best practice guidelines: wound management in diabetic foot ulcers

INTERNATIONAL BEST PRACTICE

BEST PRACTICE GUIDELINES: WOUND MANAGEMENT IN DIABETIC FOOT ULCERS

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BEST PRACTICE GUIDELINES FOR SKIN AND WOUND CARE IN EPIDERMOLYSIS BULLOSA

FOREWORD

Supported by an educational grant from B Braun

The views presented in this document are the work of the authors and do not necessarily reflect the opinions of B Braun.

Published by Wounds International A division of Schofield Healthcare Media Limited Enterprise House 1–2 Hatfields London SE1 9PG, UK www.woundsinternational.com

To cite this document. International Best Practice Guidelines: Wound Management in Diabetic Foot Ulcers. Wounds International, 2013. Available from: www. woundsinternational.com

This document focuses on wound management best practice for diabetic foot ulcers (DFUs). It aims to offer specialists and non-specialists everywhere a practical, relevant clinical guide to appropriate decision making and effective wound healing in people presenting with a DFU. In recognition of the gap in the literature in the field of wound management, this document concentrates on the importance of wound assessment, debridement and cleansing, recognition and treatment of infection and appropriate dressing selection to achieve optimal healing for patients. However, it acknowledges that healing of the ulcer is only one aspect of management and the role of diabetic control, offloading strategies and an integrated wound care approach to DFU management (which are all covered extensively elsewhere) are also addressed. Prevention of DFUs is not discussed in this document. The scope of the many local and international guidelines on managing DFUs is limited by the lack of high-quality research. This document aims to go further than existing guidance by drawing, in addition, from the wide-ranging experience of an extensive international panel of expert practitioners. However, it is not intended to represent a consensus, but rather a best practice guide that can be tailored to the individual needs and limitations of different healthcare systems and to suit regional practice.

EXPERT WORKING GROUP Development group Paul Chadwick, Principal Podiatrist, Salford Royal Foundation Trust, UK Michael Edmonds, Professor of Diabetes and Endocrinology, Diabetic Foot Clinic, King's College Hospital, London, UK Joanne McCardle, Advanced Clinical and Research Diabetes Podiatrist, NHS Lothian University Hospital, Edinburgh, UK David Armstrong, Professor of Surgery and Director, Southern Arizona Limb Salvage Alliance (SALSA), University of Arizona College of Medicine, Arizona, USA Review group Jan Apelqvist, Senior Consultant, Department of Endocrinology, Skåne University Hospital, Malmo, Sweden Mariam Botros, Director, Diabetic Foot Canada, Canadian Wound Care Association and Clinical Coordinator, Women's College Wound Healing Clinic, Toronto, Canada Giacomo Clerici, Chief Diabetic Foot Clinic, IRCC Casa di Cura Multimedica, Milan, Italy Jill Cundell, Lecturer/Practitioner, University of Ulster, Belfast Health and Social Care Trust, Northern Ireland Solange Ehrler, Functional Rehabilitation Department, IUR Clémenceau (Institut Universitaire de Réadaptation Clémenceau), Strasbourg, France Michael Hummel, MD, Diabetes Center Rosenheim & Institute of Diabetes Research, Helmholtz Zentrum München, Germany Benjamin A Lipsky, Emeritus Professor of Medicine, University of Washington, USA; Visiting Professor, Infectious Diseases, University of Geneva, Switzerland; Teaching Associate, University of Oxford and Deputy Director, Graduate Entry Course, University of Oxford Medical School, UK José Luis Lázaro Martinez, Full Time Professor, Diabetic Foot Unit, Complutense University, Madrid, Spain Rosalyn Thomas, Deputy Head of Podiatry, Abertawe Bro Morgannwg University Health Board, Swansea, Wales Susan Tulley, Senior Podiatrist, Mafraq Hospital, Abu Dhabi, United Arab Emirates

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BEST PRACTICE GUIDELINES: WOUND MANAGEMENT DIABETIC FOOTBULLOSA ULCERS BEST PRACTICE GUIDELINES FOR SKIN AND WOUND CARE ININ EPIDERMOLYSIS

INTRODUCTION

Introduction DFUs are complex, chronic wounds, which have a major long-term impact on the morbidity, mortality and quality of patients’ lives1,2. Individuals who develop a DFU are at greater risk of premature death, myocardial infarction and fatal stroke than those without a history of DFU3. Unlike other chronic wounds, the development and progression of a DFU is often complicated by wide-ranging diabetic changes, such as neuropathy and vascular disease. These, along with the altered neutrophil function, diminished tissue perfusion and defective protein synthesis that frequently accompany diabetes, present practitioners with specific and unique management challenges1. DFUs are relatively common — in the UK, 5–7% of people with diabetes currently have or have had a DFU4,5. Furthermore, around 25% of people with diabetes will develop a DFU during their lifetime6. Globally, around 370 million people have diabetes and this number is increasing in every country7. Diabetes UK estimates that by 2030 some 552 million people worldwide will have diabetes8. DFUs have a major economic impact. A US study in 1999 estimated the average outpatient cost of treating one DFU episode as $28,000 USD over a two–year period9. Average inpatient costs for lower limb complications in 1997 were reported as $16,580 USD for DFUs, $25,241 USD for toe or toe plus other distal amputations and $31,436 USD for major amputations10,11.

such as the effect on physical, psychological and social wellbeing and the fact that many patients are unable to work long term as a result of their wounds6. A DFU is a pivotal event in the life of a person with diabetes and a marker of serious disease and comorbidities. Without early and optimal intervention, the wound can rapidly deteriorate, leading to amputation of the affected limb5,13. It has been estimated that every 20 seconds a lower limb is amputated due to complications of diabetes14. In Europe, the annual amputation rate for people with diabetes has been cited as 0.50.8%1,15, and in the US it has been reported that around 85% of lower-extremity amputations due to diabetes begin with foot ulceration16,17. Mortality following amputation increases with level of amputation18 and ranges from 50–68% at five years, which is comparable or worse than for most malignancies13,19 (Figure 1). The statistics need not make for such grim reading. With appropriate and careful management it is possible to delay or avoid most serious complications of DFUs1. FIGURE 1: Relative five-year mortality (%) (adapted from19)

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In England, foot complications account for 20% of the total National Health Service spend on diabetes care, which equates to around £650 million per year (or £1 in every £150)5. Of course, these figures do not take account of the indirect costs to patients,

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The EURODIALE study examined total direct and indirect costs for one year across several European countries. Average total costs based on 821 patients were approximately 10,000 euros, with hospitalisation representing the highest direct cost. Based on prevalence data for Europe, they estimated that costs associated with treatment of DFUs may be as high as 10 billion euros per year12.


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INTRODUCTION

It has been suggested that up to 85% of amputations can be avoided when an effective care plan is adopted20. Unfortunately, insufficient training, suboptimal assessment and treatment methods, failure to refer patients appropriately and poor access to specialist footcare teams hinder the prospects of achieving optimal outcomes21,22. Successful diagnosis and treatment of patients with DFUs involves a holistic approach that includes: Q Optimal diabetes control Q Effective local wound care Q Infection control Q Pressure relieving strategies Q Restoring pulsatile blood flow. Many studies have shown that planned intervention aimed at healing of DFUs is most effective in the context of a multidisciplinary team with the patient at the centre of this care. One of the key tenets underpinning this document is that infection is a major threat to DFUs — much more so than to wounds

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of other aetiologies not subject to diabetic changes. A European-wide study found that 58% of patients attending a foot clinic with a new ulcer had a clinically infected wound23. Similarly a single-centre US study found that about 56% of DFUs were clinically infected24. This study also showed the risk of hospitalisation and lower-extremity amputation to be 56–155 times greater for diabetes patients with a foot infection than those without24. Recognising the importance of starting treatment early may allow practitioners to prevent progression to severe and limb-threatening infection and potentially halt the inevitable pathway to amputation25. This document offers a global wound care plan for practitioners (page 20), which includes a series of steps for preventing complications through active management — namely prompt and appropriate treatment of infection, referral to a vascular specialist to manage ischaemia and optimal wound care. This should be combined with appropriate patient education and an integrated approach to care.


AETIOLOGY OF DFUs

Aetiology of DFUs The underlying cause(s) of DFUs will have a significant bearing on the clinical management and must be determined before a care plan is put into place In most patients, peripheral neuropathy and peripheral arterial disease (PAD) (or both) play a central role and DFUs are therefore commonly classified as (Table 1)26: Q Neuropathic Q Ischaemic Q Neuroischaemic (Figures 2–4). Neuroischaemia is the combined effect of diabetic neuropathy and ischaemia, whereby macrovascular disease and, in some instances, microvascular dysfunction impair perfusion in a diabetic foot26,27.

PERIPHERAL NEUROPATHY Peripheral neuropathy may predispose the foot to ulceration through its effects on the sensory, motor and autonomic nerves: Q The loss of protective sensation experienced by patients with sensory neuropathy renders them vulnerable to physical, chemical and thermal trauma Q Motor neuropathy can cause foot deformities (such as hammer toes and claw foot), which may result in abnormal pressures over bony prominences Q Autonomic neuropathy is typically associated with dry skin, which can result in fissures, cracking and callus. Another feature is bounding pulses, which is often misinterpreted as indicating a good circulation28. Loss of protective sensation is a major component of nearly all DFUs29,30. It is associated with a seven–fold increase in risk of ulceration6. Patients with a loss of sensation will have decreased awareness of pain and other symptoms of ulceration and infection31.

is increasing and it is reported to be a contributory factor in the development of DFUs in up to 50% of patients14,28,33. It is important to remember that even in the absence of a poor arterial supply, microangiopathy (small vessel dysfunction) contributes to poor ulcer healing in neuroischaemic DFUs34. Decreased perfusion in the diabetic foot is a complex scenario and is characterised by various factors relating to microvascular dysfunction in addition to PAD34. DFUs usually result from two or more risk factors occurring together. Intrinsic elements such as neuropathy, PAD and foot deformity (resulting, for example, from neuropathic structural changes), accompanied by an external trauma such as poorly fitting footwear or an injury to the foot can, over time, lead to a DFU7.

FIGURE 3: Ischaemic DFU

FIGURE 4: Neuroischaemic DFU

TABLE 1: Typical features of DFUs according to aetiology Feature

Neuropathic

Ischaemic

Neuroischaemic

Sensation

Sensory loss

Painful

Degree of sensory loss

Callus/necrosis

Callus present and often thick

Necrosis common

Minimal callus Prone to necrosis

Wound bed

Pink and granulating, surrounded by callus

Pale and sloughy with poor granulation

Poor granulation

Foot temperature and pulses

Warm with bounding pulses

Cool with absent pulses

Cool with absent pulses

Other

Dry skin and fissuring

Delayed healing

High risk of infection

Typical location

Weight-bearing areas of the foot, such as metatarsal heads, the heel and over the dorsum of clawed toes

Tips of toes, nail edges and between the toes and lateral borders of the foot

Margins of the foot and toes

Prevalence (based on35)

35%

15%

50%

PERIPHERAL ARTERIAL DISEASE People with diabetes are twice as likely to have PAD as those without diabetes32. It is also a key risk factor for lower extremity amputation30. The proportion of patients with an ischaemic component to their DFU

FIGURE 2: Neuropathic DFU


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ASSESSING DFUs

Assessing DFUs Patients with a DFU need to be assessed holistically and intrinsic and extrinsic factors considered For the non-specialist practitioner, the key skill required is knowing when and how to refer a patient with a DFU to the multidisciplinary footcare team (MDFT; see page 19). Patients with a DFU should be assessed by the team within one working day of presentation — or sooner in the presence of severe infection22,36,37. In many places, however, MDFTs do not exist and practitioners instead work as individuals. In these situations, the patient’s prognosis often depends on a particular practitioner’s knowledge and interest in the diabetic foot. Patients with a DFU need to be assessed holistically to identify intrinsic and extrinsic factors. This should encompass a full patient history including medication, comorbidities and diabetes status38. It should also take into consideration the history of the wound, previous DFUs or amputations and any symptoms suggestive of neuropathy or PAD28.

EXAMINATION OF THE ULCER A physical examination should determine: Q Is the wound predominantly neuropathic, ischaemic or neuroischaemic? Q If ischaemic, is there critical limb ischaemia? Q Are there any musculoskeletal deformities? Q What is the size/depth/location of the wound? Q What is the colour/status of the wound bed? — Black (necrosis) — Yellow, red, pink Q Is there any exposed bone? Q Is there any necrosis or gangrene? Q Is the wound infected? If so, are there systemic signs and symptoms of infection (such as fevers, chills, rigors, metabolic instability and confusion)? Q Is there any malodour? Q Is there local pain? Q Is there any exudate? What is the level of production (high, moderate, low, none), colour and consistency of exudate, and is it purulent? Q What is the status of the wound edge (callus, maceration, erythema, oedema, undermining)? 4 3

Documenting ulcer characteristics Recording the size, depth, appearance and location of the DFU will help to establish a baseline for treatment, develop a treatment plan and monitor any response to interventions. It is important also to assess the area around the wound: erythema and maceration indicate additional complications that may hinder wound healing38. Digitally photographing DFUs at the first consultation and periodically thereafter to document progress is helpful39. This is particularly useful for ensuring consistency of care among healthcare practitioners, facilitating telehealth in remote areas and illustrating improvement to the patient.

TESTING FOR LOSS OF SENSATION Two simple and effective tests for peripheral neuropathy are commonly used: Q 10g (Semmes-Weinstein) monofilament Q Standard 128Hz tuning fork. The 10g monofilament is the most frequently used screening tool to determine the presence of neuropathy in patients with diabetes28. It should be applied at various sites along the plantar aspect of the foot. Guidelines vary in the number of sites advocated, but the international consensus is to test at three sites (see Figure 5)7. A positive result is the inability to feel the monofilament when it is pressed against the foot with enough force to bend it40. Neuropathy is also demonstrated by an inability to sense vibration from a standard tuning fork. Other tests are available, such as the biothesiometer and neurothesiometer, which are more complex handheld devices for assessing the perception of vibration. Do not test for neuropathy in areas of callus as this can mask feeling from any of the neuropathy testing devices and may give a false-positive result. Be aware that patients with small nerve fibre damage and intact sensory nerves may have


ASSESSING DFUs

FIGURE 5: Procedure for carrying out the monofilament test (adapted from7) The International Working Group on the Diabetic Foot (IWGDF) recommends the following procedure for carrying out the monofilament test. Q The sensory examination should be carried out in a quiet and relaxed setting Q The patient should close their eyes so as not to see whether or where the examiner

applies the monofilament Q The patient should sit supine with both feet level Q First apply the monofilament on the patient’s hands or on the inside of the arm so

they know what to expect Q Apply the monofilament perpendicular to the skin surface with sufficient force to

bend or buckle the monofilament Q Ask the patient:

— Whether they feel the pressure applied (yes/no) — Where they feel the pressure (left foot/right foot) Q Apply the monofilament along the perimeter of (not on) the ulcer site Q Do not allow the monofilament to slide across the skin or make repetitive contact at the test site Q The total duration of the approach (skin contact and removal of the monofilament) should be around 2 seconds Q Apply the monofilament to each site three times, including at least one additional ‘mock’ application in which no filament is applied Q Encourage the patient during testing by giving positive feedback — Protective sensation is present at each site if the patient correctly answers two out of three applications — Protective sensation is absent with two out of three incorrect answers Note: The monofilament should not be used on more than 10 patients without a recovery period of 24 hours

a painful neuropathy. They may describe sharp, stabbing, burning, shooting or electric shock type pain, which may be worse at night and can disrupt sleep41. The absence of coldwarm discrimination may help to identify patients with small nerve fibre damage.

TESTING FOR VASCULAR STATUS Palpation of peripheral pulses should be a routine component of the physical examination and include assessment of the femoral, popliteal and pedal (dorsalis pedis and posterior tibial) pulses. Assessment of pulses is a learned skill and has a high degree of inter-observer variability, with high falsepositive and false-negative rates. The dorsalis pedis pulse is reported to be absent in 8.1% of healthy individuals, and the posterior tibial pulse is absent in 2.0%. Nevertheless, the absence of both pedal pulses, when assessed by an experienced clinician, strongly suggests the presence of pedal vascular disease42. If

Using a monofilament to test for neuropathy

there is any doubt regarding diagnosis of PAD, it is important to refer to a specialist for a full vascular assessment. Where available, Doppler ultrasound, anklebrachial pressure index (ABPI) and Doppler waveform may be used as adjuncts to the clinical findings when carried out by a competent practitioner. Toe pressures, and in some instances, transcutaneous oxygen measurement (where equipment is available), may be useful for measuring local tissue perfusion. An ischaemic foot may appear pink and relatively warm even with impaired perfusion due to arteriovenous shunting. Delayed discolouration (rubor) or venous refilling greater than five seconds on dependency may indicate poor arterial perfusion43.

COMMON TERMS EXPLAINED Critical limb ischaemia: this is a chronic manifestation of PAD where the arteries of the lower extremities are severely blocked. This results in ischaemic pain in the feet or toes even at rest. Complications of poor circulation include skin ulcers or gangrene. If left untreated it will result in amputation of the affected limb. Acute limb ischaemia: this occurs when there is a sudden lack of blood flow to a limb and is due to either an embolism or thrombosis. Without surgical revascularisation, complete acute ischaemia leads to extensive tissue necrosis within six hours.

Other signs suggestive of ischaemia include40: Q Claudication: pain in the leg muscles and


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ASSESSING DFUs

Q

usually exercise-induced (although this is often absent in people with diabetes) A temperature difference between the feet.

If you suspect severe ischaemia in a patient with a DFU you should refer as quickly as possible to a MDFT with access to a vascular surgeon. If the patient has critical limb ischaemia this should be done urgently. A patient with acute limb ischaemia characterised by the six ‘Ps’ (pulselessness, pain, pallor [mottled colouration], perishing cold, paraesthesia and paralysis) poses a clinical emergency and may be at great risk if not managed in a timely and effective way44.

IDENTIFYING INFECTION Recognising infection in patients with DFUs can be challenging, but it is one of the most important steps in the assessment. It is at this crucial early stage that practitioners have the potential to curb what is often progression from simple (mild) infection to a more severe problem, with necrosis, gangrene and often amputation45. Around 56% of DFUs become infected and overall about 20% of patients with an infected foot wound will undergo a lower extremity amputation30. Risk factors for infection Practitioners should be aware of the factors that increase the likelihood of infection46: TABLE 2: Classification and severity of diabetic foot infections (adapted from46) Clinical criteria

Grade/severity

No clinical signs of infection

Grade 1/uninfected

Superficial tissue lesion with at least two of the following signs: — Local warmth — Erythema >0.5–2cm around the ulcer — Local tenderness/pain — Local swelling/induration — Purulent discharge Other causes of inflammation of the skin must be excluded

Grade 2/mild

Erythema >2cm and one of the findings above or: — Infection involving structures beneath the skin/ subcutaneous tissues (eg deep abscess, lymphangitis, osteomyelitis, septic arthritis or fascitis) — No systemic inflammatory response (see Grade 4)

Grade 3/moderate

Presence of systemic signs with at least two of the following: — Temperature >39°C or 90bpm — Respiratory rate >20/min — PaCO2