Standard, Appropriate, and Advanced Care andMedical-Legal Considerations: Part One—Diabetic Foot Ulcerations (A)

Introduction There are many variations on the definition and interpretation of the phrase standard of care. Definitions may vary depending on the training of the healthcare providers, including physicians, podiatrists, nurses, physical therapists, and medical assistants. Malpractice insurance companies, lawyers, and medical boards may interpret standard of care differently. Definitions may also be determined by the type of care administered by the majority of healthcare providers within a community. The legal and professional boards generally believe that standard of care is, “...based on the degree of care, skill, and learning expected of a reasonably prudent healthcare provider in the profession or class to which he or she belongs.”[1] While this definition reflects reasonable care, it does not necessarily include the administration of appropriate care. Appropriate care, although not currently defined in the literature, may be considered as the administration of care by a healthcare provider that addresses the specific needs of the patient and that may be reasonably expected based on the degree, skill, and experience of the profession or class to which the healthcare provider belongs. Appropriate care may not entail the same treatment as standard care. When providing appropriate care, individual consideration is given to each patient and his or her wound etiology. Advanced care, also not currently defined in the literature, may be considered the use of drugs, devices, or treatment regimens that may be experimental, newly approved, or above and beyond treatment modalities routinely used in the general community for a specific medical problem. Advanced care may sometimes be the only means of rapidly and effectively attaining wound closure. Universal standards of care are not available for the treatment of chronic ulcers. The American Diabetes Association provides guidelines for the treatment of the diabetic foot but intentionally does not clearly delineate treatment, ostensibly allowing for advances in this area.[2] There are also the American College of Foot and Ankle Surgeons (ACFAS) Guidelines and the American Pharmacuetical Association (APhA) guidelines.[3,4] Recommended guidelines for care of venous ulcers are provided in McGuckin’s Venous Ulcer Guideline.[5] These guidelines are for suggested care and may be considered a fair representation of expected treatment. In addition, the Clinical Practice Guideline for the Treatment of Pressure Ulcers is available from the Agency for Healthcare Research and Quality (AHRQ).[6] This is part one of a two-part series featured in this issue of WOUNDS. Part one focuses on guidelines for the treatment of diabetic ulcers. Part two (Ennis and Meneses), also included in this issue, focuses on treatment of venous ulcers. Extensive publications and guidelines for pressure ulcers may already be found in the medical literature. In this series, standard care versus appropriate care will be presented from a clinical perspective and in context of the specific etiology under review. Advanced treatment modalities, including growth factors and skin replacements, will be discussed and presented with respect to their roles in standard and appropriate care of diabetic foot ulcers. Diabetic Ulcer Overview There are at least 16 million people with diabetes in the United States,[7] and approximately 800,000 new cases are diagnosed each year.[8] Fifteen percent of all patients with diabetes may be expected to develop foot ulcers during their lifetimes.[9] Significant morbidity and mortality is associated with diabetic ulcers. Persons with diabetes have an increased risk of developing infections with subsequent complications secondary to impaired macrophage and cellular immune responses.[10,11] Nonhealing ulcers may become infected ulcers and are a major cause of lower-extremity amputation, which is 15 times more likely to occur in people with diabetes versus people without diabetes.[4] Approximately 67,000 amputations were performed each year between 1993 and 1995 among people with diabetes.[8] Once amputation occurs, approximately 50 percent of the people with amputations will develop ulceration with associated infection on the contralateral limb within 18 months of the amputation; fifty-eight percent have contralateral amputations three to five years subsequent to the first amputation.[9] The three-year mortality rate after the first amputation is between 20 and 50 percent.[9] Significant healthcare costs are associated with ulceration of the diabetic foot. Routine ulcer care, infections, hospitalizations, amputations, and diabetes-related care cost billions of dollars. In 1997, inpatient, outpatient, and outpatient pharmaceutical medical expenditures incurred by the diabetic population totaled 77.7 billion dollars.[12] The total direct and indirect cost of care related to diabetes was estimated to be 98 billion dollars.[12] A recent manuscript by Weiman, et al.,[13] reported costs for a nonoperable treatment of a single ulcer to be 7,000 to 8,000 dollars. Infected ulcers cost 17,000 to 18,000 dollars while amputations were approximately 45,000 dollars, excluding rehabilitation costs. Appropriate and advanced treatment may significantly reduce the high morbidity, mortality, and cost of care associated with diabetic foot ulcers by expediting wound closure. The longer an ulcer remains open, the greater the chance of colonization, infection, and amputation. Timely closure of an ulcer may be expected to reduce the probability of secondary complications. Patient Assessment A thorough history and physical examination is the first step necessary to determine the patient and ulcer status, establish a baseline for treatment, develop a treatment plan, determine a patient’s risk status, and provide a prognosis for wound closure. Historical information should include diabetes control, current and past complications and treatments, and comorbidities. Physical examination should include information on vascular, neurological, and musculoskeletal status. Neurological status. A simple neurological examination performed with a 5.07 monofilament provides immediate information on the degree of patient neuropathy. Semmes-Weinstein monofilaments are inexpensive devices recommended for neurosensory testing.[14] The 5.07 monofilament is considered the single most practical measurement of ulcer risk assessment.[14] Clinical recommendations for treatment of people with diabetes suggest that all patients should be assessed annually with the Semmes-Weinstein monofilament.[15,16] Vibratory perception threshold (VPT) is tested with a biothesiometer or with a 128-Hz tuning fork.[12,16,17] Inability to perceive vibration from the tuning fork correlates with loss of protective sensation. Armstrong, et al.,[17] found that insensitivity to Semmes-Weinstein 5.07 monofilament at four or more sites combined with a VPT using a biothesiometer at 25V had a sensitivity of 100 percent and specificity of 76.5 percent in screening for risk of diabetic foot ulceration in diabetic patients. The greater the degree of neuropathy, the greater is the risk of developing a diabetic foot. Neuropathic patients have reduced awareness of trauma, infection, and complications, which may occur on the foot ulcer. Sensory, motor, and autonomic neuropathy represents the greatest risk for ulcer development in diabetic patients.[18] Motor neuropathy affects the function of the intrinsic and extrinsic musculature of the foot.[19,20] Claw toes, hammer toes, and shifting of the weight from the toes to the metatarsal heads may lead to increased pressure over boney prominences, excessive and abnormal pressures, and subsequent ulceration.[20] Patients must be educated on the risks of ulcer formation and how to decrease the risk of ulcer development through offloading devices. Autonomic neuropathy is reflected by decreased sweating, loss of skin temperature regulation, and autosympathectomy. Anhydrosis results in xerotic skin and predisposes skin to fissures, cracks, and callus formation.[10] Once neuropathy has been established, related education becomes a component of appropriate care. The patient must be made aware of the increased need for lower-extremity pressure reduction, offloading, and routine examinations. Neurosensory testing is an essential component of appropriate care yet is not standard care in the majority of treatment settings. Neuropathy will not be detected unless the clinician performs the necessary tests. Detecting and interpreting the results of neurosensory testing will help establish the guidelines for appropriate treatment. Vascular status. The vascular examination, particularly the noninvasive vascular exam, establishes the degree of vascular and tissue perfusion. Patients with severe arterial disease will have difficulty with wound closure and are at high risk for amputation secondary to inadequate oxygenation and perfusion of tissue. Peripheral arterial disease may contribute to complications and death.[21] Atherosclerotic disease in a diabetic patient is the same as in the nondiabetic patient; however, the vessels between the knee and ankle are involved, with sparing of the pedal vessels in the majority of cases. There is no evidence of microvascular occlusion in the diabetic patient, although there is good evidence of microvascular dysfunction, which can affect local flow. Although distal bypass may no longer still be the standard of care in the diabetic patient, it is certainly appropriate.[22] While most ulcers are of neuropathic or mixed etiology, ischemic ulcers occur in approximately 10 percent of diabetic patients.[8] Vascular testing of new and high-risk patients may not be viewed as part of standard care, yet it is appropriate care, as results will guide the type and degree of medical intervention. Manual pulse examination is part of a standard examination; however, it does not adequately determine the patient’s vascular status. Doppler-derived lower-extremity arterial pressures or Doppler or pulse volume waveforms assist with determining foot pulses while eliminating the risk of feeling one’s own pulse while palpating the foot. Ankle-brachial index (ABI) measurements are useful but may provide falsely elevated rates due to noncompressible arteries, which result from medial arterial calcification.20 While transcutaneous oxygen (TcpO2) measurement is a useful tool for measuring local tissue oxygenation, the extensive equipment necessary for these measurements may not be available to most clinicians. Duplex imaging, laser Doppler, and skin perfusion measurements all help determine levels of flow and oxygenation of affected tissue. Toe pressures can also be considered a standard noninvasive measure to determine adequate perfusion into the digits. Patients with severe vessel occlusion may not be candidates for sharp/surgical wound debridement and, when not surgical candidates for revascularization, may be at a high risk for limb loss. Debriding nonviable tissue in a patient without the potential to heal may result in a larger wound. Through appropriate testing and determination of vascular status, treatment expectations and wound closure potential may be established and treatment prognosis and potential clearly explained to the patient. A patient that understands his or her own medical status and risks, including risks associated with morbidity and mortality, is less likely to take legal action in the face of a complication secondary to treatment. Musculoskeletal exam. The musculoskeletal exam and associated radiographs may identify deformities resulting in focal points of increased pressure. Repetitive trauma to these sites, as well as sustained pressure, shear, and friction, may contribute to ulcer development. Appropriate intervention may include palliative care, surgery, or prophylactic measures. Appropriate care entails addressing the above issues to reduce the incidence of ulcer development and to assist with wound closure. Patient education and compliance become integral parts of addressing musculoskeletal deformities through offloading devices and conservative care. Severe deformities, prescribed treatment, and noncompliance must be carefully and legibly documented in the patient’s records. A comprehensive assessment of the patient and the ulcer assists with the determination of risk factors. The number and types of risk factors are correlated with the risk of ulceration. Lavery, et al., defined risk on the basis of loss versus no protective sensation, presence of deformity, and history of amputation.[23] Simeone and Veves have also been published on these risks for diabetic ulceration.[24] Additional factors, including age, obesity, duration of diabetes, and glycosylated hemoglobin (HbA1c), are associated with an increased incidence of ulcers.[25] High-risk patients without ulceration should be examined every three months,[26] while those with open wounds not requiring hospitalization should be seen at least once a week. Even people with diabetes at low risk for ulceration and amputation should have their feet examined on an annual basis, while moderate risk patients may be seen twice a year. The latter examination schedule would be considered appropriate care. Appropriate care extends beyond a brief wound examination to include all the above factors as well as patient education about foot care and individual risk for limb loss. The patient’s knowledge of his or her medical status, his or her ability to care for the wound, and his or her compliance will directly affect treatment results. Elderly and disabled individuals may require home or special care. Documentation of the patient’s compliance and level of understanding is important from a treatment and medical-legal perspective. Standard care does not include these assessments, while appropriate care encompasses all aspects of the global assessment. Ulcer Assessment and Documentation Complete ulcer examination and documentation of findings should be a part of every visit for patients with diabetic foot ulcers. Physical findings need to include information on location, shape, condition of wound bed, signs of infection, deterioration, and other characteristics listed on the sample forms in Figures 1A and B, 2A and B, and 3. Physical findings should be recorded at baseline and all subsequent visits and correlated to the extent of wound closure. Differential diagnoses should be established after physical findings have been noted. Assumptions should not be made that an ulcer is a diabetic foot ulcer without first ruling out other etiologies. In diabetic patients, these may include but are not limited to venous ulcers, ischemic ulcers, vasculitic ulcers, and malignancies. Ulcer classification must be consistent and reproducible. Either the Wagner[27] or the University of Texas system[28] may be used. Regardless of which system is chosen, the key factors associated with poor outcome, depth, presence of infection, and presence of ischemia should be considered. Once an ulcer has been thoroughly examined and the findings documented, a treatment plan may then be established. Patients with problems and requiring care determined to be out of the scope of the clinician treating the wound should be referred to the appropriate specialist. Ulcer Treatment Guidelines for general care of the diabetic foot ulcer were established by the American Diabetes Association (ADA). The ADA 1999 Clinical Practice Recommendations[2] list the following recommendations for foot care in patients with diabetes mellitus: Prompt and proper care of diabetic foot ulcers is essential. The healthcare professional should 1) establish the ulcer’s etiology; 2) measure its size; 3) establish its depth and determine the involvement of deep structures; 4) examine it for purulent exudate, necrosis, sinus tracts, and odor; 5) assess the surrounding tissue for signs of edema, cellulitis, abscess, and fluctuation; 6) exclude systemic infection; and 7) perform a vascular evaluation. The ability to gently probe through the ulcer to bone has been shown to be highly predictive of osteomyelitis.[29] The above guidelines recommend components of care but neither delineate what is appropriate for each patient nor describe advanced modalities, which may expedite closure. A more in-depth understanding of each component of treatment will assist in providing appropriate and advanced care. Ulcer Etiology Establishing the ulcer’s etiology is necessary if one is to treat appropriately. As previously mentioned, vascular status must be examined to determine the degree of flow. When severe occlusion is present, surgical intervention may be recommended. Vasodilators have not been proven to assist with the healing of diabetic foot ulcers. Vasoconstricting drugs need to be avoided in the diabetic patient.[2] Sharp debridement is contraindicated in the presence of severe occlusion. If the patient has a dry intact eschar, do not debride, but if it is wet and loose, the loose tissue should be removed gently without causing damage to viable tissue. Diabetic patients may also present with lower-extremity ulcers of venous, vasculitic, or other etiologies. The underlying pathophysiology needs to be addressed even when it is not related to diabetes. Misdiagnosis may result in a higher incidence of morbidity and mortality. Ulcer Measurements and Examination Complete ulcer measurements along with other qualitative and quantitative assessments need to be included in the patient’s record at the initial and all subsequent visits. Wound measurements and data assist with determining wound progress and effects of treatment. Wound depth may affect the choice of treatment. When deep structures are involved, particularly in the case of bone, osteomyelitis must be ruled out. The presence of purulent exudate is an indicator of clinical infection and requires appropriate antibiotic therapy. Purulent drainage may be mimicked by residue from dressings including, but not limited to, alginates, hydrocolloids, and collagens. Once a dressing has been removed and the wound is cleaned, purulence should not be present. Odor alone may be the result of contamination or colonization and is not necessarily an indicator of clinical infection.[30] Assessment of periwound area is important. The presence of erythema, maceration, and tissue breakdown are indicators of additional complications, which may interfere with wound closure. Infection must be recognized and treated without delay. Limb-threatening bacterial infections of diabetic foot ulcers are usually polymicrobial.[2,31] The potential for rapid deterioration in infected diabetic ulcers warrants the immediate use of a broad-spectrum antibiotic, which later can be modified based on culture results. Deep specimens and biopsies provide the most accurate results, although white blood cell (WBC)-labeled scans may also be used to assist with diagnosis.[32] Bone exposure closely correlates with ostemyelitis.[29,33] A standard radiological exam may assist with the diagnosis but is not as reliable as magnetic resonance imaging (MRI). Standard radiographic films have poor sensitivity and specificity for early osteomyelitis. However, standard x-rays should be taken for every new patient and used as a baseline comparison for x-rays taken later in a patient’s treatment regimen. The x-rays can be used to rule out boney abnormalities, gas, and foreign bodies. Changes in subsequent radiographs compared with baseline radiographs may provide useful data on progression of osteomyelitis. Debridement Debridement may be considered one of the most important aspects of diabetic foot ulcer care, along with offloading and infection control. ADA guidelines recommend debridement of abscessed tissue along with incision and drainage.[2] Debridement is the removal of necrotic tissue to decrease the risk of infection and to promote wound closure. Debridement should remove all necrotic tissue, callus, and foreign bodies down to the level of viable bleeding tissue. Wounds should be thoroughly flushed with sterile saline or a noncytotoxic cleanser following debridement. Hydrotherapy is not recommended for diabetic patients.[2,29,34,35] Debridement is essential for the removal of nonviable cells and for healing.[36] Periwound callus must also be removed, as it may contribute to periwound pressure and incomplete wound contraction. Ulcers may also be obscured by the presence of callus. Vascular status must always be determined prior to sharp surgical debridement. This may be accomplished through techniques described earlier in this manuscript. Determining local perfusion is of particular importance when debriding ulcers on the distal aspect of the foot. Debridement is contraindicated in patients with significant vascular compromise, without healing potential, or when they are placed at greater risk. Debridement of dry eschar in the compromised patient may not be necessary.[37] Special considerations include inadequate blood flow, immunosuppressive therapies, poor nutrition, inadequate diabetes control, and high levels of anticoagulants. Consideration of risk versus benefit must be made in cases where deeper structures, such as tendon, bone, or capsule, may be exposed as a result of debridement. Clean, granulating wounds should not be debrided. Enzymatic debridement may be considered when sharp surgical intervention is not an option. Enzymatic debridement may be slow and ineffective where thick dry eschar is present. Enzymes will not debride the periwound callus. Autolytic debridement through accumulation of exudate under occlusion is not recommended in diabetic patients as the pooling of fluid promotes bacterial proliferation, which may place the diabetic patient at increased risk for infection. In this same population, one may also consider larval (maggot) therapy, although this is not a popular method in the US.[38] In the absence of diabetes, an individual cellular immune response results in prolonged macrophage activity in a moist environment.[39] Increased moisture may promote autolysis without increasing the risk of infection. In persons with diabetes and other individuals with a compromised cellular immune response, pooling of fluid may promote colonization leading to infection. Offloading Reduction of pressure, or offloading, is another essential aspect of diabetic wound care. Foot pressures, shock, and shear can be reduced with appropriately fitted shoes, insoles, and socks.[10,40] Total nonweight bearing using a wheelchair or crutches is the most effective method of relieving pressure although most patients have difficulty complying with these modalities. Total contact casts (TCCs) and removal casts are effective in significantly reducing pressure but may cause additional problems when inappropriately applied. TCCs are used for offloading the plantar aspect of the foot. Published studies suggest TCCs heal greater than 72 percent of all patients treated with them.[41] Clinical skill is required for application. Patient compliance is necessary to minimize complications. Inappropriate application may result in a new ulceration. Postural instability may be exacerbated. Contraindications include acute infection ischemia, deep ulcers, and draining wounds.[42] Additional contraindications include ataxic patients and those who are noncompliant, blind, morbidly obese, or have severe peripheral arterial disease.[43] In general, wounds on the posterior heel should not be treated with TCCs. Pragmatically, removable cast walkers may be preferable to TCCs, as they do not have the same inherent disadvantages. Pressure reduction has been shown to be similar to TCCs with certain types of these devices.[23] Removable walking casts facilitate daily wound inspection and wound care. Infection can be readily detected and complications addressed. Unfortunately, while these devices may seem to be equivalent to TCCs, the fact that they are removable often leads to lapses in adherence to care. Also, patients should not drive automobiles while wearing casts or any offloading device. Therapeutic footwear is designed primarily for the prevention of ulcer occurrence. A large variety of shoes and ambulatory devices, including but not limited to half shoes and crow walkers, are available for different problems.[40] Shoes should be selected based on the patient’s individual needs. When using shoes on patients with diabetic foot ulcers, extra space must be allotted for bulky dressings, which may increase local pressure when in a tightly fitting shoe. Regular assessment of shoes in patients with and without ulcers should be performed to the shoes to ensure the shoes are still appropriate for the patient’s needs. The Medicare-supported Therapeutic Shoe Bill pays for special footwear and insoles. The benefit provides for one pair of custom-molded shoes plus two additional pairs of insoles or one pair of over-the-counter extra-depth shoes plus three pairs of insoles per year. A physician treating the patient must document previous amputation, history of ulcers, pre-ulcer callus, foot deformity, or poor peripheral circulation.[44] Standard recommendations in the majority of outpatient settings usually consist of a prescription for a post-surgical shoe or over-the-counter athletic shoes. The latter devices are not appropriate for the diabetic foot, as they are not designed to reduce pressure or prevent trauma in the abnormal and insensate foot. Custom-molded shoes and/or inserts are appropriately prescribed for the foot requiring reduction in pressure and repetitive trauma. It is beyond the scope of this paper to discuss surgical options and approaches for the treatment and prevention of diabetic lower-extremity ulcers. However, when conservative or nonoperative therapy has failed or is not an option, surgical options need to be considered. Infection Control The single most frequent cause of amputation in the diabetic foot is the diabetic wound, which becomes the portal of bacterial entry, colonization, and subsequent infection.[18,31] While it is beyond the scope of this paper to discuss management of infection, various measures may be taken to reduce the risks and complications of colonization. Diabetic ulcers are at high risk of infection secondary to impaired leukocyte chemotaxis and phagocytosis. High glucose levels and poor tissue perfusion may compound this condition. Decreased ability to fight off infection combined with tissue hypoxia creates an ideal environment for a necrotizing infection.[10,45] Limb-threatening diabetic infections are usually polymicrobial involving multiple aerobic and anaerobic infections. Staphylococcus aureus, beta-hemolytic streptococcus, Enterobacteriaceae, Bacteroides fragilis, Peptococcus, and Peptostreptococcus may be cultured from diabetic ulcers. Malodorous wounds are likely to harbor aerobic and anaerobic organisms.[31] Choice of antimicrobials in the treatment of a limb-threatening diabetic foot ulcer infection should include those with activity against Gram-positive and Gram-negative organisms and provide aerobic and anaerobic coverage. The patient’s overall wound and medical status as well as the patient’s medical history determine the choice of oral versus intravenous antibiotics and the need for hospitalization. Clinicians may not have the luxury of awaiting culture or biopsy results prior to determining antibiotic choice. Treatment may be changed when dictated by the culture result or when the patient is not responding to treatment. Cultures are most reliable when a deep tissue specimen is obtained.[32] All organisms recovered from deep tissue cultures should be treated as pathogens unless there is evidence to support that the culture was contaminated from another source. Swab cultures usually grow out numerous surface contaminants and may not provide information on the pathogen(s) causing the deep tissue infection. The rapid deterioration of an infected wound in the diabetic patient necessitates immediate action by a clinician to prevent amputation and other complications. Topical antibiotics and antimicrobials are not indicated for the treatment of a deep tissue or bone infection. Topical agents may reduce colonization in the wound, thereby reducing the risk of infection. Topical antimicrobials have neither been proven to eradicate an infection nor to be effective in the treatment of an infection. The primary line of therapy for infection is the use of oral or systemic antibiotics. It is the responsibility of the clinician to differentiate between contamination (the presence of organisms in a wound), colonization (the multiplication of organisms), and infection (the presence of greater than 1 x 105 organisms per gram of tissue).[45] Diagnosis of an infection should be based on clinical findings. Cultures are meant to identify organisms and to assist in treatment of an infection rather than be used to diagnose infection. Antibiotics are known to be used indiscriminately and without need resulting in an increased probability of developing resistance.[46,47] The high morbidity and mortality associated with infected diabetic ulcers suggest that the prescription antibiotics may be more appropriate when clinical signs of infection are suspected in a diabetic ulcer than in wounds of other etiologies, with the exception of immunocompromised patients. Bone detected by probing a pedal ulcer has a sensitivity of 66 percent for osteomyelitis and a specificity of 85 percent.[29] Determining the presence of osteomyelitis may prove difficult when Charcot disease is co-existent.[32] While standard radiographs may be of assistance in diagnosing osteomyelitis, MRI is considered the more sensitive and specific pathologic confirmation of osteomyelitis. Serial radiographs compared with baseline radiographs may be of significant value in determining progressive bone changes resulting from osteomyelitis. Clinicians are advised to use clinical findings and judgment in conjunction with all available test results, including but not limited to radiographs, MRI, and scans, prior to determining the presence of osteomyelitis. Appropriate care may include surgical intervention, bone debridement, infectious disease consultation, extended antibiotic therapy, and hospitalization. In patients with osteomyelitis that has been present for extended periods of time without complications, recurrent ulcerations, or significant progression, the clinician may decide to defer aggressive intervention. [This article is continued in "Standard, Appropriate, and Advanced Care and Medical-Legal Considerations: Part One: Diabetic Foot Ulcerations (B)]