Wound Care and Methods of Debridement
Debridement is one of the cornerstones of effective wound care and has been demonstrated to be one of the most important variables in wound healing time. Assessment of tissue types, removal of nonviable tissue, and appropriate wound treatments are all critical for optimal healing.
Wound Bed Tissue
The health of the wound bed is a big determinant of the healing process and treatment plan. The ideal wound bed is covered with granulation tissue. Even exposed bone or tendon will granulate if the healing process is unimpeded.
Necrotic tissue in the wound bed slows healing and increases the risk of infection; non-viable tissue is typically heavily colonized with bacteria. Most necrotic wounds should be debrided in some way to reduce infectious risk to the patient.
It is easy to see why large amounts of necrotic tissue should be removed, but what about wounds with small amounts of necrosis? Even small amounts of necrotic tissue impact wound healing. While there is a much smaller increased risk of infection, the wound risk often has more to do with the health and inflammatory state of the wound bed than overt infection.
Presence of dead cells results in increased inflammation in the wound bed. Necrotic cells can release tumor necrosis factor, which increases the rate of adjacent viable cell death. This inflammatory milieu also diminishes macrophage and fibroblast function critical for healing. Damage-associated molecular patterns (DAMPs) are intracellular materials released from the cells of necrotic tissue that also increase inflammation. These DAMPs cause nearby cells to release pro-inflammatory cytokines, chemokines, and adhesion molecules, which contribute to the exaggerated inflammatory response. All of these processes interfere with wound healing.
Methods of Debridement
These are six methods of wound debridement.
Enzymatic debriding agents use enzymes to remove nonviable tissue over a period of days or weeks. The only enzymatic agent available in the USA today is collagenase, or Santyl. Collagenase works by cleaving denatured collagen strands in necrotic tissue. The collagen byproducts aid in healing by stimulating fibroblast, keratinocyte and endothelial cell migration to the wound bed. Many physicians use enzymatic debridement in conjunction with sharp tissue removal.
Enzymatic debridement is quite easy to use, typically painless, and does not damage healthy tissue. The factors limiting its use are primarily expense and speed. A wound with necrotic tissue that must be removed quickly requires more active debridement than waiting for the collagenase to loosen and remove the tissue. Good stewardship of limited financial resources may limit the use of more expensive treatment options such as collagenast.
Surgical or Sharp
Biofilm is an often-invisible tissue layer that stalls wound healing. A biofilm is a consortium of bacteria living in extracellular polymeric substances, or EPS. EPS are polysaccharides, proteins, extracellular DNA (eDNA), and lipids. Bacteria in the biofilm are protected from adverse environmental factors and immune response by the EPS, making them virtually impervious to most wound treatments and antibiotics. While there are many cleansing solutions and topical wound products that help manage biofilm, the best way to remove it is to superficially debride the wound bed. Use of some dressing materials can be very helpful in minimizing or slowing reaccumulation, such as silver products, surfactant wound care gel, cadexomeric iodine gel, and sodium hypochlorite products. (Not an exhaustive list.)
Wound Treatment Options
Adjunctive Treatment Options
- Electronic stimulation, or E-stim, involves the use of mild electrical pulses that mimic neuronal impulses. This stimulates blood flow and angiogenesis, thereby increasing capillary density and perfusion, improving wound oxygenation, and encouraging granulation and fibroblast activity.
- Diathermy (or pulsed, short-wave diathermy) is the application of shortwave (10 to 100 MHz frequency) electromagnetic energy to the wound tissue. The energy is applied at nonthermal levels and is thought to primarily impact the cellular manufacture of ATP and proteins. It also impacts growth factor activation in fibroblasts and nerve cells, macrophage activation and changes in myosin phosphorylation.
- Ultrasound therapy is administration of a high frequency ultrasound to the wound to promote healing. The ultrasonic energy has a vibratory effect on cells and is thought to reduce inflammation and increase tissue perfusion. Although therapeutic ultrasound has been used to aid in the healing of chronic wounds, no consensus exists regarding its effectiveness.
Resources and References
- Mil Med Res. 2015; 2: 12.
Published online 2015 May 19. doi: 10.1186/s40779-015-0039-0
Programmed cell death and its role in inflammation
The inflammatory response to cell death
- March 1, 2003
Vol. 6 •Issue 2 • Page 86
Diathermy for Wound Care
By Michelle H. Cameron, PT, OCS