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Guidelines for Using
Negative Pressure Wound Therapy
Advances in Skin & Wound Care: The Journal for Prevention and Healing
November/December 2001 
Volume 14 Number 6

BY SUSAN MENDEZ-EASTMAN, RN, CWCN, CPSN

The author has disclosed that she has no significant relationships with or financial interests in any commercial companies that pertain to this educational activity.

PURPOSE

To present information on the rationale for and use of negative pressure wound therapy.

TARGET AUDIENCE

This CME/CE activity is intended for physicians and nurses with an interest in using negative pressure therapy in the treatment of wounds.

LEARNING OBJECTIVES

1. Describe the rationale for using negative pressure in the treatment of wounds.

2. Discuss guidelines for the appropriate use of negative pressure wound therapy.

3. Identify patients with wounds who would benefit from negative pressure wound therapy and patients for whom this modality would be contraindicated.

Submitted April 30, 2001; accepted in revised form September 26, 2001.

ADV SKIN WOUND CARE 2001;14:314-25.

Numerous studies have been conducted to determine the effects of negative pressure on wound healing.1-3 These studies have shown that controlled negative pressure assists in wound healing by:

  • providing a moist, protected environment

  • reducing peripheral edema around the wound

  • stimulating circulation to the wound bed

  • decreasing bacterial colonization

  • increasing the rate of granulation tissue formation and epithelialization.

    Negative pressure wound therapy (NPWT) was developed in the 1990s by researchers at Wake Forest University School of Medicine, Winston-Salem, NC. The concept was based on the mechanics of physics. The application of controlled subatmospheric pressure causes mechanical stress to tissues. Mitosis is stimulated, new vessels are formed, and the wound is drawn closed.4 The degree of pressure to the wounded tissue is small, but when all areas of the wound work together in an effort to close toward the center point, the effect of negative pressure becomes impressive and results in quicker healing and resolution.

    The Science Behind NPWT

    Moist wound healing

    NPWT applies subatmospheric pressure, or suction, to the wound bed via a computerized therapy unit attached to an open-cell foam sponge that is placed in the wound and secured with an adhesive drape (Figures 1 and 2). The adhesive drape helps to provide a semiocclusive environment that supports moist wound healing, which has been the standard for wound care since the mid-1980s.5 The drape is vapor permeable to facilitate gas exchange, an important consideration when treating wounds infected with anaerobic organisms that would thrive in an occlusive, oxygen-depleted environment. The foam and drape also protect the wound base from environmental contaminants and reduce the risk of friction or shear, enhancing the body's ability to heal.

  •  
    Figure 1. NPWT DRESSING

    After cleansing the wound and preparing the periwound area, cut the NPWT foam to fit the shape and size of the wound, including tunnels and undermined areas. Place tubing on top of or inside the foam. Cover with clear drape; pinch dressing under tubing. Connect tubing to canister and ensure that the seal and target pressure are appropriate. Ensure that sponge has collapsed and fills the entire wound bed.
    *Consult treating physician for individual patient conditions and treatment protocols. Consult device user manual and recommended guidelines for details before use.

    Figure 2. PLACEMENT OF NONADHESIVE DRESSING OVER EXPOSED BONE TO RECEIVE NEGATIVE PRESSURE WOUND THERAPY

    2A. Wound with area of exposed tibia.

    2B. Nonadherent dressing placed over exposed bone before application of the polyurethane sponge. This dressing was also placed around the wound because the patient had fragile skin.

    2C. A small piece of sponge is laid over the nonadherent dressing.

    2D. The polyurethane sponge is cut to fit the size of the wound.

    2E. Subatmospheric pressure is applied.

    2F. Note granulation tissue over the tibia 72 hours post-NPWT.

    *Consult treating physician for individual patient conditions and treatment protocols. Consult device user manual and recommended guidelines for details before use.

    Peripheral edema and circulation

    The tissue surrounding a wound is typically characterized by a localized buildup of interstitial (third-space) fluid.6 This fluid mechanically compromises the circulatory and lymphatic systems, impeding oxygen and nutrient delivery to the tissue and supporting inhibitory factors and bacterial growth. Stagnant wound fluid has been shown to contain elements that delay wound healing by suppressing proliferation.7

    With NPWT, wound fluids are evacuated via a tubing system placed in or on the foam at one end and connected to a disposable canister housed in the therapy unit on the opposite end. Removing this stagnant fluid allows circulation and disposal of cellular waste via the lymphatic system. Laser Doppler flow studies have shown a significant increase in blood flow adjacent to a wound receiving negative pressure as a result of decreased peripheral edema.8

    Bacterial colonization

    When microorganisms invade tissue, infection is present (defined as greater than 105 organisms per gram of tissue).9 These microorganisms consume the nutrients and oxygen that would otherwise be directed toward tissue repair. They also release enzymes that break down protein, which is an important component in wound repair. Reducing the bacterial load of a wound improves its healing capacity because the body can then concentrate on healing rather than on fighting invasion from bacteria, viruses, or yeast. NPWT can accomplish this by reducing the amount of stagnant infected fluid in the wound.8 As mentioned earlier, circulation is enhanced when interstitial fluid is removed. Any increase in circulation and oxygenation to compromised tissue improves the area's resistance to infection, allowing healing to progress.6,8,10

    Granulation tissue

    Granulation tissue is a mix of small blood vessels and connective tissue in the base of a wound. This base forms a nutrient-rich matrix that can support the migration of epidermal cells across the wound bed. A well-granulated wound provides an optimal bed for epidermal migration and for skin grafts as the newly formed capillaries incorporate the transplanted skin. Studies have shown that granulation tissue formation is enhanced by negative pressure by virtue of interstitial fluid resolution and the resulting increase in circulation.8

    The science behind NPWT is significant because it enhances in vivo reparative mechanisms to promote wound healing. NPWT does not replace surgical procedures, but may allow the wound to progress to the point that a less-invasive procedure is possible.

    NPWT has demonstrated positive outcomes in a variety of wounds, but guidelines and safety measuresdeveloped using evidence-based researchmust be diligently maintained to protect the patient. Any therapy has the potential for harm when not used appropriately.

    Patient Selection

    Indications and contraindications

    Before NPWT is applied, the patient and wound must be assessed for appropriateness. The Food and Drug Administration (FDA) approved NPWT in March 1995 for the treatment of nonhealing wounds. Its indications were expanded in January 2000 to include chronic, acute, traumatic, and subacute wounds; flaps; and grafts.

    The manufacturer of the only NPWT system currently available in the United States (Vacuum-Assisted Closure, [V.A.C.]; Kinetic Concepts, Inc [KCI], San Antonio, TX) considers the following to be contraindications for the therapy: wounds with necrotic tissue, untreated osteomyelitis, fistulas to organs or body cavities, placement directly over exposed veins and arteries, or malignancy within the wound.

  • Devitalized tissue. Wounds must be cleared of all devitalized tissue before NPWT placement. This includes the debridement of bone if osteomyelitis is present. Osteomyelitis must also be treated with appropriate antibiotics that address the underlying infection.

    Anecdotal reports have detailed the use of topical enzymatic debriding agents in conjunction with NPWT to increase the rate of healing. Although no scientific studies are available to support these claims, clinicians report that thin layers of slough or fibrin buildup on the wound bed can be covered with a selective enzymatic debriding agent prior to sponge application. This is based on the theory that chemical agents will break down devitalized tissue on the wound bed without interfering with NPWT. However, not all topical enzymatic debriding agents are selective and care must be exercsied in choosing one for this purpose. Some have the potential to damage live tissue.

  • Fistulas. Although the manufacturer lists wounds with fistulas to organs or body cavities as contraindications for NPWT, many clinicians have used NPWT off-label to manage or close these fistulas. For example, clinicians have reported using NPWT on a short-term basis to contain drainage and allow the skin to heal when a draining fistula has compromised adjacent skin.

    Chronic and newly created fistulas have also been successfully closed with NPWT. The relatively small volume of the NPWT canister (300 mL, which can contain 280 mL of fluid) may seem to make NPWT an expensive treatment option for a high-output fistula. If closure occurs, however, the need for another collection system is eliminated.

    There are inherent risks associated with this type of application. The manufacturer of the currently available NPWT system specifically states that wounds with fistulas to organs or body cavities are contraindications for this treatment. If this warning is considered and NPWT is still thought to be prudent, the liability falls with the prescriber.

  • Organs and exposed blood vessels. A nontoxic, nonadherent barrier should be used to protect organs and exposed blood vessels from the porous texture of the polyurethane sponge used in NPWT; placing the sponge directly on these structures is contraindicated. Subatmospheric pressure may be harmful to tissue in body cavities, therefore, NPWT should be applied only after careful consideration of the situation and possible benefits and risks associated with the use of subatmospheric pressure.

  • Malignancy. NPWT is inappropriate in a wound associated with malignancy. When mechanical stretch is applied to normal cells, it results in increased proliferation. However, biologically, cancerous cells often are not anchored and do not respond to the same stimuli as healthy cells, thereby rendering NPWT ineffective.

    Clinical considerations

    A patient with a wound must have the basic capacity to heal in order to benefit from subatmospheric pressure. That may not be the case if the patient's nutritional status is inadequate, if he or she has an untreated infection, or if death is imminent. In these situations, NPWT should not be initiated.

    Without adequate nutrition, a patient will be unable to heal a wound, regardless of whether subatmospheric pressure therapy is started. If oral intake is poor, a supplement should be considered to assist with wound healing. Protein is an important factor when trying to rebuild within the body. Albumin or prealbumin levels can be monitored to track the nutritional status of a patient with a nonhealing wound.

    NPWT can be used as an adjunct therapy in infected wounds, but not as a sole treatment. Appropriate antibiotic coverage and surveillance of infection must be maintained throughout the wound healing process. Subatmospheric pressure therapy has been shown to be effective in supporting the body's defense system against invading organisms; however, it has not been proved to be an adequate treatment for infection by itself.

    If a patient is near death, NPWT should not be used. The patient's overall health outlook should be considered before initiating any treatment. If it is unlikely that a patient will live more than 6 months, NPWT is inappropriate.

    The incidence of pain related to NPWT is usually low. However, NPWT should be discontinued if a patient complains of pain at the wound site during the treatment and comfort measures, such as analgesics, a change to continuous from intermittent subatmospheric pressure, or reduction of subatmospheric pressure, are ineffective.

    Guidelines for Use

    Once NPWT is determined to be appropriate for the wound, the following guidelines (suggested by the manufacturer) should be used for application, treatment, and assessment. This treatment protocol is designed to incorporate evidence-based research for best practice. As with any device application, the clinician should consult the operation manual for NPWT and any published recommended guidelines for details on proper application. The clinician should also take into account the patient's condition and institution-specific treatment protocols.

    1. Gently remove the NPWT dressing (if applicable) and discard per institutional protocol.

    When removing the adhesive dressing, care must be taken to gently lift, rather than pull, the drape off the skin. A pulling motion can cause epidermal stripping and irritate periwound skin. A topical adhesive remover can be used to help remove the drape.

    The clinician may use normal saline solution to loosen the sponge for removal from the wound bed. Aggressive granulation tissue growth may result in tissue growing into the sponge. This could cause pain on removal. Moisturizing the sponge before removing it may lessen the discomfort and also decrease potential trauma to fragile capillaries in the wound bed.

    Institutional protocols should include universal precautions for disposal of infected waste.

    2. Aggressively cleanse the wound and periwound area.

    Guidelines on pressure ulcer treatment from the Agency for Health Care Policy and Research (AHCPR; now the Agency for Healthcare Research and Quality) recommend wound cleansing with normal saline solution under pressure of 4 to 15 pounds per square inch.11 Cleansing the wound at each dressing change is important for removing loose debris.

    3. Debride necrotic tissue if applicable.

    Chronic wounds benefit from aggressive debridement to remove debris that may be present in the wound bed, sinus tracts, or tunnels. As mentioned earlier, anecdotal reports claim that NPWT can be used in conjunction with selective topical debriding agents. No scientific studies to date support this claim.

    Osteomyelitis should be ruled out or treated according to established practice if bone is exposed. Necrotic bone must be removed to reduce incidence of future occurrence. However, do not use bonewax on debrided bone. This wax can easily break loose and migrate to other areas or clog the NPWT system.

    4. Achieve hemostasis.

    The patient should be hemodynamically stable before NPWT is initiated. Active bleeding in the wound should be controlled prior to treatment. If the patient is on anticoagulant therapy, the partial thromboplastin time and the prothrombin time should be regularly monitored to ensure that clotting times are therapeutic.

    5. Shave hair on the border of the wound, if necessary.

    A seal may be difficult to achieve if hair is surrounding the wound. Hair could also make removal of the drape painful.

    6. Dry and prepare the periwound skin, as appropriate.

    If the skin is moist due to perspiration, oil, or body fluids, a degreasing medical cleansing agent should be used. A skin protectant should always be used to protect the skin around the wound from the adhesive drape. Skin preparation agents may need to be applied around the wound site if there is difficulty achieving an airtight seal.

    7. Select the appropriate foam dressing based on wound characteristics.

    Black polyurethane foam has larger pores and is considered to be more effective for stimulating granulation tissue and wound contraction. White, polyvinylalcohol (PVA) soft foam is denser with smaller pores and is generally recommended when growth of granulation tissue needs to be somewhat restricted or when the patient cannot tolerate the polyurethane foam due to pain. Because of its higher density, the PVA foam requires higher negative pressures than polyurethane foam to work effectively. Both foam dressing kits are packaged sterile. Table 1 lists recommended guidelines for use of each type of foam during NPWT. The clinical situation determines whether the therapy is applied with sterile or aseptic technique.

  • Table 1. FOAM CHOICE RECOMMENDED GUIDELINES*

    Wound Description Poly-
    urethane (black foam)
    Polyvinyl-
    alcohol (soft foam)
    Both Either
    Deep, acute wounds with moderate granulation tissue growth X   X  
    Deep wounds with extremely rapid growth in granulation tissue        
    Deep pressure ulcers X      
    Superficial wounds       X
    Postgraft therapy   X    
    Fresh grafts X      
    Compromised flaps X      
    Tunneling/sinus tracts/undermining       X
    Diabetic ulcers   X    
    Dry wounds X   X  
    Deep trauma wounds       X
    Superficial trauma wounds        
    *Consult treating physician for individual patient conditions and treatment protocols. Consult device user manual and recommended guidelines for details before use.

    A combination of polyurethane and PVA foam can be used in the wound, depending on the desired result. Vascular ulcers do not require significant amounts of granulation tissue formation; polyurethane foam can be used in vascular ulcers to reduce edema and bacterial load. PVA foam would generally be indicated for pressure and diabetic ulcers because stimulating granulation tissue formation is a primary wound care goal. A deep wound that is in need of granulation tissue formation but has exposed tendons can benefit from a combination of PVA foam placed on the fragile tendon and polyurethane foam used to fill the large remaining defect.

    8. Select an NPWT sponge kit that is the appropriate size to fill the entire wound cavity.

    The dressing kit should be opened on a clean, dry surface. The NPWT foam is then cut to fit the size and shape of the wound, including tunnels and undermined areas. More than 1 piece of foam can be used if necessary; however, each piece of foam must come in contact with another piece of foam to achieve uniform compression when subatmospheric pressure is applied. It is important to document how many pieces of sponge are placed in the wound at each dressing change so that they can be accounted for when removed.

    Do not substitute another type of dressing for NPWT sponges. Without thorough testing, another medium could cause harm to the patient or delay wound healing (see Risk Management Issues with NPWT ).

    RISK MANAGEMENT ISSUES WITH NPWT

    The system used for negative pressure wound therapy (NPWT) is meant to be just thata system whose components are designed to work together. The NPWT system has been approved by the Food and Drug Administration (FDA) to treat a variety of chronic, acute, traumatic, subacute, and dehisced wounds. In general, the system is relatively easy to use and tolerated by patients.

    Some institutions, however, are using alternative means of supplying negative pressure. These variations on the FDA-approved system have the potential to injure patients, thus putting the institution and individual clinicians at risk for liability. The following discussion focuses on the variations that have been reported anecdotally and why these variations could jeopardize patient safety.

    Control of pressure levels

    Instead of the computerized therapy unit that is part of the NPWT system (and which must be rented), wall suction and portable suction devices are being used to provide negative pressure. Wall suctionin which negative pressure is delivered through a stationary unit mounted to a wallis appropriate in many clinical situations; however, it lacks the control mechanisms needed to provide safe negative pressure for wound care. Many wall suction devices have control panels that are notched to dial in low, medium, or high levels of suction. Others have a control panel with numeric values that indicate pressure averages. In general, neither style can be adequately regulated to deliver a precise amount of subatmospheric pressure, which is important in providing the maximum benefits of NPWT and maintaining vascular decompression. Standard wall suction devices are unable to provide the controlled intermittent suction that stimulates replication of cells via mechanical stretch. Intermittent negative pressure is also an essential component for accelerated cell proliferation.

    Contamination concerns

    There is a high risk of cross-contamination from the backflow seen in low-volume suction lines.1 Bjerring and Oberg2 used a radioactive tracer to gauge the potential of cross-contamination between compressed air and wall suction; up to 17% of the tracer had entered the system. The practice of using the same suction device on wound care patients as is used on respiratory patients could conceivably provide a route for respiratory tract contamination in patients receiving ventilatory assistance with air-oxygen mixtures or suctioning procedures.

    The collection canisters on most wall devices are not designed to provide a closed system. If wound fluid is allowed to stagnate, microorganisms are likely to thrive. Collected body fluids represent an infectious disease component that provides an opportunity for cross-contamination between patients and clinicians.

    The airtight canister on the NPWT system is closed and is considered by the FDA to be a safe device for the collection and limited storage of highly contaminated fluids. The NPWT canister also does not allow backflow. A gel pack, located in the bottom of the canister, absorbs wound fluids and coagulates them, thereby reducing the potential for backflow into the tubing. This same safety feature decreases the risk of environmental exposure when disposing of the canister. A standard wall suction collection canister does not have regulated safety devices to reduce the risk of backflow or spillage.

    Other safety concerns

    Another safety mechanism missing from wall suction devices is a means of alerting the clinician to a malfunction; for example, if the tubing connected to the wall suction device becomes disconnected or the amount of pressure provided by the wall unit is inadvertently changed. If suction is stopped for an extended period of time, the wound could dry out and necrotic tissue would likely collect on the wound base. The NPWT therapy unit has a built-in alarm system that alerts the clinician when therapy is discontinued, the airtight seal is broken, or the unit is tipped. These safety features allow the clinician to respond quickly to any problems that would alter or halt pressure.

    The NPWT canister has a limited capacity; it will hold 280 mL of wound fluid. It also is designed to alert the clinician when 280 mL of fluid has been evacuated from the wound. Wall suction devices lack a similar alarm system, and anecdotal reports from clinicians using wall suction and a standard collection canister (which may hold up to 1500 mL of liquid) include descriptions of exsanguination resulting in serious patient injury and death.

    Wound bed concerns

    The NPWT system includes a medical-grade foam sponge that is placed in the wound to help promote healing. In some institutions, an alternative means of interfacing with the wound bed is used. One case study, for example, indicated that the authors used a sterile iris mattress in place of the foam sponge.3 The report did not list the manufacturer of the mattress used in the study, but the report depicts an egg crate design. Although the iris mattress may be similar in appearance to the open-celled polyurethane foam sponge used in NPWT therapy, they are not biochemically comparable. The structural makeup of the NPWT polyurethane sponge adheres to all applicable requirements imposed by the FDA in accordance with biochemical substances. The materials used in the construction of polyurethane foam are identical to those used in blood filtration systems. An iris-type mattress is very dense foam made from a variety of products, none of which were intended to be placed in the body or used as a topical covering for wounds. The density of a foam-type mattress will hamper the ability of subatmospheric pressure to stimulate the wound and may facilitate bacterial growth. Because the makeup of the iris mattress product is unknown, the untested foam may also pose an allergy risk.

    Following guidelines

    Clinicians have a responsibility to follow established guidelines when using a medical device to ensure efficient care and reproducible positive outcomes. The use of substandard, untested replacements for delivery of NPWT can put patients at risk of potential injury or death.

    It is likely that variations of negative pressure wound therapy will find way into the health care marketplace. The manufacturer of the current NPWT system is in the final stages of clinical testing on an advanced therapy system model. The added features are reported to include a larger canister size, increased pressure sensitivity, and more user-friendly controls. In addition, it is likely that other companies will attempt to design a device that can deliver the therapy safely and efficiently. Regardless of what may seem to be 'like' alternatives, for this or any other medical therapy or treatment, these devices should have FDA clearance prior to use on a patient.

    9. Size and trim the drape to cover an area around the wound large enough to secure the foam and to maintain an airtight seal.

    Excess drape can be used to patch air leaks. Other types of film dressings can be used to patch small leaks, but the majority of the wound should be covered with the NPWT adhesive dressing to provide the most appropriate wound environment for healing with subatmospheric pressure.

    10. Gently place the foam into the wound cavity, covering the entire wound base, sides, tunneling, and undermining.

    If a polyurethane foam sponge is being used, any exposed tendons, nerves, or blood vessels must be protected. This can be accomplished by moving available muscle or fascia over the exposed structures or by placing a layer of nonadherent dressing over them. NPWT is not recommended if the dressing must be placed directly on or in direct contact with exposed arteries or veins. Precautions should be taken when placing the dressing in proximity to blood vessels, especially those in a weakened or compromised state.

    NPWT dressings can, however, be used over orthopedic hardware. Hardware may not have to be removed in the presence of an infected wound. Serial quantitative cultures and diligent assessment must be continued throughout treatment to monitor the progress of infection.

    11. Apply tubing to the foam.

    Tubing can be laid on top of the foam or placed inside of the foam. The tubing should be positioned away from direct contact with bony prominences, organs, and blood vessels. In a deep wound, the tubing should be repositioned frequently to minimize pressure on the edge of the wound. The skin can be protected under the tubing with excess foam or a hydrocolloid dressing. Avoid positioning the patient on the tubing to reduce the risk of pressure ulcer formation.

    12. Cover the foam and an area of surrounding healthy tissue with the NPWT adhesive drape to accomplish an airtight seal.

    Lift the tubing and pinch the drape beneath it where it interfaces with the skin. This will reduce undue pressure on the skin. The tubing should be positioned in an area that is least likely to receive pressure from repositioning the patient.

    Fragile periwound skin can be covered with a skin barrier, such as a hydrocolloid, and the drape can be secured directly to the barrier. If the patient's skin is irritated by frequent drape removal, the drape can be cut around the foam, the foam removed, cleansing performed, the new foam placed, and the new drape placed on top of the old one. This will help to reduce the pull caused by completely removing the adhesive drape at each dressing change.

    Do not stretch the drape and do not compress the foam in the wound with the adhesive drape. Simply cover the foam and secure a seal that will minimize tension or shearing forces on the periwound skin.

    13. Attach the tubing from the wound to the tubing in the canister placed in the computerized vacuum therapy unit, ensure clamps are unclamped.

    14. Program the appropriate pressure and cycle in the computerized unit and begin therapy.

    Table 2 lists recommended guidelines for target pressures and cycles for different types of wounds.

    Table 2. SUBATMOSPHERIC PRESSURE RECOMMENDED GUIDELINES

    *Consult treating physician for individual patient conditions and treatment protocols. Consult device user manual and recommended guidelines for details before use.

    Wound Type Rationale for Use Initial Cycle Subsequent Cycles Target Pressure Poly-
    urethane
    Target Pressure Polyvinyl-
    alcohol
    Dressing Change Interval
    Acute/traumatic wound Edema removal, wound contraction, granulation growth, protection from outside contaminants Continuous for first 48 hours Intermittent (5 min on/2 min off) for duration of therapy 125 mm Hg 125-175 mm Hg Every 48 hours (every 12 hours with untreated infection)
    Surgical wound dehiscence Edema removal, wound contraction, granulation growth, protection from outside contaminants Continuous for first 48 hours Intermittent (5 min on/2 min off) for duration of therapy 125 mm Hg 125-175 mm Hg Every 48 hours (every 12 hours with untreated infection)
    Meshed graft Edema removal, adhere graft to wound bed, protect against shearing forces Continuous Continuous for duration of therapy 75-125 mm Hg 125 mm Hg; titrate up for more drainage None; remove dressing after 3-5 days when using either type of foam
    Pressure ulcer Granulation tissue growth, edema removal, wound contraction, moist healing environment , protection from outside contaminants Continuous Intermittent (5 min on/2 min off) for duration of therapy 125 mm Hg 125-175 mm Hg; titrate up for more drainage Every 48 hours (every 12 hours with untreated infection)
    Chronic ulcer (diabetic/arterial vascular) Edema removal, granulation tissue growth, enhance epithelial cell migration, provide moist wound healing, protection from outside contaminants Continuous Continuous for duration of therapy 50-75 mm Hg 125-175 mm Hg; titrate up for more drainage Every 48 hours (every 12 hours with untreated infection)
    Fresh flap Surgical/wound drainage removal underneath sutures, promotes flap adherence to wound base, helps immobilize flap, protects from contaminants Continuous Continuous for duration of therapy 125 mm Hg 125-175 mm Hg; titrate up for more drainage Every 72 hours (every 12 hours with untreated infection)
    Compromised flap Edema removal, granulation tissue growth, adherence of flap Continuous Continuous for duration of therapy 125 mm Hg 125-175 mm Hg; titrate up for more drainage Every 48 hours (every 12 hours with untreated infection)

    Conclusion

    Before any wound care modality is used, the clinician must understand how the modality assists in wound healing and when it should be utilized. Modern health care exists in a litigious society. When a problem occurs during any type of medical treatment, there is often someone looking to place blame.

    In addition, the off-label use of any medical product comes with associated risks. Although many anecdotal reports claim successful use of the NPWT outside manufacturer guidelines, the final responsibility and liability falls on the prescriber.

    By relying on evidence-based practice to deliver care, the clinician has reliable data to support the decision-making process and resulting interventions. When practice varies from the norm and is based on unsubstantiated practices, the clinician puts the patient at risk for substandard outcomes. Health care providers are responsible for delivering the best care to the patient at the most reasonable cost. If a reduction in cost is the only motive for the choice of a procedure, health care providers may be liable for the results.

    Negative pressure wound care therapy has been proven to be a safe, cost-efficient modality for the treatment of wounds. The evidence-based practice guidelines that describe appropriate use of NPWT should be adhered to. Alternative, untested forms of pressure delivery, fluid collection, or wound interface materials can be dangerous to the patient and place the clinician at risk for liability.

    (See Cost Considerations).

    COST CONSIDERATIONS

    Wound care is an expensive endeavor. Pressure ulcers alone are a significant complication of hospital patients that can result in high treatment costs ranging from $2000 to $70,000 per wound.1 Moreover, the financial cost surrounding treatment does not begin to quantify the human cost of a nonhealing wound.

    NPWT may reduce expenses related to wound care through a decrease in the number of dressing changes required. In addition, the amount of skilled nursing time needed to perform dressing changes is reduced, patients can be transferred more quickly to less acute and less expensive care settings, and healing times are faster with NPWT when compared with saline-soaked gauze. In 1999, the Weinberg Group, Inc, performed a cost-effectiveness analysis based on data from clinicians, Medicare charges, and providers. They found that the long-term cost of NPWT was lower and outcomes were better when compared with standard wound care methods.2 Another study concluded that in the home care setting, NPWT could cost payers an estimated 38% less and heal some pressure ulcers 61% faster than saline-soaked gauze dressings.3 ECRI, a nonprofit health services research agency and a collaborating center for the World Health Organization for health care technology assessment, has stated that despite the advent of numerous types of dressings, saline-soaked gauze remains the most prescribed dressing in the acute care and home care settings.4

    Direct comparison of NPWT to a particular type of dressing would be difficult because it is unlikely that a single dressing type would be appropriate throughout the entire healing process. On the other hand, NPWT can be used throughout wound healing for a variety of wound conditions. More controlled clinical trials are needed to definitively prove that NPWT is a less-expensive wound care modality; however, enough clinical evidence has been produced to elicit reimbursement by Medicare.

    For an expanded version of this article, visit our Web site, http://www.woundcarenet.com.

    BY SUSAN MENDEZ-EASTMAN, RN, CWCN, CPSN
    Wound Care Nurse
    Nebraska Health System
    Omaha, NE

    Source:  New NursingCenter http://www.nursingcenter.com/

    References

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    2. Vandenbrugh H. Mechanical forces and their second messengers in stimulating cell growth in vitro. Am J Physiol 1992;262:R350-R355.

    3. Wirtz H, Dobbs L. Calcium mobilization and exocytosis after one mechanical stretch of lung epithelial cells. Science 1990;250:1266-9.

    4. lizarov G. The tensio-stress effect on the genesis and growth of tissues. Part II. The influence of the rate and frequency of distraction. Clin Orthop Rel Res 1989;239:263-85.

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    8. Morykwas M, Argenta L, Shelton-Brown E, McGuirt W. Vacuum assisted closure: a new method for wound control and treatment: animal studies and basic foundation. Ann Plast Surg 1997;38:553-62.

    9. Stotts N. Wound infection: diagnosis and management. In Bryant R, ed. Acute & Chronic Wounds: Nursing Management. St Louis, MO; Mosby; 2000.

    10. Hunt T. The physiology of wound healing. Ann Emerg Med 1988;17:1265-73.

    11. Bergstrom N, Bennett MA, Carlson CE, et al. Treatment of Pressure Ulcers. Clinical Practice Guideline, No. 15. AHCPR Publication No. 95-0652. Rockville, MD: Agency for Health Care Policy and Research; December 1994.

    References Cost Considerations

    1. Gallager SM. Outcomes in clinical practice: pressure ulcer prevalence and incidence studies. Ostomy Wound Manage 1997;43(1):28-32, 34-5.

    2. Weinberg Group, Inc. Technology assessment of the V.A.C. for in-home treatment of chronic wounds. Washington, DC: Weinberg Group, Inc; May 1999; p 61.

    3. Philbeck, Jr TE, Whittinton KT, Millsap MH, Briones RB, Wight DG, Schroeder WJ. The clinical and cost effectiveness of externally applied negative pressure wound therapy in the treatment of wounds in home healthcare Medicare patients. Ostomy Wound Manage 1999;45(11):41-50.

    4. ECRI. Occlusive dressings for the treatment of chronic wounds [technology assessment report]. Plymouth Meeting, PA: ECRI; Feb 2000; p 141.

    References RISK MANAGEMENT ISSUES WITH NPWT

    1. Miller C. 'Back flow' in low-volume suction lines may lead to potential cross-contamination. RDH 1996;16(1):30.

    2. Bjerring P, Oberg B. Possible role of vacuum systems and compressed air generators in cross-infection in the ICU: a radioactive tracer study. Brit J Anesth 1987:59:648-50.

    3. Blackburn J, Luciano B, Hall W, Jeffords K, Hauck R, Banducci D, Graham W. Negative pressure dressings as a bolster for skin grafts. Ann Plast Surg 1998;40:453-7.