The Risk. Background / Bias. Integrating Wound Care into a Limb Preservation Initiative 4/24/2009

Transcription

1 Stimulating Wound Granulation: Advances in NPWT and other Measures (Wound Bed Preparation) Charles Andersen MD, FACS, FAPWCA Clinical Prof of Surgery UW, USUHS Chief Vascular/Endovascular/ Limb Preservation Surgery Service Medical Director Wound Care Clinic, Madigan Army Medical Center Background / Bias A Vascular Surgeon with 13 years of experience in a Limb Preservation Initiative Limb Preservation is a team sport requiring a multidisciplinary approach A Limb Preservation Initiative can decrease the rate of major amputations Wound Care is a critical component of a limb preservation program Like trauma, Wound Care requires an Integrated Systemic Approach The Risk ULCER INFECTION AMPUTATION As Vascular Surgeons we have focused on The importance of timely and adequate revascularization. Wound care is another Important component of a Limb Preservation Initiative Integrating Wound Care into a Limb Preservation Initiative Requires personnel dedicated to wound care that are part of the Limb Preservation Team (NOT OUT OF SIGHT, OUT OF MIND) Requires wound care education Requires an integrated systemic approach 1

2 Systemic, Integrated Approach to Wound Care Assessment: Primary Assessment Wound characteristics and Etiology Secondary Assessment Evaluation of all systemic factors that can have a negative impact on Wound healing Wound Bed Preparation Wound Closure Primary Assessment Determine the Etiology Failure to identify and correct the etiology of a wound can lead to failure to heal or a recurrence. Neuropathic diabetic ulcers failure to off load will delay or prevent healing or lead to an early recurrence. Venous Ulcers failure to apply external compression and/or correct the underlying disease will lead to recurrence Secondary Assessment Identification of systemic negative healing factors Many times the wound is a manifestation of a chronic Illness. (Cancer) Example poor nutrition or diabetic control in a diabetic patient (Nutrition) Vascular assessment in any lower extremity wound If a wound is failing to heal repeat the primary and secondary assessment. Wound Bed Preparation The management of a wound to accelerate endogenous healing or to facilitate the effectiveness of other therapeutic measures Creating an optimal environment for wound healing by utilizing the most effective therapeutic options. TIME model provides a common language for wound bed preparation (developed by the International Advisory Panel on Wound Bed Preparation) 2

3 TIME Model T Tissue - Management of non viable or deficient tissue I Infection or Inflammation M Prolonged moisture imbalance E non advancing or undermined epidermal margin. Extracellular Matrix (ECM) Imbalance T Tissue - Management of non viable or deficient tissue Devitalized Tissue Growth media for bacteria Release endotoxin Production of biofilm Produce inhibitors of growth factors Debridement A Critical Component of Wound Care Aggressive Debridement Sets the Stage Decrease bacterial load Decrease production of growth factor inhibitors Increase production of growth factors Out patient clinic debridement 3

4 Outpatient Debridement New Tools I Infection or Inflammation Wound cleansing Weekly antiseptic at time of dressing change Select dressings: Silver and Iodine Maintenance debridement NPWT Granufoam Silver M Moisture Balance Basic Wound Care moist wound care environment Avoid desiccation hydrogel or moisture- retentive dressings Avoid maceration absorptive dressings (alginate) NPWT Provides moist wound care environment with a decreased requirement for dressing changes E ECM Balance Dressings that support ECM by sequestering or inactivating excessive MMPs Advance wound care products adding ECM Biologic Dressings Living Cell Therapy NPWT removes negative healing factors and helps restore balance 4

5 Negative Pressure Wound Therapy An important Adjunct in wound bed preparation There has been a significant transition in the way that NPWT is utilized Advanced knowledge of how NPWT works NPWT is often a bridge to other types of wound closure Understanding Science and Mode of Action of NPWT Two Distinct Modes of Action Big Picture The Wound Mechanical Macro Strain Little Picture The Cells Physiologic Micro deformation Big Picture Mechanical Macrostrain Visible alteration occurs when negative pressure contracts the foam, drawing the wound edges together up to 33% decrease in the size of the wound Decreases wound margins Removes exudate Removes infectious material Maintains a moist wound care environment Little Picture -Physiologic Action Microstrain Tissue micro-deformation at the cellular level leading to cell stretch Modifies cellular receptors (use of biomechanics to obtain a biological response) Tissue expanders Bone extraction 5

6 Microstrain most elements exposed to VAC Therapy experienced deformations of 5-20% (MIT and Harvard) Microstrain The finite element model showed that most elements stretched by V.A.C. application experienced deformations of 5 to 20 percent strain, which are similar to in vitro strain levels shown to promote cellular proliferation. Source: Saxena, et. al, Vacuum-Assisted Closure: Microdeformations of Wounds and Cell Proliferation, J.P.R.S., October, Invitro data. May not be indicative of outcomes. Micro-Strain Micro-Strain Enhances Cellular Bio-responses Micro- deformation Micro- strain induces bio-response of integrins (cell surface receptors) to generate secondary messengers increasing rate of mitosis of cells in the wound bed Cellular Response to Micro-strain Activation of Pathways by Shear Stresses 1 1 Chen, et al., JBC. 274: , 1999 V.A.C. Therapy generated micro-deformation directly stimulates cellular proliferation Proliferating fibroblast and endothelial cells form granulation tissue Integrin activated signaling pathways and transmission of mechanical stress Structural changes in cytoskeleton Down-regulation of cell cycle inhibitors Activate genes required for G1/S transition Saxena V. et al. Plastic and Reconstructive Surgery, 2004; 114(5): Fibroblast proliferation and angiogenesis 6

7 Cellular Response to Negative Pressure Therapy Negative Pressure through a foam interface creates uniform microdeformation of cells. Micro deformation results in increased formation of blood vessels, inhanced Gene expression, increased cellular energy and increased release of growth factors. Complicated TMAs Wound Bed Preparation Lessons Learned Early debridement, aggressive wound bed preparation and expeditious closure decreases osteomyelitis and amputation Infected TMA Outpatient ambulatory STSG Four days post STSG 7

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9 Tibialis Anterior Tibialis Anterior Peroneus Longus & Brevis Peroneus Longus Case - NSTI of the Foot in Association with Colon Cancer TR 61 y/o diabetic female Awakened with right foot pain, fever, chills and nausea No history of trauma or surgery to foot Noted bluish discoloration of 4 th and 5 th toes with extension onto the dorsum of the foot Initial surgery amputation of 2 nd 5 th toes at MTPJ joint with debridement of skin and fascia Associated Colon Cancer Clostrium Septicum NSTI Foot (Clostridium Septicum) 9

10 NSTI foot NSTI Foot Living Cell Therapy Wound Bed Preparation NSTI Foot Wound bed preparation 10

11 NSTI Foot -Reconstruction WB Surface Defect Fillet of Toe(s) Flap Conclusion Wound care requires an integrated systemic approach Wound bed preparation is the first step to wound healing TIME Model outlines the important steps in wound bed preparation Advances in wound care techniques: New Debridement Tools, NPWT and Biologic dressings can aid in more rapid wound bed preparation and wound closure and be an adjunct to Limb Preservation. Thank you Madigan Army Medical Center Tacoma. Washington 11