NPWT is indicated for vacuum assisted drainage for patients who would benefit from a suction device to promote wound healing. The huge challenge to the healthcare system of treating acute, chronic, and complicated wounds, makes cost effectiveness and efficiency of NPWT very important. Patient comfort and compliance are key in optimizing the application of NPWT.
No treatment for serious wounds provides a "one-size-fits-all" solution from injury to healing. New, advanced NPWT equipment and protocols (sophisticated and full-featured, yet flexible and practical) allow for customized treatment approaches for each wound, based on its characteristics during the phases of healing.
It should be noted that NPWT is contraindicated in the presence of:
- Necrotic tissue
- Unexplored or non-enteric fistulas
- Untreated osteomyelitis
- Wounds containing malignant tissue
- Exposed arteries, veins, or organs
Additionally, a core principle of wound management is to properly prepare the wound for closing. That's why it's important to remember that NPWT, as interim therapy, should be discontinued once the condition of a wound is suitable for closing, either spontaneously or surgically.
WOUND HEALING 101
A wound is created when the anatomic integrity of any tissue is disrupted. Wounds are caused by surgery, trauma, or disease, and are acute or chronic. Chronic wounds often are the most difficult to treat as healing may fail to progress because of underlying pathophysiology and other disturbances.
Wound healing involves a series of mechanisms that progress toward restoration of tissue similar to the "status quo" prior to the wound. It progresses continuously in phases, some of which overlap. Each step and component in the healing processes is essential, and cannot be skipped or replaced without delay or prevention of healing. The goal is nearly always the same...to optimize the host and close the wound in the most appropriate way.
Wound healing is a highly specialized and complex subject. Wound management is an art as well as a science. Caregivers must reflect on their growing knowledge and experience, and be ready to incorporate new approaches into their practices.
A systematic approach to wounds yields the best results. Here is what you need to know and think about.
Assessment / Classification
The patient history, physical exam, exploration of the wound and cleansing are important first steps in assessing the patient and the wound.
Wounds are classified as acute or chronic, by etiology, and by various other means. For example, pressure ulcers are typically designated as Stages I-IV (by increasing severity). No matter the classification, the steps to healing are usually the same: prepare the wound bed for healing by removing dead tissue; keep the wound in bacterial balance; fill the defect and cover as quickly as possible; promote the formation and maturation of new tissue to prepare the wound for spontaneous healing or surgical closure.
If the wound contains necrotic tissue, debridement (surgical, mechanical, autolytic or enzymatic) is usually recommended. Exceptions exist depending on wound etiology, the amount of necrotic tissue, wound characteristics, patient status, goals of therapy, and other considerations.
Bacterial control is essential for healing to progress. The extent of infection needs to be rapidly determined. Diagnosis depends on clinical signs of infection, plus culture results to identify bacteria and fungi. Treatment requires topical and/or systemic antimicrobial therapy.
Once the wound is irrigated, cleansed and debrided, wound dressings provide a protective barrier and are critical for filling dead spaces, for delivering antimicrobials, and for maintaining a moist environment.
Therapeutic and adjunctive therapies, such as negative pressure wound therapy, promote healing by creating the appropriate conditions for cell activation and progression through the phases of healing.
Optimizing the Host
Optimizing the host means eliminating systemic and local disturbances. The local factors include tissue trauma, necrosis and infection, removal of foreign bodies, hematomas and dead spaces. Systemic factors are classified as the 3 Ds: Deficiencies, Drugs and Diseases.
Optimizing the host also means providing a physiologic environment conducive to natural healing. Essential are control of drainage and edema, proper pH, gas exchange, protection from contamination, proper moisture balance, and insulation.
Wound closure takes place in several ways. In closure by first intention, wound edges are brought together manually (ex. sutures or staples). In closure by second intention, wounds are left open for drainage and later close spontaneously. In delayed primary healing, or third intention closure, wounds are left open until adequate granulation tissue forms, then allowing for successful surgical closing using a graft or flap.
The economic value of wound care therapies must be well understood in order to properly manage wounds. Prevention of injury and prevention of recurrence are top priorities since the total cost of treating chronic and difficult wounds is high. Patients, caregivers and payors all share an interest in economic factors effecting treatment decisions.
Wound care involves direct costs in dressings, ancillary supplies, equipment, medications, treatments and other interventions, and staff time. Indirect costs include quality of life costs, opportunity costs for patients and caregivers, and costs such as litigation. Economic value needs to be measured against the goals of treatment.
NPWT for vacuum assisted drainage has been shown to reduce expenses through reduced dressing changes and reduced nursing time associated with dressing changes. In addition, less time required for dressing changes may enable patient transfer to lower cost treatment settings. When correctly applied to draining wounds, healing times may be reduced, and the wound may be prepared for earlier closure.
Reimbursement rules for NPWT must be carefully taken into account to determine qualification for coverage.
The PRO Series™ is reimbursable under most third party payer plans. If you have questions regarding coding or billing, you should contact your payor.
Below are the HCPCS codes for the Prospera® Negative Pressure Wound Therapy System:
|Prospera® PROSeries™||E2402||Negative pressure wound therapy electrical pump, stationary or portable|
|Prospera® Dressing Change Kit||A6550||Dressing set for negative pressure wound therapy electrical pump, stationary or portable, each|
|Prospera® Canister||A7000||Canister, disposable, used with suction pump, each|
BENEFITS OF LOWER NEGATIVE PRESSURE AND INTERMITTENT THERAPY
Despite widespread use of NPWT in recent years, questions have remained about pressure intensity levels, duration of treatment, and treatment intervals. Two studies published by Wackenfors, et al, in 2004 and 2005, respectively, explored the effects of NPWT on microvascular blood flow using laser Doppler in pig wound models. Both studies shed light on the questions above.
The first, a study of inquinal wounds using pressures of -50 to -200 mmHg, noted increased blood flow closer to the wound in muscular versus subcutaneous tissue. A hypoperfused area where blood flow decreased was found in the immediate proximity of the wound edge. The area of hypoperfusion increased with the use of higher negative pressures and was especially prominent in subcutaneous tissue. The results suggested negative pressures of -100 mmHg be used in muscular tissue and -75 mmHg in softer subcutaneous tissue, to "minimize possible ischemic events." Blood flow increased multifold when therapy was terminated, suggesting that intermittent therapy may provide additional benefits in blood flow and wound healing.
The second study examined the effects of NPWT on peristernal soft tissue blood flow and metabolism (pressures of -50 to -200 mmHg) in an uninfected porcine sternotomy wound model. As in the first study, the peak increase in blood flow occurred closer to the wound edge in muscular versus subcutaneous tissue. In immediate proximity to the wound, a zone of relative hypoperfusion increased with increasing negative pressure. Wound fluid partial pressure of oxygen and lactate levels (in combination considered important to healing) increased when NPWT was applied.
The Wackenfor studies suggest that lower negative pressures than traditionally applied in NPWT may strike the best balance between optimizing perfusion and preventing ischemia. In addition, they clearly point out the importance of being able to adjust negative pressure to the type of tissue and the benefits of intermittent therapy.
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