Chronic Wounds: A Continuing Challenge

We enjoyed reading Dr Keith Harding’s article on the value of moist dressings for chronic wounds (CONSULTANT, March 2012, page 214), but we feel that some of his comments do not give the full spectrum of challenges one may encounter with a wound of this type. His article implies that chronic wounds are known for their copious exudate production. To manage these wounds, Dr Harding states that there needs to be a fine balance between controlling the amount of exudates produced from the chronic wound while ensuring a moist environment is maintained over the wound base. This is needed to promote collagen synthesis and granulation tissue.

We feel this explanation is only partially correct for managing all chronic wounds. Because many chronic wounds do not generate any significant exudate, moisturization of the wound base is of primary importance. Conversely, some wounds are so exudative that bioburden management and moisture barrier control are the prime interventions for their management. Thus, wound base moisture management must be based on clinical assessment.

Furthermore, managing a chronic wound before addressing the reason the wound is not healing violates a fundamental wound healing principle. The principle is that all chronic wounds must be evaluated and managed, as a starting point, by correcting the reason(s) the wound is failing to improve. In our experiences, there are three primary reasons why the majority (more than 90%) of chronic wounds fail to heal. This triad of conditions includes:

•Unresolved infection (eg, osteomyelitis).

•Underlying deformity.

•Ischemia/hypoxia.

We have coined the term the “treacherous triad” for these three reasons chronic wounds fail to heal.

Once the triad components are addressed, then consideration for advanced therapies which include bioengineered wound covering agents, growth hormones, platelet-rich plasma, acupuncture, electrical stimulation, ultrasound therapy, matrix metalloproteinase inhibitors, laser light treatments, and near infra-red light therapy can be considered. The reasons to consider advanced therapies are for the reasons Dr Harding gives for the benefits of maintaining a moist wound base, namely improving collagen synthesis, permitting granulation tissue formation, enhancing cell migration and promoting epithelialization, increasing concentrations of matrix metalloproteinases, augmenting bacteriostatic and bactericidal components of wound fluid, and finally neutrophil attraction to the wound. We do not consider negative pressure wound therapy/sub-atmospheric wound dressing (NPWT/SAWD) and hyperbaric oxygen (HBO) therapy as advanced therapies because their use is quantifiable and well documented. For example, studies show NPWT/SAWD controls moisture in the wound environment, removes exudates, promotes wound contraction, and stimulates fibroblast function.^1-3

Indications for HBO therapy are quantifiable by measuring juxta-wound oxygen tensions. If they are below the level that would predict healing, ie 30 mm Hg, but improve to over 200 mm Hg with a HBO exposure, the positive predictive value for healing approaches 90%.⁴

We want to thank Dr Harding for providing an excellent summary of the different occlusive dressings clinicians have the option of selecting to maintain an appropriate moist wound environment. However, one cannot advance to the management of chronic wounds through the use of any of these modalities without first assessing the reason the chronic wound is not healing.

——
Lisa Nhan, DPM
Michael B. Strauss, MD
Long Beach Memorial Medical Center
Long Beach, Calif