Refractory wounds comprise a significant worldwide health problem. Wounds that fail to heal not only impact quality of life but also impose a significant physical, psychosocial, and financial burden. Additionally, individuals with refractory wounds often experience significant morbidity and sometimes mortality. Wound infections and amputations are common in this population, and chronic conditions often exist as well.
Definition of Refractory Wounds
By definition, refractory wounds are chronic wounds that do not respond normally to treatment. A wound is considered refractory if there is no improvement within two to four weeks of implementing an evidence-based plan of care. Wound size and duration are predicative factors for wound healing. Ninety percent of all non-healing wounds have been identified as diabetic or neuropathic wounds, pressure injuries, or wounds of venous etiology, and they are often multifactorial.
Identifying Wound Etiology and Causative Factors
We’ve all seen and cared for wounds that just won’t heal. When developing an evidence-based plan of care for wound management, it is important first to determine wound etiology. We cannot effectively heal something if we don’t know the cause. Wound etiology guides treatment, and determining the cause of a wound is an important first step in putting together an evidence-based plan of care for treatment and prevention of wound recurrence.
Once wound etiology is determined, we must try to correct the identified causative factor. If it cannot be fully corrected, the plan of care will need to be adjusted. Supportive, evidence-based topical treatment with an individualized plan of care is key to successful wound management. An inability to correct etiologic factors will lead to impaired healing. A bedbound patient with an inconsistent turning schedule and a diabetic patient with inconsistent offloading of the plantar surface are examples of patients in whom healing would be impaired and the etiologic factor is not fully corrected. It is important to remember that a biopsy should be considered whenever a wound is non-healing and the reason for failure to heal is unclear.
Systemic factors affecting repair are commonly categorized into four parts: intrinsic, extrinsic, iatrogenic, and adherence. In this blog, we will focus on intrinsic factors affecting repair and thereby contributing to a refractory wound.
Intrinsic Factors in Wound Healing
Intrinsic factors are those belonging to the patient, and they include both modifiable and non-modifiable factors. The patient’s comorbidities and physical and physiologic conditions that impact wound healing are classified as intrinsic factors. Some examples include age, the presence of chronic illness, tissue perfusion and oxygenation (also related to chronic disease), immunosuppression (autoimmune diseases and medications that can suppress the immune system), and neurologic impairment (spinal cord injuries are common here).
As discussed in prior blogs, older adults are at risk for a multitude of skin issues, skin breakdown, and impaired healing related to aging changes both internally and specifically within the different layers of the skin (thinning epidermis, dermal atrophy, dryness, and reduced elasticity). Additionally, the increased prevalence of chronic illness among older adults contributes to recognizing age as an intrinsic factor affecting wound healing.
Chronic illnesses also contribute to refractory wounds as an intrinsic factor. Diabetes, heart disease, cancer, vascular disease, and neuropathic diseases are all examples of chronic illnesses that may cause a delay in healing for a multitude of reasons. Blood flow and tissue perfusion, sensory perception, and adequate oxygenation are all important factors to consider when looking at the healing process.
Perfusion and oxygenation are significant factors in the healing process as well; inadequacies in either will likely result in a failure to heal or delay in the healing process. Chronic illnesses can often lead to impairments in perfusion and oxygenation.
Immunosuppressive conditions (cancer, diabetes) and treatments (chemotherapy, whether for cancer or autoimmune reasons, and corticosteroid therapy leading to immunosuppression) cause impairment of the initial inflammatory response required for healing to occur and therefore usually result in delayed wound healing.
Finally, neurologic conditions often result in refractory wounds as well. Spinal cord injury (SCI) patients are known to have delayed healing below the level of injury for many reasons: persistent inflammation, edema, and changes in perfusion and oxygenation.1 Additionally, SCI patients are at a high risk for pressure injury development given their impaired sensory perception, impaired mobility, and often altered weight-bearing status. SCI patients are often identified as at risk for pressure injuries according to the Braden Scale.
It is important to piece together all of the systemic factors impacting healing when looking at reasons that a wound is not improving within two to four weeks of evidenced-based topical therapy and a comprehensive plan of care. Additionally, it is always important to remember to treat the WHOLE patient, not just the HOLE in the patient—a common theme among many of my prior blogs.
In future blogs, we will be exploring and defining the remaining three common factors affecting tissue repair: extrinsic factors, iatrogenic factors, and adherence.
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