Diabetic Wounds: A Multidisciplinary Approach

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Diabetic WoundsA Multidisciplinary Approach
Poudre Valley Hospital Wound Conference May 19th,
2006

• James R. Holm, MD, FACEP
• Medical Director, Hyperbaric Medicine
• Physician, Emergency Medicine and Wound Care
• Memorial Hospital, Colorado Springs, CO
• www.hbodoctor.com

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Background

• Education
• Georgetown University Medical School, 1985
• Northwestern University Residency in EM/IM, 1989
• Board Certified
• Internal Medicine
• Emergency Medicine
• Undersea Hyperbaric Medicine

• Medical Practice
• Emergency Medicine since 1989
• Hyperbaric Medicine since 1997
• At Memorial Hospital since 2002
• Wound Healing Center
• Diving Experience
• 1969 NAUI SCUBA Certified
• 1978 NAUI/PADI Instructor

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Diabetic Foot Wound
56 yo male with longstanding diabetes presents to
ED with painless swollen discolored foot.
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Introduction

• Diabetic Wound Problem and the Team
• Introduction to Wound Healing
• Peripheral Neuropathy Diabetic Management
• Vascular Evaluation and Treatment
• Treatment of Infection
• Debridement
• Adjunctive Therapy (Growth factors, VAC, HBO)
• Conclusions

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Cost of Diabetic Wounds

• 15 million people in the US have DM
• Half do not know they have diabetes
• 15 of these patient will be admitted for
  diabetic foot infections over their lifetime
• Annual cost for diabetes care in US exceeds 50
  billion dollars
• Annual cost for diabetic foot associated
  complications exceeds 1 billion dollars

Faries, Am J Surg 2004 187 34S-37S
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Limb Salvage

• Amputations
• Toe
• Metatarsal (ray)
• TMA
• Choparts
• Lisfrancs
• BKA
• AKA

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The Team

• Primary Care Team (PCP, Endo, Renal)
• Wound Specialist
• Podiatrist or Orthopedist
• Infectious Disease
• Vascular Surgeon
• Plastic Surgeon
• Non-physicians (Diabetes Education, PT, OT)

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Introduction to Wound Healing
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Acute Wounds in Normal Hosts
Most will heal no matter what you do. Usually
will heal in days to weeks. In impaired hosts
healing is measured in weeks to months.
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Types of Wounds

• Traumatic wounds
• Burns, bites stings
• Venous ulcers
• Diabetic ulcers
• Pressure ulcers
• Arterial ulcers
• Connective tissue disorders (RA, SLE,
  Scleroderma)
• Malignancy wounds
• Some or all of the above

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Stages of Wound Healing

• Clotting
• Inflammatory
• Proliferative
• Remodeling Cross linking

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Phases of Wound Healing
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Healing and Growth Factors
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Wound Size and Depth
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Wagner Grading System
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What is a Problem Wound
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Easy to Manage Always Good Outcomes
Healthy Wound
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6
Problem Wound
4
2
Impossible to Manage Almost Always Bad Outcomes
Futile Wound
0
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Factors for Poor Wound Healing
Inadequate nutrients Inadequate
energy Inadequate protein Tissue hypoxia Low
blood flow Eschar or exudates Consumption of
O2 Tissue desiccation Occurs with open
wound Impedes epithelial migration
Wound exudates Release of proteases Injury of
new tissue Wound infection Impaired local
defense Exposure to microbes Wound
trauma Environmental insult Use of toxic
chemicals Traumatic dressing changes
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Peripheral NeuropathyDiabetic Management
Hunt D, Using evidence in practice Foot care in
diabetes. Endocrinol Metab Clin N Am
200231603-611
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Peripheral Neuropathy

• Loss of Protective Sensation (LOPS)
• Loss of Motor Function (foot intrinsic muscles)
• Change in the Anatomy of the Foot
• Cavus deformity with increase pressure on MT
  heads
• Claw toe position
• Charcot deformity
• Loss of Autonomic Function
• Decreased sweat leading to dry cracked skin
• Vasomotor dysfunction with AV shunting

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Causes of Diabetic Ulcers
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A Neuropathic Ulcer of the Left Foot of a Patient
with an Amputated Hallux
Caputo, G. M. et al. N Engl J Med 1994331854-860
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Sensory Examination Neuropathy
Semmes Weinstein monofilament test or loss of
vibratory sensation
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A Simple Office Test to Determine Whether a
Patient Has Protective Sensation in the Feet
Caputo, G. M. et al. N Engl J Med 1994331854-860
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Orthotics Custom Shoes

• If there is a neuropathy then regular shoes
  will not do. Patient should have custom shoes
  and/or inserts.
• Their feet examined at each visit and see a
  doctor at the earliest sign of a wound, callus,
  or blister.

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Cross-Section of a Total-Contact Cast Formed to a
Patient's Foot
Caputo, G. M. et al. N Engl J Med 1994331854-860
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Off Loading Neuropathic Ulcers

• Mueller MJ, Total contact casting in treatment of
  diabetic plantar ulcers controlled clinical
  trial. Diabetes Care 198912384-8
• Randomized trial of TCC of 40 patients with
  noninfected plantar foot ulcers
• TCC Initial cast changed in 5 to 7 days then
  every 2 to 3 weeks until healed
• Usual Care Education, accommodative footwear,
  dressing changes, crutches or walker
• Healing Rate TCC 91 vs 32 (difference 59,
  95 CI 31-87)

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Off Loading Neuropathic Ulcers

• Caravaggi C, Effectiveness and safety of a
  nonremovable fiberglass off-bearing cast versus a
  therapeutic shoe in the treatment of neuropathic
  foot ulcers a randomized study. Diabetes Care
  2000231746-51
• Randomized trial with 50 patients with
  noninfected plantar foot ulcers using a
  fiberglass cast vs. cloth shoes with rigid soles
  and off-loading insoles
• 30 day healing rate 50 vs 21 (difference 29,
  95 CI 1.4-50)

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Off Loading Neuropathic Ulcers

• Armstrong DG, Off-loading the diabetic foot
  wound a randomized clinical trial. Diabetes Care
  2001241019-22
• 63 patient with noninfected plantar wound using
  TCC vs. removable cast walker.
• Healing at 12 weeks 89 vs 61 (difference 28,
  95 CI 5-51)

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Vascular Evaluation and Treatment
Gibbons GW, Lower extremity bypass in patients
with diabetic foot ulcers. Surg Clin N Am
200383659-669
Faries PL, The role of surgical revascularization
in management of diabetic foot wounds. Am J of
Surg 200418734S-37S
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Peripheral Arterial Circulation
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Peripheral Vascular Disease

• The prevalence of PVD increases with age
• 32 (40-59 years)
• 82 (60-69 years)
• 192 (over 70 years)
• 1. Rosenfield, K and Isner JM. Chap. 97 Textbook
  of Cardiovascular Medicine 1998
• 2. Criqui et al. Circulation 198571(3)510-515

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Peripheral Vascular Disease
Relative Risk Factors
Smoking
Race
Hypertension
Gender
Diabetes
Age1
Hyperhomocysteinemia
Hyperlipidemia2
1. Calculated relative risk increase at 5-year
intervals 2. Rel. Risk is 1.1 per 10mg/dL
increase in total cholesterol
From Newman et al. Circulation 1993 Hiatt et
al, Circulation 1995 Graham, JAMA 1997
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PVD Diagnostic Tests

• Non-invasive tests1
• ABI (Ankle/Brachial Index)
• Exercise Test
• Segmental Pressures
• Segmental Volume Plethysmography
• Duplex Ultrasonography
• MRA (Magnetic Resonance Arteriography)
• CTA (CT Angiography)
• Invasive tests1
• Peripheral Angiogram
• Intravascular US
• 1. Krajewski and Olin Chapter
  11 Peripheral Vascular Disease. 2nd ed. 1996

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Doppler Evaluation ABI
Pulses maybe unreliable
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ABI (Ankle-Brachial Index)
Rice, KL and Walsh ME. Nursing 98, Feb. 1998
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PVD Diagnostic TestDuplex Scanning
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PVD Treatment Options

• Medical
• Risk Factor Modification
• Exercise Therapy
• Drug Therapy
• Endovascular Therapy
• Peripheral Transluminal Angioplasty
• Peripheral Stenting
• Atherectomy
• Thrombolytic Therapy
• Surgery
• Bypass grafts
• Amputation
• Endarterectomy

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The SilverHawk Plaque Excision System

• FDA-cleared for use in the peripheral arteries
• Any lesion length and location treatable
• Intuitive design and operation
• Single device can treat multiple lesions and
  vessels

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Vascular Disease in Diabetes
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PVD in Diabetes

• Tend to be more distal (tibial)
• Often spares the pedal arteries
• Need to get imaging down to foot level
• May be amenable to pedal bypass
• May lack claudication symptoms
• Usually one level above disease
• May be obscured by neuropathy
• Very common cause of nonhealing wounds

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Amputation and Bypass Trends
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Vascular Surgery Reconstruction Results

• Type of Reconstruction
  Patency Rate
• Ao-Iliac/Ao-fem (Synthetic)
  80-90 (5 yrs)
• Fem-pop Above Knee (Synthetic)
  60-70 (5 yrs)
• Fem-pop Above Knee (Autologous Vein) 70-80(5
  yrs)
• Fem-pop Below Knee (Synthetic)
  45 (5 yrs)
• Fem-pop Below Knee (Autologous Vein) 75 (3
  yrs)
• Fem-tib (Autologous Vein)
  50-70 (3 yrs)

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TCOM Study
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Transcutaneous O2 Measurements (TCOM)

• Control indicates systemic oxygenation
• TCOM gt 40 mm Hg - normal healing
• TCOM 30-40 - variable response
• TCOM lt 30 - failed primary or secondary healing
• static and dynamic measurements with oxygen
  challenge

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TCOM Example
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Treatment of Infection
Frykberg RG, An evidence-based approach to
diabetic foot infections. Am J Surg
2003186/5A44S-54S
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Treatment of Infection

• Determine if there is
• Wound Infection (define tissue involved)
• Wound Colonization (bug in normal wound)
• Carrier State (bug in normal anatomy)
• Cultures
• Best to obtain tissue cultures from surgery or
  debridement (gt105 colonies / gram tissue)
• Culture deep in the wound and not skin flora

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Spectrum of Bacterial Burden
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Wound Infection Cultures

• Superficial wound
• Microflora overview
• Greatest bacterial burden

• Deep wound
• True pathogen isolation most likely

As the number of isolates from a culture
increase, so decreases the specificity and value
of the culture
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Culture Techniques

• Debride and irrigate before culturing
• Culture techniques
• Semi-quantitative Swab
• Quadrant plated
• Rare to heavy(1-4) reporting
• Deep tissue semi-quantitative
• Reasonable sensitivity and specificity
• Can include anerobes
• Quantitative culture

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Topical vs Systemic Therapy

• Colonization-No treatment indicated
• Critical Colonization
• Impaired wound healing but no systemic response
  indicating infection
• Topical therapy appropriate
• Infection
• Systemic antibiotic therapy plus appropriate
  wound measures
• Topical agents treat critical colonization not
  active wound infections

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Cellulitis and Soft Tissue Infections

• Often caused by trauma and a pre-existing ulcer
• Often is deeper then it appears
• Neuropathy masks symptoms
• Fever and elevated WBC maybe absent
• Debride blisters and callus and look for tracts
  to bone, ligament or tendon
• Treatment is debride, culture, and antibiotics
• Consider vascular insufficiency
• Consider underlying osteomyelitis

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Infection and Osteomyelitis

• Plain film rarely useful (unless late), good for
  FBs
• Bone scan nonspecific
• MRI can be helpful
• T1 weighted image (low signal intensity)
• T2 fat-saturated image (hyperintense signal)
• T1 fat-saturated image post-gadolinium
  (enhancement)

Chatha DS, MR Imaging of the Diabetic Foot
Diagnostic Challenges. Radiol Clin N Am
200543747-59
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Osteomyelitis MRI Findings
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Osteomyelitis in Diabetic Foot Ulcers

• Grayson ML, Probing to bone in infected pedal
  ulcers. JAMA 1995273721-3
• Swab Test If you can palpate small bones of
  the feet in diabetics, consider it osteomyelitis
  until proven otherwise
• 95 specific but not sensitive

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Gas Gangrene and Necrotizing Fasciitis
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Deep Cutaneous Infections

• Necrotizing fasciitis/Streptococcal gangrene
• Gangrenous cellulitis
• Bacterial synergistic gangrene
• Clostridial cellulitis/myositis
• Best to describe the structures involved and the
  bug (once isolated)

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Wound Debridement
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Types of Debridement

• Mechanical
• Sharp debridement
• Whirlpool or lavage
• Wet to dry dressing
• Chemical
• Autolytic bodies own enzymes through moist wound
  healing environment
• Enzymatic
• Collanenase (Santyl)
• Fibrinolysin (Elase)
• Fibrinolysis DNAase (Elase with chloromycetin)
• Papain Urea (Accuzyme)
• Biological
• Maggot Debridement Therapy (MDT)

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Sharp Debridement

• Gloves
• Scalpel
• Forceps
• Iris Scissors
• Curette
• Cautery

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Adjunctive Treatments

• Growth Factors
• Hyperbaric Oxygen Therapy (HBOT)
• Biological Dressings
• Negative Pressure Therapy (VAC)

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Platelet Derived Growth Factor

• rhPDGF beta beta becaplermin (Regranex)
• Comes in 0.01 gel (15gm tube) kept refrigerated
  and applied 1 x qd with a thin coat covered by a
  moistened saline dressing
• Wound should have adequate blood supply (pulses
  and/or TCOM gt 30 torr) and be free of necrotic
  tissue
• Expensive but tube lasts a long time and cost of
  continued open wound or amputation is far worse

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Platelet Derived Growth Factor(Regranex gel)

• Works best with frequent debridement and good
  overall wound care
• Steed, JACS, July 1996

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Multiplace Chambers
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Monoplace Chambers
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Effects of HBO

• Hyperoxygenation
• Vasoconstriction
• Neovascularisation
• Altered Cellular Function
• Enhanced WBC Killing
• Decreased WBC Adhesion
• Pressure Gas Gradients

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HBO and Diabetic LE Ulcers

• Non-blinded randomised controlled trial without
  intention-to-treat.
• Adult diabetic patients with problematic foot
  ulcers referred to a major diabetic foot clinic
  in Italy.
• Control group (N 33 32 analysed) A
  comprehensive diagnostic-therapeutic protocol by
  a multi-disciplinary team including diabetic
  control, wound care, podiatry and vascular
  surgery.
• Experimental group (N 35 34 analysed) As
  above with the addition of hyperbaric oxygenation
  at 2.2 to 2.5 ATA for 90 minutes daily until
  healing established or treatment abandoned in
  favor of amputation. Mean number of treatments
  was 38 (/- 8)

Faglia E, et al. Adjunctive systemic hyperbaric
oxygen therapy in the treatment of diabetic foot
ulcer. A randomized study. Diabetes Care
1996191338-43
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Faglia Results

• Results
• Amputation Rate
• Control Group 11 (33.3) had major amputations
  (7 BKA, 4 AKA)
• HBO Group 3 (8.6) had major amputations (2 BKA,
  1 AKA)
• P0.016
• Transcutaneous oxygen tension improvement on
  dorsum of foot at completion of treatment
• Control 5.0 /- 5.4 mmHg
• HBO 14.0 /- 11.8 mmHg
• P0.0002

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Negative Pressure Therapy
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VAC Definition

• A non-invasive active therapy using controlled,
  localized subatmospheric pressure to promote
  moist wound healing

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How does the VAC work?

• Helps promote granulation tissue formation, which
  aids in the wound healing process
• Applies localized negative pressure to help
  uniformly draw wounds closed
• Helps remove interstitial fluid and infectious
  material
• Provides a closed, moist wound healing
  environment
• Increased epithelial tissue migration

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VAC Example
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Conclusions

• Address diabetic wounds aggressively
• Do a complete exam of the diabetic wound patient
  (vascular, sensory, etc) then the wound
• If neuropathy is present then prevention and
  off-loading is critical
• Evaluate arterial status on all wound patients
  with pulses, dopplers, and TCOMs if needed
• Consider vascular intervention and pedal bypass
• Debride early and often
• Consider PDGF, VAC and HBO evaluation for
  difficult wounds
• Diabetic management and prevention is key