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NEW DRESSINGS FOR WOUND
MANAGEMENTMAX BUSH, VMD
DEPARTMENT OF SURGERY
UPSTATE VETERINARY SPECIALTIES
OUTLINE• Introduction
• Pathophysiology of wound healing
• New management paradigms
• Primary dressing materials
• Honey
• Calcium Alginate
• Vacuum Assisted Closure (Negative Pressure Wound Therapy)
• Summary
WOUND HEALING• Complex biologic process by which tissue attempts to restore
function and structural integrity after injury
• Organized into phases, which overlap
PHASES OF WOUND HEALING• Inflammatory
• Removal of contaminants and dead/damaged tissue
• Proliferative
• Restoration of blood flow, ECM, and epithelium
• Maturation (Remodeling)
• Recovery of pre-wound strength
INFLAMMATORY PHASE• Begins at time of
wounding
• Tissue disruption
• Coagulation cascade
• Platelets adherence, aggregation, degranulation
• Neutrophils (24-48 hours)
• Bactericidal: ROS
• ECM breakdown
• Phagocytosis of bacteria and debris
• Cytokine release, prolonging inflammation
Inflammatory Phase
PROLIFERATION PHASE• Days 4-12 (Duration variable)
• Wound size, location, age, health
• Predominant Cell Types
• Fibroblasts, endothelial and epithelial cells
• Capillary ingrowth, collagen production, wound contraction and coverage
PROLIFERATION PHASE
REMODELING PHASE
REMODELING PHASE• Strengthening of collagen
• Conversion of matrix from thin, weak tissue to more organized rigid framework.
• Collagen synthesis complete by 4-5 weeks post injury –
maturation can continue for 12-18 months.
• Matrix strength improves as collagen is reabsorbed and redeposited along stress lines of the tissue.
• week 1: 3%
• week 3: 30%
• week 12: 80%
IMPEDIMENTS TO HEALING• Local:
• Mechanical factors
• Wound perfusion
• Tissue viability
• Infection
WOUND ASSESSMENT
• Location
• Exudate
• Infection
Culture and Sensitivity
• Stage
Does the wound require
additional debridement?
• What is the goal of the bandage?
MOIST WOUND HEALING PARADIGM SHIFT
• Wet to dry bandages
• Non-selective mechanical debridement
• Destroy epithelial cells
• Can leave foreign material in the wound
• Painful
• Inefficient
• Increase risk of nosocomial infections
• Remove wound fluid
• Reduce temperature
MOIST WOUND HEALING BENEFITS
• Improves resistance to infection
• Facilitates autolytic debridement
• Selective
• Preserves wound fluid
• Autolytic enzymes
• Growth factors
• Systemic antibiotics
MOIST WOUND HEALING BENEFITS• Increases collagen synthesis and
fibroblast proliferation
• Hastens angiogenesis and wound
contraction
• Reduces pain
• Reduces scarring
• Faster healing
SELECTION OF A DRESSING• Dressing should match the characteristics of the wound:
• Stage
• Exudate level
• Location
• Patient temperament
• Client compliance
PETROLATUM IMPREGNATED GAUZE
HYDROGELS
HYDROCOLLOIDS
• Biocompatible hydrophilic polymersCarboxymethycellulose
• Powders, pastes, sheets• Absorbs exudate, conforms to wound
• Can cause maceration if gel overlaps skin edges
CALCIUM ALGINATE
• Derived from Algae
• Non-occlusive, non-adhesive, highly absorptive
• Forms viscous hydrogel
• Can be inserted into deep cavitated wounds
CALCIUM ALGINATE• Moderate to heavy exudate
• Many have silver ions to increase anti-microbial activity
• Hemostatic capability; can be applied post operatively
HYDROFIBER
HYDROFIBER
• https://youtu.be/cdUg6crVYz8?t=52
HONEY DRESSINGS
PHYSICAL/CHEMICAL CHARACTERISTICS
• Sugar concentration
• Osmotic effects
• Acidification
DEBRIDEMENT
• Osmotic effect pulls fluid into the wound
from the interstitium
• Facilitates conversion of plasminogen to plasmin
IMMUNOSTIMULATORY
• Upregulation of
• TNFa
• IL-1B
• IL-6
• TGF-a
ANTI-INFLAMMATORY
• Phenolic compounds inhibit TNFa
• Apalbumin inhibits phagocytosis by macrophages
• Decrease inflammatory cells at the wound cells
• Reductions in pain, edema, exudate, scarring
ANTIBIOSIS
• Effective against MDR Staph, Enterococci, Pseudomonas
• MOA
• Osmotic desiccation
• Acidity
• Enzymatic activity
• Plant factors
BIOACTIVITY• Methylglyoxal – cytotoxic chemical, water soluble
• Maintains antibiotic efficacy above MIC even when diluted by wound fluids
• Effective against MDR bacteria
• MRSA
• Coagulase-negative Staphylococci
• VRE
• ESBL-E coli
• No resistance acquired
NEGATIVE PRESSURE WOUND THERAPY
• Uses suction to modify the wound environment
• Macrostrain
• Microstrain
NWPT THERAPY
• Open cell foam sealed with adhesive,
occlusive dressing
• Helpful to use stoma-paste
• Suction tubing is connected to canister,
creating closed system
NWPT THERAPY
• Application of subatmospheric pressure
• Continuous or intermittent
• Dressing is changed q3-4d
• Standard pressure is -125mmHg
NEGATIVE PRESSURE WOUND THERAPY
• Fluid removal
• Physical tension
• Microdeformation
VAC USES
• Degloving
• Chronic wounds
• Severe abscess
• Incisions with risk of dehiscence or infection
• Traumatic wounds
• Ulcers
• Infected lacerations
• Flaps and grafts
SUMMARY• Wide variety of wound dressings
• Assess the wound
• Match its needs
• Moist Wound Healing
• Speed wound healing
• Reduce client cost
• Improve patient outcomes
FURTHER INFORMATION
• Moist Wound Healing: The New Standard of Care
• Bonnie Grambow Campbell,
Today’s Veterinary Practice July/August 2015
• Good article discussing MWH
• Guidelines for dressing selection and timing of changes
QUESTIONS?