ADVANCED WOUND CARE MODALITIES

Advanced therapies, also known as adjunctive therapies, are used when standard wound care is not sufficient to bring about wound healing. Advance therapies include negative-pressure wound therapy, hyperbaric oxygen therapy, and bioengineered skin products (Baranoski & Ayello, 2020).

Negative-Pressure Wound Therapy (NPWT)

Negative-pressure dressings (also called vacuum-assisted closure devices or sub-atmospheric-pressure dressings) are labor-saving devices that remove excess fluid from wounds while improving healing time (Shah et al., 2018). NPWT can be used in both acute and chronic wound care. Prior to applying NPWT, the wound bed must be free from necrotic tissue and infection under control (being actively treated).

Typically, NPWT is used for full-thickness wounds that require granulation tissue growth and contraction. It is the recommended treatment for stage 3 and stage 4 pressure injuries (Baranoski & Ayello, 2020).

NPWT has become the primary treatment used by military surgeons and trauma surgeons treating complex wounds such as penetrating trauma, fasciotomy incisions, and open fractures. For patients who require split-thickness grafts, NPWT has taken the place of established bolster dressings as the optimum means for preserving close interaction between the graft and the underlying wound bed (WOCN, 2022).

There are several types of NPWT systems; all systems are based on either foam or gauze dressings. Whichever type is used, the dressing is fitted into the wound and covered by a special plastic film. A suction tube is applied through a hole made in the film and connected to the sponge or gauze via a disc. When the NPWT unit is turned on, a vacuum is applied to the tube, and it continuously sucks fluid from the wound. The vacuum also pulls the plastic film tightly over the top of the wound, sealing the wound from the environment, protecting the wound from outside contaminants, and keeping the wound warm.

For complex wounds, it may be necessary to continue use of negative pressure for several weeks. NPWT dressings are usually changed every 48 to 72 hours and sometimes more frequently for heavily infected wounds or heavily exudating wounds, depending on physician orders.

In addition to removing excess wound fluid, reducing the growth medium for bacteria, and removing wound inhibitory factors, a negative-pressure dressing encourages contraction of and granulation around the wound, thereby reducing edema, supporting development of local circulation, and providing more oxygen and nutrients to the cells.

The pull of negative pressure on cells has been demonstrated to stimulate new cell growth. Studies show NPWT to be very effective early in treatment of deep pressure injuries by reducing the depth of the ulcer via granulation and also as an aid to healing of chronic pressure injuries. Research indicates that granulation tissue develops more quickly with intermittent rather than continuous therapy, however continuous therapy is needed when there are high volumes of drainage. Studies also show that NPWT significantly increases healing rates and decreases healing time in diabetic foot ulcers and decreases the frequency of major amputations (Borys et al., 2019).

NPWT can be used along with instillation of solutions into the wound bed. Several different solutions can be used, including normal saline and hypochlorous acid, with the intent to clean and irrigate the wound and to diminish bacterial colonization on the wound bed. This therapy is only available for hospitalized patients at this time (Baranoski & Ayello, 2020).

NPWT can be safely used in children older than one year. In the pediatric population the pressure setting are modified and the therapy closely monitored by the wound clinician (WOCN, 2022).

SPECIAL CONSIDERATIONS

When using NPWT, some special considerations must be kept in mind:

• Painful dressing changes can be prevented by placing a contact layer next to the wound bed beneath foam dressings (with prior physician/surgeon approval). If foam is adherent to the wound bed, it can be soaked with normal saline for a few minutes prior to removal, allowing it to be removed more easily. As well as decreasing pain, both these measures reduce the likelihood of causing wound bleeding.
• If tunneling is present, the wound is packed loosely with white foam (if a foam system is being used). This hydrophilic foam does not fall apart easily, reducing the possibility of unintentionally leaving a piece of foam in the area of tunneling.
• Special care is taken to protect the periwound area. This can be done using spray-on skin sealants or “picture-framing” the wound edges with strips of hydrocolloid dressings.
• Most NPWT devices have two settings: continuous suction or intermittent suction. Continuous suction is recommended at the beginning of therapy, and it is also the most appropriate setting for heavily draining wounds. Intermittent suction is usually applied when the amount of drainage has decreased and the goal is to enhance the growth of granulation tissue. However, some patients complain of wound discomfort with intermittent therapy.
• NPWT is continued as long as there is evidence of wound healing (i.e., the growth of new, healthy granulation tissue and decreasing wound size). Once a healing wound has filled in with granulation tissue close to surface level, NPWT is discontinued.

Hyperbaric Oxygen Therapy (HBOT)

Adequate levels of oxygen are essential for all phases of wound healing. Hyperbaric oxygen therapy is a process whereby the patient inhales 100% oxygen while inside a pressurized hyperbaric chamber. The delivery of oxygen under pressure increases the amount of dissolved oxygen in the plasma, and this in turn allows for increased amounts of oxygen distribution to the tissues. The goal is to stimulate healing by exposing the wound to high levels of oxygen. Increased oxygen levels also increase leukocyte activity with the destruction of aerobic gram-positive and gram-negative organisms.

The treatment can be delivered in single-unit chambers that accommodate one patient or in multi-unit chambers in which several patients are treated simultaneously. In most instances, HBOT is provided on an outpatient basis. HBOT therapy has an excellent safety record in the United States (Baranoski & Ayello, 2020).

HBOT benefits patients with wounds that are severely infected (e.g., the presence of refractory osteomyelitis) or in cases in which wound healing is impeded by poor circulation. It is used to treat bone infection (osteomyelitis) because the increased delivery of oxygen to the bone has been shown to improve the functioning of white blood cells.

HBOT has also proved to be a positive factor in the healing of diabetic foot ulcers. HBOT is a proven therapy used to decrease the number of major amputations in person with diabetes and concurrent chronic foot ulcers. In one study where persons with diabetes and diabetic foot ulcers received HBOT there was a notably quicker time to wound healing (Baranoski & Ayello, 2020; WOCN 2022).

It is also successfully used to advance the healing of surgical flaps and grafts. However, HBOT is not beneficial to a wound that is covered with necrotic tissue (e.g., dry gangrene).

The first step is a patient evaluation to determine whether the treatment is appropriate. For any patient who has a recent history of malignancy or is being treated for malignancy, a consultation with the treating oncologist is necessary before deciding about HBOT.

Contraindications to HBOT include:

• Untreated pneumothorax
• Ear disorders
• Medications such as doxorubicin (Adriamycin) and cisplatinum
• Claustrophobia
• Seizure disorder (to be determined on an individualized basis, since a side effect of HBOT is oxygen toxicity, which can induce seizure activity)
  (WOCN, 2022)

Bioengineered Skin Products

This is a fast-evolving area in wound care. Such products can be quite expensive, but they offer several advantages, the most important being speedy wound closure. They can also obviate the need for a graft with skin harvested from the patient, usually removed from the thigh area, which produces a second, and many times painful, wound site.

Patients must be carefully selected for this therapy, and their overall health status and ability to heal must be taken into consideration. The wound must be free from infection and the wound bed well vascularized, free of necrotic tissue, and adequately prepared prior to application of the specific skin substitute product. Most facilities require that authorization from the payment source be obtained prior to the treatment.

A key consideration for the wound care team is choosing the product that is most appropriate for the particular wound; this requires expertise, research, and collaboration with other wound care specialists.

Bioengineered skin substitutes can be classified as either cellular or acellular. Cellular products contain living cells. Acellular products contain collagen, usually derived from a porcine or bovine source; they do not contain living cells.

A product made from cryopreserved umbilical cord and amniotic membrane matrix has achieved considerable success in treating complex diabetic foot wounds. It has also been found to have longer duration in the wound bed and may require fewer applications. This also can reduce the cost of treatment (Wound Care Advisor, 2019).

Adjunct Therapies for Wound Care

The following therapies are not used alone but in conjunction with other treatments to heal wounds.

ELECTRICAL STIMULATION THERAPY (E-STIM)

Electrical stimulation therapy is the use of an electrical current to transfer energy to a wound. E-stim is performed by physical therapists and occupational therapists who have training and experience in the use of this therapy.

Effects attributed to e-stim include increased blood flow to the area, which increases oxygen and nutrient transport to the wound, reduced edema and pain, and increased fibroblast and collagen development. It may be useful for pressure injuries, venous ulcers, surgical wounds, donor sites, burn wounds, and others. Studies have shown positive benefits in the treatment of diabetic foot ulcers. E-stim has also been shown to increase the blood supply to ulcer sites and decrease the healing time. This is an area of ongoing research. Studies show that electrical stimulation also has bacteriostatic and bactericidal effects on organisms that are present in chronic wounds.

E-stim for wound care is not to be used in the presence of a cardiac pacemaker, malignancy, osteomyelitis, and when electrodes would be placed near the heart, larynx, carotid sinus, eyes, head, and some other areas. E-stim therapy should not be used when there is a possibility of basal cell or squamous cell carcinoma in the wound or the surrounding tissues. E-stim is contraindicated for individuals with infections (Baranoski & Ayello, 2020; WOCN, 2022).

ULTRASOUND

Noncontact low frequency ultrasound has been shown to reduce wound size and “bio-burn.” In this modality, a trained, experienced clinician employs the ultrasound machine to vaporize normal saline into microdroplets that are then propelled into the wound bed (Cordrey, 2016).

Ultrasound is used to increase the elasticity of collagen, decrease muscle and joint stiffness, decrease pain and muscle spasms, decrease edema, increase oxygen transport, and accelerate wound healing. Ultrasound stimulates circulation to the treated area, which aids in cell metabolism. It also provides for an increase in macrophage activity and leads to increased protein production by fibroblasts.

Ultrasound is used on chronic wounds, pressure injuries, venous ulcers, and trauma wounds. It is not indicated in cases of infection, osteomyelitis, profuse bleeding, severe arterial insufficiency, or necrotic wounds.

Ultrasound therapy cannot be used over the following areas of the body:

• Eyes
• Heart
• Carotid sinuses
• Uterus during pregnancy
• Exposed central nervous system (e.g., a laminectomy site)
  (Baranoski & Ayello, 2020)

IASTM

Instrument-assisted soft tissue mobilization (IASTM) is a therapeutic approach used by physical therapists to treat fascial dysfunction and pain. The trained therapist uses specialized handheld instruments to apply force to small specific areas. The intent of treatment is to initiate an inflammatory healing reaction, with subsequent production of collagen and healing. Benefits of IASTM include increase in strength and diminished pain (Eastpoint Natural Health, 2020).