new dressings for wound management

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?