, Japa Volchok, DO demonstrates operation of the “Wound V.A.C.” device. This is a step-by-step instruction of preparing a wound for negative pressure therapy. This demonstration is performed by a trained wound care physician for educational purposes only and should not be tried at home.
Understand Wound Care:
Negative Pressure Therapy Demonstration- Part 3
Device Operation
Commentary: Japa Volchok, DO
There are a variety of negative pressure therapy systems. This is a K.C.I system known as a V.A.C. The V.A.C. is supplied in a portable model that is battery operated as well as A.C. current operated. In addition, there are other larger units that are based on direct, non-battery operated power use for different indications.
This device has two components to it. One is the permanent device itself. That has the generating device that creates the suction or negative pressure. There is then a disposable component which is the canister that will collect the drainage from the wound. It includes the edema fluid as well as the exudate and other fluids that are removed from the wound. This canister is supplied with a chemical absorbent. That absorbs the fluid as well as graduated marking that measures the volume of the fluid that is removed from the wound.
One would take the generator device and attach the suction canister to it until there is an audible click and the canister is adhered to the machine. At this point, the machine is now ready to be connected to the tubing that has been previously attached to the patient’s wound.
The tubing that we have attached to the patient model, or in your case, your patient’s wound, is supplied with a closure device as well as a locking connection. Similarly, the canister that attaches to the generator has a matching paired locking device as well as an interlocking connection.
To lock the device portion of the tubing to the patient portion of the tubing, one would push the female and male end together and turn part of a turn to lock. Similarly, you would turn and pull this apart to disconnect the patient from the generator.
It is important that when disconnecting the generating device from the patient, one would close off the patient side before disconnecting. This prevents outside air from being sucked back into the wound through the tubing. Once continuous negative pressure has been created by the generator, you will see the suction tubing adhere more closely to the wound.
The generators are designed so that there are a variety of audible alarms. Most commonly, an alarm will generate if the collection canister is full or if in application of the dressing, the seal that allows the continuous negative pressure suction to be generated directed at the wound bed, is broken.
If the seal is broken, you may hear an audible alarm from your generating device. If this occurs, one would need to examine the dressing application. There are a variety of ways to seal an area where there may be a leak. One common way is to apply skin prep over the dressing. This may seal a minor leak. Another method that may be required is application of an additional piece of adhesive over the area where there is leakage.
One way to determine if there is leaking, or failure to achieve complete sealant with the adhesive, is to examine around the wound circumferentially and palpate. If you suddenly achieve suction at one particular point, you can identify that as your leak.
In a subsequent video, we will demonstrate tips and tricks to deal with difficult wounds, where leaking or failing to achieve suction may be more likely.
There are several specific indications and contraindications to negative pressure therapy. One should carefully review the manufacturer’s educational materials and the indications for use of a specific dressing and negative pressure therapy system.
Part 4 - Tips and Techniques
In Part 4 of the Negative Pressure Therapy Demonstration, Japa Volchok, DO discusses various tips and techniques. This is a step-by-step instruction of preparing a wound for negative pressure therapy. This demonstration is performed by a trained wound care physician for educational purposes only and should not be tried at home.
Understand Wound Care:
Negative Pressure Therapy Demonstration- Part 4
Tips and Techniques
Commentary: Japa Volchok, DO
This video demonstration includes several tips and pointers that will allow you to correctly apply negative pressure therapy and achieve a successful dressing application. One common problem that may occur when applying a negative pressure dressing is it may be difficult to achieve a seal around a specific wound. Commonly, pressure ulcers develop in locations of the body where the skin’s surface area is varied in its texture and depth.
This is a sacral wound where you can see that within the cleft of the buttock here, there is a relative deficit. When applying the adhesive, it were laid flat, you would see that there’s a large defect here. To get the adhesive to stick and seal can sometimes be difficult.
One assist in achieving a good seal over the wound is to use an ostomy or stoma paste. Stoma paste is supplied by prescription or from your medical device vendor. It commonly comes in a tube. Sometimes it is in a strip or roll. What you can do with stoma paste, is apply it in the area where there is a defect in the skin, prior to applying your adhesive.
Once you’ve applied your stoma paste, you can then apply the adhesive directly over that as you will see in this demonstration. Your adhesive can stick directly to the stoma paste that has filled the deficit. You can gently mold the stoma paste with your fingers. This will greatly aid you in achieving a seal around the wound and over the negative pressure dressing or the sponge in this case.
It is not uncommon when applying your suction tubing that the tubing may run across a portion of the body where you would not want the patient to be laying on tubing. This suction device can be located elsewhere, off a site of support. To do that, we would construct a bridge.
There are several options for constructing a bridge. Some negative pressure devices, actually have pre-constructed bridging tubing. One example of that is demonstrated here.
If you prefer to construct a bridge without using a pre-made device, that is relatively easily done. The first step is to place your sponge dressing or other dressing into the wound. Take away a portion of the adhesive. Now select a site away from pressure where you would like the tubing to sit. In this case, we’re going to bring it off to the side as illustrated here.
What you would want to do first is to lay down a layer of adhesive dressing, from the wound extending to where you would like the negative pressure tubing to be located. In this case, off to the side. Once this has been lain down and the working layer has been removed, the next step is to cut a strip of your foam dressing, approximately the length of the distance between you wound and where you would like your pressure tubing to be located.
Once you have cut a piece of foam that extends from your wound to where you would like you negative pressure tubing to be located, you would then position that. Then, cover with another layer of adhesive. Once you have entirely sealed this second layer of your foam dressing, you’re now ready to peel this off.
You have now constructed a bridge that extends from over your primary dressing, where you’ve cut a hole in the sealant that covers the sponge that’s filling the wound. This is now on top of adhesive. It is not in contact with normal skin. It extends out to where you would like to position your tubing that will connect to the negative pressure generator.
Similarly, as we have done over the wound dressing, we cut a portion of the adhesive away. As I had said before, if you remove a portion of the sponge with this it’s not a problem. So, feel free to carve as you need with your scissors. Discard that.
You will now then take your tubing that connects to the negative pressure device, remove the adhesive, and this will go over the area where you have cut away the adhesive. Completely adhere that over and remove the backing.
Now you are ready to connect this tubing to the negative pressure generating device. You will see that once the negative pressure is active and is being generated by the device, this bridge will suction down. Any fluid or exudate will pull through the sponge that’s in the wound bed, come up through the hole that we had cut and come out through the bridge and through the tubing. The underside of this particular portion of foam dressing is in contact with adhesive and is not in contact with healthy skin.
This construction of a bridge allows you to locate your pressure tubing away from the wound site if the wound is relatively small. Or, locate the pressure tubing off an area where you don’t want it to be a point of contact. This would be over and area such as the back, where it would be uncomfortable for the patient to continuously lay on the tubing itself.
As you can see here, our dressing has negative pressure attached to it. The bridge has collapsed and been suctioned down as well as the dressing or the sponge which is in the wound itself. This is the appearance you would see with a well-sealed, well-constructed primary dressing with a bridge created off to the side. You will note that when the negative pressure has been applied to the wound that this particular wound now has a concave or indented appearance to it.
If you have wounds that have significant depth and they are deeper than the thickness of your sponge, you can create two layers of dressing where you stack a sponge on top of the other sponge. One indication that this might be something that you would consider is if you’ve connected your dressing to the negative pressure source and you have a very concave appearance to it, it would be a reason to consider two layers of sponge.
As in the previous demonstration, it is important to protect normal skin from coverage by the sponge dressing. And, it is important to achieve a seal around the entire wound. You can see that the stoma paste has allowed us to produce an excellent seal on this inferior aspect of the wound. Often times due to a patient’s movement or anatomy you cannot achieve an adequate seal.
There are several specific indications and contraindications to negative pressure therapy. One should carefully review the manufacturer’s educational materials and the indications for use of a specific dressing and negative pressure therapy system.
There are several points that should be taken into consideration. If a negative pressure dressing is malfunctioning and there’s an inability to achieve a seal, and the therapy is not active, there is a time constraint that should be considered before switching to another type of dressing. In addition, if blood is noted within the wound bed and there is blood collecting in the collection container, this would be a concern and should be brought to the medical practitioner’s attention.
The use of negative pressure therapy is a by prescription treatment modality and the ordering healthcare provider’s instructions should be followed. In addition, specific manufacturer’s instructions regarding individual types of dressings and specific negative pressure devices should be taken into consideration. This video is for educational purposes only.
The wound model in this demonstration as well as the negative pressure generator and the supplies, have all been donated by K.C.I. for educational purposes.
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