Wound Management Flashcards
What regulates the process of wound healing
Soluble factors
What do abnormalities in wound healing cause?
Scarring
Fibrosis
What six things does wound healing involve?
Initial acute inflammatory response Parenchymal regeneration Re-epithelialisation and cell migration Proliferation of parenchyma and stromal cells Synthesis of ECM proteins Remodelling
What are the three classic stages of wound healing?
Inflammation - 48 hours after injury
New tissue formation - 2 to 10 days
Remodelling/maturation - 1 year or more
Describe the basic process of inflammation in wound healing
Hypoxic with a fibrin clot
Abundant bacteria, neutrophils and platelets
Describe the basic process of new tissue formation in wound healing
Surface scab
Most inflammatory cells moved away
New blood vessels predominate
Epithelial cells migrate under scab
Describe the basic process of remodelling in wound healing
Disorganized collagen made by fibroblasts that move into wound
Wound contracted near surface - widest part is deep
Re-epithelialized wound raised
What are the first four things to happen during wound healing?
Bleeding
Coagulation
Platelet activation
Complement activation
What two things care present or occurring during inflammation around day 1 of wound healing?
Granulocytes present
Phagocytosis occurring
What two things are present around day 3 of inflammation?
Macrophages
Cytokines
What four things are occurring around day 4-5 of new tissue formation?
Fibroplasia
Angiogenesis
Re-epithelialisation
ECM synthesis
What is occurring between days 30-100 in wound healing and what is increased and decreased?
ECM remodelling - increased tensile strength - decreased cellularity and vascularity
What cells are involved in coagulation?
Platelets
What cells are involved in inflammation?
Platelets
Macrophages
Neutrophils
What cells are involved in new tissue formation?
Macrophages Lymphocytes Fibroblasts Epithelial cells Endothelial cells
What cells are involved in remodelling?
Fibroblasts
What are the initial events in wound healing that lead up to coagulation?
Death of some epithelial and dermal cells
Damage to collagenous fibres in tissue
Small vessel rupture - increased vasodilation and permeability
Release of blood into wound and surrounding tissue
Coagulation
Formation of fibrin clot
What three things happen during coagulation?
Platelet deposition and aggregation
Platelets degranulate
PDGF, TGFb and fibronectin released
What are the key players in the inflammation stage of wound healing?
Monocytes
Macrophages
When are lymphocytes recruited in wound healing and what are they important in?
Recruited later
Important in early remodelling phase
What are the five roles of macrophages in wound healing?
Removal of wound debris Cell recruitment and activation Phagocytosis Angiogenesis Matrix synthesis regulation
Describe the process of re-epithelisation of the skin
Single keratinocyte layer migrates under fibrin clot
Travels from wound edges across wound to re-surface area
During and after this differentiation and stratification of neo-dermis occurs
What are the five roles of keratinocytes in skin healing?
Migration/proliferation ECM production Growth factor/cytokine production Angiogenesis Release of proteases
How does the fibrin clot help with re-epithelialisation and angiogenesis?
Secrete factors to promote re-epithelialisation
Allows endothelial cell migration into wound
Describe angiogenesis in wound healing
Begin as endothelial cell buds
Move towards wound space
Macrophages and keratinocytes provide stimuli
How does angiogenesis occur in other places?
Capillaries sprout from parent vessels Initiated by production of growth factors from nearby cells Endothelial cells produce proteases Cells migrate towards the growth factors Cells proliferate and divide Cells from tubes
Describe the early tubes formed by cells in angiogenesis
Leaky at first
Granulation tissue usually oedematous
Change in integrity when acquire support from surrounding cells
What occurs during fibroplasia in wound healing?
Fibroblasts migrate in and replicate
Synthesise and deposit ECM
Fibroblasts differentiate into myofibroblasts
Express contractile protein and effect wound closure
What are the four roles of fibroblasts in connective tissue formation and remodelling?
ECM production
GF and cytokine production
Angiogenesis
Protease release
When is granulation tissue established in wound healing?
Within 3-5 days post injury
Describe granulation tissue appearance
Pink, soft granular tissue
First appears beneath scab
Comprised of fibroblasts, thin walled capillaries and loose ECM
What is part of normal wound healing in the horse?
Exuberant granulation tissue - proud flesh
What is a normal and inevitable outcome of wound repair in mammals?
Scarring process
What is prolonged scarring called?
FIbrosis
What does scar formation rely on?
Rate of collagen synthesis vs. its rate of degradation
What extrinsic factors can modify wound healing?
Infection Nutrition Glucocorticoids Mechanical factors Poor blood flow Pathogens
How can the tissue type affect wound healing?
Total repair only possible when tissue contains labile cells
If only permanent cells only scarring can occur
Describe the basic process of re-epithelialisation
Blood forms clot blocking pathogen invasion
Inflammatory phase begins
Leukocyte influx
Endothelial cells migrate causing angiogenesis
Fibroblasts activated causing proliferation, migration and construction of granulation tissue
Epithelial cells migrate to from thin sheet and restore surface integrity
What are the six healing factors involved in wound healing?
EGF - epidermal/epithelial growth factor - mitogenic for epithelial cells and fibroblasts
PDGF - platelet derived growth factor - induces migration/proliferation of fibroblasts, vSMC and monocytes
FGF - fibroblast growth factor - induces fibroblast growth and angiogenesis
TGFbeta - transforming growth factor beta - promotes fibroblast migration/proliferation and ECM synthesis
VEGF - vascular endothelial growth factor - promotes angiogenesis
IL-1/TNFalpha - interleukin-1 and tumour necrosis factor - induces fibroblast proliferation
What are the seven regulators of wound healing?
Coagulation component Endogenous tissue factors Growth factors Interactions with ECM Cell-to-cell contacts and gap junctions Mechanical stimulation Oxidative stress
What are Esmarch’s five principles of wound management?
Non-introduction of anything harmful Tissue rest Wound drainage Avoidance of venous stasis Cleanliness
What are Halsted’s principles of surgery?
Haemostasis Aseptic technique Light touch Supply of blood preserved Tension-free closure Even tissue apposition Dead space obliterated
What are the ten major complications that can occur with wound healing?
Haemorrhage and haematoma Swelling and oedema Seroma Dehiscence Infection Tissue necrosis Scarring and contracture Draining tracts Exposed bone Non-healing wounds
How can acute marked haemorrhage affect wound healing?
Results in hypovolaemia
Affects wound healing
Potentiates wound infection
How can overzealous haemostasis affect wound healing?
Results in poor tissue viability
What ways can the presence of a haematoma influence wound healing?
Separates wound edges
Puts pressure on wound edges - necrosis and dehiscence
Prevents skin graft adherence to recipient bed
Barrier to migration of leukocytes and capillaries
Provides growth medium for bacteria
Describe conservative treatment for minor to moderate bleeding
Direct pressure Light bandage for up to 12 hours Restriction of movement of the body part Restriction of movement of the patient Investigate underlying coagulopathy Administration of IV fluids or bloods
What circumstances dictate surgical management of bleeding?
Arterial bleeding that is severe or non-responsive to conservative management
Dehiscence of the wound due to pressure
Development of compartment syndrome
Secondary infection of the haemoatoma
What can be the causes of oedema during wound healing?
Damage to regional blood vessels or lymphatics
Vascular occlusion - tight sutures/restrictive bandage
How can oedema affect wound healing?
Potentiates wound dehiscence
Delays wound healing by affecting wound vascularity
What wounds is post-operative oedema more marked in?
Regional mastectomy with tissue undermining
Reverse saphenous conduit flap
Free skin graft during plasmatic imbibition
Large distal limb wounds allowed to heal by second intention
Excision of lymph nodes
What should oedema be differentiated from?
Local infection
Cellulitis
What should regional oedema prompt an investigation of?
Things draining the region for pathological processes causing occlusion - veins, lymphatics and lymph nodes
What should generalised oedema prompt an investigation of?
Presence of hypoproteinaemia
Cardiac disease
What can moderate oedema benefit from?
Massage
Hot and cold packing
Physiotherapy
What may be needed for oedema treatment?
Removal of sutures contributing to vascular occlusion
Subsequent open wound management
Alternative closure plan
What is seroma?
Collection of serum and tissue fluid
Accumulates in a dead space and between tissue planes of a wound
How do seromas present?
Soft, fluctuant, non-painful swelling
Beneath skin incision
2-5 days after surgery
What factors contribute to the development of a seroma?
Inflammation Lymphatic injury Poor haemostasis Excessive tissue dissection Undermining creating dead space Traumatic surgical technique Poor tissue apposition Failure to manage dead space Constant motion at the surgical site Loose skin and tissue at the surgical site Use of suture material and mesh implants Repeated trauma to tissue from suture knots Release of vaso-active inflammatory mediators from mast cell tumour
How can fluid collecting between tissue layers delay wound healing?
Prevents tissue apposition
Prevents adherence of free skin graft to recipient bed
Puts pressure on wound edges increasing dehiscence risk
Interferes with blood supply to tissues
Inhibits influx of leukocytes potentiating wound infection
Which seromas require treatment?
Larger seromas
How should larger seromas be treated?
Drainage by aspiration
Management of dead space by bandage
Limit movement of animal and affected part
Drainage by indwelling drain
Removal of sutures and heal by second intention
What is dehiscence?
Breakdown of surgical wounds
What are the two main causes of wound dehiscence?
Excessive forces on the incision
Poor wound holding strength
When does most wound dehiscence occur?
3-5 days post surgery
What may be the initial signs of dehiscence?
Serosanguinous discharge from wound edges Non-painful subcutaneous wound swelling Necrosis of wound edges Extensive cutaneous bruising Serum below skin
What does the treatment of dehiscence depend upon?
Tissue layer that has suffered dehiscence
Cause of dehiscence
What should be done if dehiscence exposes vital structures to trauma?
Wound closed as soon as possible
How should dehiscence be treated if it occurs in the skin and subcutaneous tissue and is contaminated or infected?
Treat as an open wound
How can the risk of dehiscence due to wound infection be reduced?
Choosing delayed primary or secondary closure
Heal by second intention
What are the local signs of a wound infection?
Classical signs of inflammation
Serosanguinous to purulent discharge
Beyond what time does presence of inflammation, pyrexia or wound discharge suggest wound infection?
48 hours
What can be a strong indicator of wound infection?
Serosanguinous discharge from wound 3-5 days post surgery
What is the usual treatment for superficial wound infection?
Open wound management Remove sutures if necessary Debride devitalised tissue Lavage Drain
What may deeper wound infections require for treatment?
Wound exploration
Drain implantation
Samples taken for culture and sensitivity
What is delayed wound infection most commonly caused by?
Infection associated with implant presence - orthopaedics, non-absorbable mesh, non-absorbable suture material
What is another cause of delayed wound infection?
Failure of adequte debridement at first surgery
What is usually the cause of tissue necrosis?
Inadequate blood supply caused by trauma or surgery
How should necrotic tissue be removed?
Debridement of the wound
What are the consequences of not debriding the wound?
Increased infection risk Abscess formation Continued inflammation Additional metabolic load Delayed wound healing Poor cosmetic outcome
Where is excessive scarring not wanted?
Over joints
Near natural body orifices
How can scarring be reduced?
Meticulous atraumatic technique
Infection control
Early wound closure
What is wound contracture?
Loss of function of a body part as a result of excessive scarring
How can wound contracture be prevented?
Early recognition of wounds at risk - wounds near joints and body orifices, larger wounds left to heal by second intention
What can help to prevent contracture?
Early wound closure
What is needed once contracture has occurred?
Z-plasties Scar excision Partial myotomies Temporary splintage Physiotherapy Early return to normal therapy
When do adhesions develop?
When equilibrium between normal fibrin deposition and fibrinolysis is disrupted
What factors cause adhesion by disrupting the equilibrium?
Ischaemia
Haemorrhage
Foreign bodies
Infection
How can adhesion formation be reduced?
Atraumatic tissue handling
Keep tissues moist
Strict asepsis
What is a sinus?
Blind-ending tract that extends from an epithelial surface
What is a fistula?
Communicating tract that extends from one epithelial surface to another
What can draining tracts be associated with?
Large necrotic tissue pockets Resistant bacteria or fungi Underlying osteomyelitis or sequestrum Foreign bodies Foreign materials Neoplasia
What is required with draining tracts?
Surgical exploration
Debridement
Tissue biopsy for culture and histology
What should be done with each draining tract?
Identified
Excised
If not possible - explored, lavage, use open wound management or closure with drain
What is exposed bone most commonly associated with?
Distal limb wounds with gross tissue loss
Caused by shearing and degloving, or extensice necrosis from vascular injury or cellulitis
What may exposed bone be covered by?
Granulation tissue arising from viable periosteum
How can granulation tissue formation over the bone be promoted?
Drilling small holes through the cortex into the medulla
When could granulation tissue take longer to cover exposed bone?
If bone does not have its periosteum
What should be done with exposed bone if it protrudes above the surface of the wound?
If not critical to salvage of body part
Excise to level or below granulation tissue bed
What does successful management of non-healing wounds require?
Identification of factors that are inhibiting healing and removing or correcting them
What can lack of healing be due to?
Neglect
Incompetence
Misdiagnosis
Inappropriate treatment strategies
What are the key causes of the non-healing wound?
Wound infection Necrotic tissue Foreign material Poor blood supply Unrecognized malignancy
What can formation of granulation tissue be impaired by?
Necrotic tissue Devitalised tissue Wound infection Ischaemia Movement
What are delays in fomation of granulation tissue usually due to?
Poor blood supply - caused by trauma, application of fibrosing/caustic chemotherapeutic agents, radiotherapy
How can the surgeon promote formation of a normal healthy granulation bed?
Debridement of necrotic tissue
Control local infection
Preserve viability of tissue in wound
Maintain normal cardiovascular output
How can wound vascularity be improved?
Muscle flaps
Omentalisation
Bring vascularised normal skin tino the wound
What are the two most common factors that prevent or slow wound contraction?
Peripheral countertension due to lack of loose skin around the wound
Restrictive fibrosis which mechanically impairs skin advancement from the wound edges
What factors are associated with delayed epithelialisation?
Necrotic tissue Wound infection Fibrotic scar tissue Poor quality chronic granulation tissue Rpeated surface trauma Loos bandages Tissue desiccation Movement at wound site
How can epithelialisation failuyre be treated?
Debride and lavage Antibiotic therapy Excision of chronic wound bed Re-establishment of new granulation tissue Physical protection of wound Immobilisation of affected part
Where are indolent pocket wounds msot commonly seen?
Inguinal, axillary and flank regions
Particularly in cats
How can indolent pocket wounds be successfully managed?
Control infection
Excise the scar border
Excise restrictive dermal scar
Close wound by suturing skin edges directly to each other
Ancho skin edges to underlying granulation bed
Manage deadspace with drains
Use local skin flaps if can’t achieve primary closure
Omentalisation if vascular supply is compromised
Descibre indolent pocket wounds
Granulation tissue froms with pliable skin around the wound
Surrounding skin becomes elevated from the wound
Skin does not adhere to margins of defect
Cavity lined by granulation tissue forms in hypodermal space
Skin edges will not advance and tend to curl under
Granulation tissue may then become infected
What is a surgical drain?
A temporary implant which provides and maintains a channel of exit for the purpose of removing fluids from a wound
What are the advantages of using surgical drains?
Improved healing rate
Reduced infection rate
What are the problems with surgical drain use?
Underused
Used improperly
What are the indications for use of surgical drains?
Eliminate dead space
Remove fluid from a wound
Detect fluid within a wound
What are the five things to consider when choosing surgical drains?
Wound factors - need, type of fluid, location
Patient factors - tolerance
Hospital environment - availability, post-op care
Drainage system - drain type, method of evacuation
Cost
What are three examples of wounds that leave dead space?
Extensive subcutaneous dissection
Removal of large masses
Reconstruction using flaps
What are the three ways to eliminate dead space?
Surgical means - closure of tissue layers with tacking sutures, insufficient, causes damage to blood vessels, excess suture material
Pressure bandages - if suitable site, short term, too little or too much pressure usually applied
Surgical drains - is the above are not sufficient
What reasons are there that fluid might not be removed at surgery?
Access Incomplete debridement TOo thick Continued production Massive contamination
Why should we remove fluid?
Reduces healing
Increases infection
Antibodies don’t opsonise
Phagocytic function poor
Bacteria grow in fluid
Fluid accumulation may interfere with blood supply
Fluid will prevent flap or graft adherence
What are the four ways that drainage can be achieved?
Open drainage
Fenestration of the skin
Physiological implant
Surgical implant
What are the six ways we can classify drains?
Mechanism of action - passive or active
Type of implant - surface-acting or tube drain
Number of lumens - single or double or triple
Suction system - commercial or home-made
Suction pressure - gravity or low or high
Suction type - closed or vented
What are the advantages of passive and active drains?
Passive - cheap, simple, well tolerated
Active - efficient, use non-dependently, can measure volume
What are the five properties of the ideal drain?
Inert Soft Radiopaque Easy to handle Cheap
How do passive drains function?
Overflow Gravity Pressure differentials Tissue movement Capillary action
What does the function of passive drains depend on?
Surface area
Placement
What is the action of active drains?
External suction evacuates fluid
Passive flow augments active suction
What are the advantages to using active drains?
Increased efficiency if - can’t place dependently, changing dependent point or large volumes of fluid
CLosed system - reduces likelihood of ascending infection
Describe a Penrose drain, the advantages, disadvantages and uses
Penrose drain - flat cylinder, latex or silicone, 1/4”-2” wide, 12-36” long
Advantages - soft and malleable, easily sterilised and doesn’t exert pressure on adjacent structures
Disadvantages - can’t apply suction, limited efficiency, ascending infection more likely, inflammatory reaction greater with latex
Uses - salivary mucocoele and abscess
Describe a strip drain and its advantages and disadvantages
Strip drain - strip of a Penrose drain
Advantages - smaller, higher surface area
Disadvantages - tricky to make, more difficult to handle, structurally weaker
Describe a cigarette drain and its advantages and disadvantages
Cigarette drain - Penrose drain, gauze tape rolled up in end
Advantages - capillarity, inside/outside drain
Disadvantages - inflammation, increases wicking
Describe a dental dam and its advantages and disadvantages
Dental dam - latex rubber sheet, rolled into tubes
Advantages - soft and malleable, easily sterilised, doesn’t exert pressure on adjacent structures, high surface area
Disadvantages - cut to size and roll, difficult to handle
Describe a corrugated drain and its advantages and disadvantages
Corrugated drain - flat, ribbed, rubber or PVC
Advantages - large diameter, variable size
Disadvantages - bulky, foreign material, more rigid causing tissue trauma
Describe a Yeates drain and its advantages and disadvantages
Yeates drain - series of tubes
Advantages - large diameter, variable size, lumina
Disadvantages - bulky, foreign material, rigid can cause tissue trauma
Describe a cylindrical tube drain and its advantages and disadvantages
Cylindrical tube drain - cylindrical tube, 1-13mm wide, rubber or PVC, fenestrations
Advantages - can apply suction
Disadvantages - rigid causing tissue trauma, lumen occlusion, collapses if excessive suction
Describe a flat tube drain and its advantages and disadvantages
Flat tube drain - flattened cylinder, silicone rubber, fenestrations
Advantages - can apply suction
Disadvantages - rigid causing tissue trauma, lumen occlusion, collapses if excessive suction, expensive
How should the fenestrations in a tube drain be cut?
Obliquely
<1/3 of the tube diameter
Describe a sump drain and its advantages and disadvantages
SUmp drain - tube drain, 2 lumina, one for fluid evacuation, other for air evacuation
Advantages - vented suction, good for body cavities
Disadvantages - contamination (use bacterial filter), omentalisation
Describe a Sump-Penrose drain and its advantages and disadvantages
Sump-Penrose drain - Sump & Penrose, can have fenestrations, can have cause
Advantages - reduced blocking
Disadvantages - Contamination, inflammation with gauze, inefficient for intended use
Describe a modified Sump=Penrose drain and its advantages and disadvantages
Modified Sump-Penrose drain - Sump-penrose, tube drain as well
Advantages - wound irrigation
Disadvantages - contamination, don’t really need irrigation
How should the abdomen be drained?
Abdominal drain would be blocked with omentum
Open peritoneal drainage better
Part close the linea alba
What is the aim for suction during drainage?
Obliteration of dead space No damage to tissues No ingress of air No reflux of fluid into wound Air-tight closure of wound or vacuum lost
What are the three ways suction can be classified?
Connection with environment - closed or vented
Application of suction - continuous or intermittent
Suction generator - syringe, portable container, vacuum generatro
Describe closed suction and its advantages
Implants - negative pressure applied, single lumen drain
Advantages - wound and dressing kept dry, reduces incidence of seroma/haematoma, reduces bacterial ascension, reduces infection rate
Describe vented suction and its advantages and disadvantages
Implants - negative pressure applied by a continuous generator, double/multi lumen drain (egress wound fluid, ingress air)
Advantages - efficient for removing large volumes, reduces likelihood of drain collapse
Disadvantages - air passage may be traumatic, increased risk of ascending infection
What are the advnatages and disadvantages in using a rigid container for suction drainage?
Advantages - light, ready-charged, constant suction, high pressure, vacuum indicator
Disadvnatages - bulky, difficult to recharge, single use
Describe the difference between the two compressible containers for suction drainage
One is accordion like that is single use
Other is more balloon shape with multiple openings that can be used multiple times
What are the advantages and disadvantages of the accordion-like compressible container for suction drainage?
Advanatages - light, cheap, easy to recharge
Disadvantages - low pressure, single use, need to charge, may lose suction, no suction indicator, empty by disconnection
What are the advantages and disadvantages of the balloon like compressible container for suction drainage?
Advantages - light, easy to recharge, separate opening, multiple use, easy to attach
Disadvnatages - expensive, low rpessure, need to charge, may lose suction, no suction indicator
What are the advantages and disadvatnages to using a syringe in suction drainage?
Advantages - light, cheap, can recharge
Disadvantages - awkward shape, difficult to recharge, unknown pressure, no indicator, pin may fall out
What are the advnatages and disadvantages of using a vacutainer in suction drainage?
Advantages - light, easy to replace, cheap
Disadvantages - awkward shape, fragile glass, small volume, needle may fall out
What are the five general rules when placing drains?
Avoid enrves and blood vessels Avoid anastomotic sites Avoid contact with suture line Avoid drain when closing wound Anchor drain - within, at exit site
What are the six general rules concerning the exit hole of a drain?
Minimum number of holes Clip hair around exit hole Not through primary wound Not through flap base Exit dependently Exit hole of sufficient size
Describe placement of a drain at surgery
Tunnel from wound to exit hole
Penetrate skin at exit site
Passive - forceps and scalpel
Active - trochar
What are the indications for blindly placing a drain?
If wound not explored
If large cavity unexplored
If wound already closed
What is the technique for placing a drain blindly?
Stab incision
Forceps into wound cavity
Pass suture blindly close to forceps
Traction on drain confirms engagement
What are some common mistakes made when placing passive drains?
Exit wound too small SUbcutaneous tunnel too long Exit holes dependently and non-dependently Fenestrations Poorly clipped Drain not in wound Non-dependent exit
What are some common mistakes in placing tube drains?
Suction not continuously applied
Fenestrations outside wound
Left in place too long
What are the four aims of wound management?
Achieve a healed wound
Minimise scar formation
Preserve function
Prevent infection
What are the five steps of wound management?
Initial management Assessment of the patient Assessment of the wound Management of the open wound Closure of the wound
What should be done during initial management?
Cover wound - prevent further contamination, prtoect from trauma, helps achieve haemostasis
Pressure may be required - additional haemostasis
Additional support if fractures present - firm support bandage or splint, helps reduce pain, prevent soft tissue injury, reduce contamination of deeper tissue
Transport on flat surface if spinal injury suspected
May have to be muzzled
Gentle and sympathetic treatment
What should be the first thing that is established when assessing a patient?
Airways
Breathing
Circulation
What should be noted when assessing a patient?
General health Current medical problems Any medication being used Aetiology of wound Any treatment already been given BCS
What should be provided at the earliest opportunity to a wounded patient?
Appropriate analgesia
What is established when assessing a wound?
Aetiology
Nature
Location
Extent and degree of contamination
What should be assessed with wounds overlying the thorax and abdomen?
Integrity of pleural and peritoneal space
What should be ruled out on wounds on the limbs?
Damage to underlying bones, joints and neurovascular structures
What are all open traumatic wounds by definition?
Contaminated or dirty
What are most contaminants identified in wounds?
Hospital-acquired bacteria
What is needed when doing wound management?
Strict aseptic technique
What should be included in strict aseptic technique?
Use of sterile dressings Use of sterile instruments Aseptic preparation of the surgeon Management of the wound in theatre Management of the wound in prep room
What is the most useful sample that can be taking for predicting organisms that might cause wound infection?
Sample taken after debridement and lavage
What is the golden period in wound management?
Less than 6 hours after injury - wound may be cleaned out and closed primarily without development of infection
What other factors can influence infection development?
Bacterial numbers
Virulence
Wound factors
Inegrity of host response
When are antibiotics not needed?
When a healthy bed of granulation tissue has formed
What is the primary goal of all wound management?
Promote the development of a healthy vascular wound bed
Must be free of: necrotic tissue, debris,infection
What are the seven steps to promoting granulation tissue development?
Protect wound from desiccation and contamination
Preparation and clipping
Debridement of necrotic tissue
Removal of foreign material and contaminants - lavage
Provision of adequate wound drainage
Promotion of a viable vascular bed
Selection of the appropriate method of closure
How is a wound prevented from further wound contamination?
Covering with sterile dressing - saline-soaked gauze swabs
What should animals be for adequate wound preparation?
Sedated or anaesthetised
What may be used in conscious animals for wound preparation?
Local or regional anaesthetic techniques - local application, infiltration, ring block, regional block
What are the four steps of preparation and clipping?
Wound protection
Tissue handling
Clipping of hair
Surgical preparation
Describe wound protection
Protected with KY jelly or saline soaked swabs
Can be temporarily closed with sutures of towel clips
If very dirty animal may be bathed first
Describe tissue handling in prep and clipping
Atraumatically
Should not probe wound before prep
Should not replace bone fragments into the wound
Prepare to splint unstable limbs
Describe clipping of hair
Begin at wound margins and move outwards
Clip generous margin around the wound to allow exploration
Hair removed with vacuum
Use sharp, wet blades with moist hair
Describe surgical preparation of a wound
KY jelly or swabs are replaced to cover wound and skin
Prepare wound aseptically
Start at margin and move to periphery
Antiseptic kept out of wound
What is debridement?
Removal of necrotic tissue
What is the most common cause of delayed wound healing?
Inadequate debridement
How can debridement be achieved?
Scalpel - sharp debridement
Adherent dressings - wet to dry, dry to dry
Hydrogel dressings
Enzymes - trypsin, chymotrypsin
What is used most commonly for debridement?
Scalpel debridement
What should be avoided when debriding?
Use of diathermy
Ligating large pedicles
Excessive retraction or dissection
Describe debridement action with skin and subcutis
Excise liberally
Back to bleeding tissue
Preserve vessels
Describe debridement action with fat and fascia
Excise liberally
Describe debridement action with muscle
Excise until bleeds/contracts
Preserve function
Describe debridement action with tendon/ligament
Staged debridement
Preserve function
Anastomosis
Describe debridement action with nerves and vessels
Preserve if possible
Ligate damaged vessels
Describe debridement action with bone
Preserve if vascularised
Remove if unattached and small
Describe debridement action with joints
Lavage and remove small loose fragments
Close if possible
What is tissue viability assessed using?
Simple measurements - colour, warmth, pain sensation, bleeding
Complex measurements - Doppler ultrasound, transcutaneous pO2, fluorescein injection, scintigraphy
Describe layered debridement
Begin at wound margins and progress deeper into wound
Each layer considered separately
Allows selection in which tissue is removed
Not all necrotic tissue may be removed
What is en bloc debridement?
Complete excision of the wound
No entry into wound
Can be packed or closed with swabs first
Removes more tissue and results in a larger wound
May be damage to surrounding vital strutctures
What are the aims of lavage?
Remove foreign debris and contaminants
Keep tissue hydrated
Describe a simple and inexpensive wound lavage apparatus
18 gauge needle
Attached to 20 ml syringe
Bagof fluids via a giving set
Three way tap
Describe a wound lavage
Wound edges are gently elevated
Examine deeper fascial planes
Bacteriology swab may be taken
High volumelavage use tap water via shower head
Definitive lavage performed with sterile isotonic fluid
Daily after changing the dressing
What are the reasons for closing a wound?
Can convert to a clean wound No skin tension Wound is not a crush wound Wound is not infected Granulating wound Wound won't heal by 2nd intention
What are the reasons for not closing a wound?
Puncture wound
Can’t debride and lavage
Infected wound
Tension on closure
What are the four options for wound closure?
Primary closure
Delayed primary closure
Secondary closure
Second intention healing
Describe primary closure
Direct apposition of the skin edges
Performed for clean or clean-contaminated wounds
Restores normal function promptly
Requires general anaesthesia
Leads to problems if used inappropriately
Describe delayed primary closure
Apposition of the skin edges performed 2-5 days after wounding
Cover with sterile dressing for time before closure
Decreases the incidence of wound infection
Used when wound contamination can’t be romeved
Complications may still arise if used inappropriately
Describe secondary closure
Wound closure in presence of granulation tissue
Combined with reconstructive techniques to avoid excessive wound tension
Indicated for wounds with superficial contamination or invasive infection
Performed 5-10 days after wounding
Comprises either: direct appostion of granular surfaces, excision of granulation tissue and primary closure
Excision of granulation tissue may reduce infection incidence but is more time consuming and traumatic
Rapid wound healing
Delayin wound closure
Reduction in tissue pliability
Describe second intention healing
Healing by contraction and epithelialisation
Normally successful in small animals
Reserved for dirty wounds when the other techniques aren’t possible
Likelihood may be determined by assessing laxity in adjacent skin
Any defects left once wound edges have moved will heal by epithelialisation
What are the disadvantages of secondary intention healing?
Expensive if many bandage changes, hospital vists and medication are required
Healing is prolonged
Healing may not progress to completion and chronic non-healing wound may result
Cosmetic result is fairly poor
Recurrent wound breakdown may occur
Stenosis or impairment of function may occur
Reduction in limb movement may occur
What are the three types of wound?
Elective incisional
Elective excisional
Traumatic
What is the method of wound closure determined by?
Patient's physical status Degree of wound contamination Amount of soft tissue damage Vascularity of the tissues Amount of adjacent tissue available for closure
What are the aims of wound reconstruction?
Complete and durable wound closure Wound healing inthe shortest possible time Minimal patient discomfort Minimal patient morbidity Cosmetic appearance
What should be looked at when planning wound reconstruction?
Evaulation of inherent elasticity of local skin
Identification of skin tension lines and likely effect
Position and importance of local strutcures
Location of adjacent direct cutaneous arteries
Previous surgical or traumatic wounds in the region
Evaluation fo viability and vascularity of local skin
Describe the surgical techinque menu
Closure of edges - primary closure, delayed primary closure
Mobilisation of local skin - suture techniques, skin-stretching
Mobilisation of adjacent skin - subdermal plexus flaps, axial pattern flaps
Mobilisation of distant skin - distant direct flaps, distant indirect flaps
Use of free skin grafs - partial thickness graft, full thickness graft
Second intention healing - contraction and epithelialisation
Describe the tension-relieving techinque menu
Maximise available skin - patient positioning
Change local skin tension - geometric closure patterns
Change regional skin tension - skin directing
Mobilise local skin - undermine skin
Increase local skin - skin stretching
Dsitribute tension - walking sutures
Overcome tension - tension sutures and stents
Remove tension - relaxing incisions
What is one of the most importnat factors inachieving a closed wound which will heal?
Management of tension in the wound edges
What can wounds closed with excessive tension suffer from?
Compromised circulation
Slow wound healing
Dehiscence
Distortion of anatomic areas
What are the effects of tension on closure of skin wounds?
Wounds made parallel to tension lines will close with minimal tension
WOunds made perpendicular to tension lines will gape with greater tension
Wounds at an oblique angle will form a rhomboid wound
How can patient positioning maximise available skin?
Towels, sandbags or bead-filled vacuum bags
Placed under sternum and pelvis or shoulders
Loose skin can be pulled towards surgical site
How should wounds be closed wherever possible?
Linear or curvilinear fashion
Describe local closure of small defects with a fusiform exicision
Long axis orientated parallel to woud tension lines
Length:width ratio of 4:1 recommended to avoid creating dog ears
Describe management of dog ears
Triangular, raised skin ears following wound closure
Number of techniques to remove
May be left and will flatten over 6-8 weeks
What three shapes can be used for local closure of small defects?
Triangle - 3 point closure for Y-shaped wound
Square - centripetal closure for X-shbaped wound
Rectangle - centripetal closure for double Y-shaped owund
How can local tension be relieved?
V-Y plasty
Z-plasty
What is the aim of skin directing?
Use available skin in the most optimal way to achieve maximum wound coverage
What is the simplest techinque for relieving wound tension?
Undermining skin edges
Describe undermining skin edges
Relieved from underlying attachments
Allows inherent elastic properties to be used
Avoid trauma to subdermal plexus and cutaneous arteries
Proceed until wound edges approximate without excessive tension
What are the correct planes for undermining skin?
Cutaneous muscle present - undemrine below muscle
Cutaneous muscle no present - undermine in loose fascia below
SKin associated with muscle - undermine below muscle fascia
Describe skin stretching pre-suturing
Vertical mattress tension sutures used to imbricate normal skin
Placed under sedation and local anaesthetic
Removed after a period of time and lesion excised
Extra skin can be used to achieve wound closure
Simple and cheap
Requires 2 procedures
Pull on adjacent skin is focal and non-adjustable
Describe skin stretching using skin stretchers
Externally applied, non-invasive, adjustable devices
Stretch skin adjacent and distant to wound
More significant gains than pre-suturing
Cables help hold dressing in contact with wound
Describe skin stretching with skin expanders
Silicone elastomer bag
Connected to a tube to a self-sealing, implantable injectin port
Buried in a pocket below skin to be stretched
Injection port bured in adjacent tissue
Periodic inflation of expander by injecting sterile saline
Describe tension-relieving incisions
Incision created parallel to long axis of a wound
Facilitates closure
May be: single, double and multiple
Generally left to heal by second intention
Describe relaxing incisions for primary closure
Incision placed adjacent and parallel to primary wound
Allow intervening skin to close defect
Indicated when it will allow primary closure of main wound
Describe multiple relaxing incisions
Multiple small stab incisions made instaggered rows parallel to primary wound
Release tension in skin adjacent to the wound
Allow primary wound to be closed
Stab incisions left to heal by second intention
Indicated for closure of wounds on extremeties
Describe relaxing incisions for skin flaps
Incision in flap or adjacent tissue
Incisions in adjacent skin are preferred
Avoid regional direct cutaneous artery
What are the four local flaps?
Advancement flaps
Transposition flaps
Rotation flaps
Flank fold flaps
Describe advancement flaps
Limited to areas with loose skin
Developed so they advance parallel to lines of skin tension
Skin tension may promote wound dehiscence or distort wound
Describe transposition flaps
Rectangular flap created with 90 degrees of long axis of defect
One long edge of flap shared by defect
Loss of flap length
Increased likelihood of dog-ear development
Describe rotating flaps
Arc of skin which shares a common border with a triangular defect
No secondary donor site defect is created
Skin provided by combination of stretching and moving adjacent skin
No advantage over transpositional
Useful for local closure of triangular defects
Length required is 4 times length required to rotate the flap to cover defect
