September 26, 2022 admin
Negative pressure wound therapy (NPWT)
Wounds are part of our life, and we receive them anywhere anytime, like cooking, driving, walking, working, or slipping. Generally, they heal on their own or with help of little medical assistance. But some wounds need more care and attention. Some wounds are complex and very difficult to heal. Burns and complex surgeries are some reasons for such complex, chronic wounds. The aging population and the increasing number of diabetes and obesity are creating a rapid incidence of chronic wounds. These wounds are difficult to treat and require a longer period to heal.
Cotton gauzes have been the main wound dressing material and are used frequently. Gauze is an inexpensive product, which absorbs exudates and keeps wounds clean, for simple wounds. Flaps or free tissue transfer therapies can help treat complex wounds, but the treatment is complex, requires specialized surgery, has higher complication rates, and leaves scars.
Wounds kept under moist conditions heal faster. This revelation changed wound dressing practices entirely. Keeping the wound clean and moist is the key factor in wound treatment. This has led to the development of thousands of products in the wound care segment. But a method, which can stimulate the natural ability of wounds or the body to heal, is always very valuable to the patient. Newer treatments keep emerging helping wound care practitioners. Negative pressure wound therapy is one of such ingenious and affordable wound care treatments which is effective in treating complex, chronic or acute wounds.
What is negative pressure wound therapy or NPWT?
This therapy is also called Vacuum-assisted Wound Closure therapy. It is a dressing system that applies a sub-atmospheric pressure to the surface of a wound intermittently or continuously. This method helps the natural healing mechanism of the tissues.
Argenta and Morykwas introduced this new method in the 1990s. They tried this on 300 wounds, chronic, sub-acute, and acute, out of which 296 responded with very positive results. These wounds were treated until completely healed. Observations recorded that this technique removes chronic edema. This results in increased localized blood flow. Applied forces help enhance the formation of granulation tissues. This confirms that Negative Pressure wound therapy or Vacuum-assisted closure is an extremely effective method for treating chronic or complex wounds.
This method uses special devices which generate pressure or suction as per need and advice by experts. Observations from the Animal studies indicate that:
• This method optimizes blood flow in the wound area
• It removes excessive fluid which slows cell growth
• It decreases the number of bacteria
• It also decreases local tissue swelling
Also, intermittent low pressure causes an increased rate of cell division and formation of granulation tissues.
Devices and Instruments used in Negative Pressure Wound Therapy
Many systems and dressing options are now available commercially nowadays. Right from systems for patients with limited mobility or complex wounds to lightweight, battery-powered units, a variety is available in the market as per requirement. These systems use many accessories during the procedure.
It requires a special kind of foam dressing which is cut to the size of the wound. Then it is placed over the wound. A drain tube is placed over the foam dressing and the foam, the tip of the tube and healthy skin around the wound is covered with special adhesive tape. The other end of the drain is connected to the negative pressure unit. This unit is specially programmed to manage the necessary pressure. Once the unit is switched on, it sucks air out of the dressing foam. This collapses the foam inwards and edges of the wound with it. The fluids in the wound are absorbed by foam and transported into the disposable canister through drain tube.
It is recommended to change Negative-pressure wound therapy dressings every 48 hours. In case of infection, the dressing should be changed every 24 hours. If the wound is not infected, it may be possible to leave the dressing on for longer periods. The duration of the therapy varies from 2 to 6 weeks, depending on the type of wound.
Appropriate conditions to use Negative Pressure Wound Therapy
Negative Pressure Wound Therapy is used mainly for complex wounds. It is advised by the experts in the following conditions:
• Acute Surgical and Traumatic Wounds
• Acute, and sub-acute wounds
• Chronic and open wounds
• Pressure ulcers
• As an adjunct to skin grafts or flap procedures
• Meshed Grafts (to secure the graft in place)
• Various Ulcers like Venous Stasis ulcers, Lower extremity ulcers
This method is not suitable for:
• Fistulas to organs and body cavities
• Necrotic tissues (Dead Tissues)
• Inflamed bones or Osteomyelitis
• Wounds inflicted due to skin cancer
Effectiveness of Negative Pressure Wound Therapy
When compared with conventional wound therapy, Negative Pressure Wound Therapy shows effectiveness in following:
• Better healing in patients with diabetes mellitus
• Better healing of transplanted skin
• Better healing in gangrene which leads to amputation
• Less infection in open wounds inflicted by open fractures
This method is less effective in:
• Open abdominal wounds
• Fournier Gangrene
• Tissue defects after some types of surgeries
What are the benefits of Negative Pressure Wound Therapy to the patients?
• Less time in the hospital. Earlier discharge
• Fewer requirements of Surgery
• Fewer wound dressing changes
• Improved quality of life
What are the disadvantages of NPWT to the patients?
• Application of negative pressure causes pain initially
• The patient needs to be hooked to the treatment system for almost a day
• It is not effective on all types of wounds. Some wounds may require other effective treatments
What are the possible complications of Negative Pressure Wound Therapy?
No treatment is completely safe. Though Negative Pressure Wound therapy is a good method, it may cause complications sometime. Here are some complications that may arise due to Negative Pressure Wound Therapy:
• Injury to the skin around the wound
• Growth of granulation tissue into the foam dressing
• The adhesive tape used can cause contact dermatitis
• Formation of Fistula
• Pressure Necrosis
• Increased pain due to reduced pressure
• Development of skin cancer
• Experts strongly advise stopping Negative Pressure Wound Therapy in the following conditions
• If the wound is not healing
• Found Pus in the dressing or the canister
• Intolerance to the treatment
• Blood Clots or uncontrolled bleeding under the dressing
Is Negative Pressure Wound Therapy affordable?
Considering the positive sides of the therapy and less hospitalization, and lack of surgical processes, the cost of Negative Pressure Wound Therapy is similar to conventional treatments. Economic advantages or disadvantages may vary depending on the case, wound, and patient’s history.
Negative Pressure Wound Therapy is a very affordable, effective, and efficient alternative to conventional wound care methods. It has its drawbacks, but mostly it is a very positive treatment, especially for patients suffering from chronic wounds. This method will improve with time and provide more and more reliable, affordable and clean solutions for wound care.