Wound Management

What are the 3 phases of wound healing?

Inflammation

Proliferation

Remodeling and Maturation

What are the goals of the inflammatory phase of wound healing?

Stop bleeding

Initiate wound healing cascade

Remove wound contaminants and damaged tissues

How long is the inflammatory phase of wound healing?

0-4 days

What are the components of the inflammatory phase of wound healing?

Platelets

Neutrophils

Macrophages

What do activated platelets release?

Cytokiens

What was vasodilation and increased vascular inflammatory cause in the inflammatory phase?

Heat, redness, and swelling

What activates neutrophils?

Cytokines

When are neutrophils present?

1-48 hours of a wound

What do neutrophils do?

Kill bacteria (need oxygen)

Break down ECM

Phagocytosis of debris

Release more cytokines

T/F if neutrophils are present, then a wound has to be infected?

False

What is required for neutrophils to kill bacteria?

Oxygen

When are monocytes most common in a wound?

96 hours

What do monocytes do?

Coordinate ongoing wound healing including proliferative phase

Phagocytosis and degradation of ECM

What are macrophages essential for?

Release of further signaling molecules and wound healing

How long is the proliferation phase of wound healing?

Day 4-12

What are the goals of the proliferation phase of wound healing?

Restore blood flow

Replace lost tissue

Achieve wound closure

What are the components of the proliferation phase of wound healing?

Fibroblasts

Myofibroblasts

Endothelial cells

Epithelial cells

When are blood vessels, collagen matrix, and epithelial coverage be reconstructed?

Proliferation phase

When does angiogenesis occur?

Proliferation phase

What signals for angiogenesis to begin?

Hypoxia

What will prevent angiogenesis from occuring?

An area with complete absence of oxygen

When does angiogenesis typically occur?

4-6 days post injury

What cell does fibroplasia?

Fibroblasts

What do fibroblasts produce?

Collagen and ECM

Describe type III collagen

Appears 4-5 days after wound (granulation tissue)

Describe type 1 collagen

Peak synthesis 7-14 days after wounding

Describe granulation tissue

Angiogenesis and fibroplasia together that will fill an entire wound bed

What does granulation tissue consist of?

Capillary bed, fibroblasts, macrophages, and ground substance matrix

When do myofibroblasts form?

After granulation tissue develops (day 6 to week 6)

What do myofibroblasts do?

Pull wound edges together

When does contraction of the proliferation phase stop?

Until epithelial surfaces meet or tension exceeds strength of myofibroblasts

What organizes the contraction part of the proliferation phase?

Myofibroblasts

When does epithelization start?

Within hours of wounding

How much epithelization occurs a day?

1mm

When does epithelization stop?

When edges of wound meet

What are the advantages of contraction?

Full thickness skin covers the area

Skin will have hair and glands

What are the disadvantages of contraction?

Too much can impair function

Called contracture

What are the advantages of epithelialization?

Better for high tension areas

What are the disadvantages of epithelialization?

Skin is more fragile and non-haired

Takes longer than contraction

When does remodeling and maturation occur during wound healing?

Day 12 - Day 500

What happens during remodeling and maturation?

Replacement of type III collagen with type 1 collagen

Increased strength of tissues

Collagen redistributed to areas of stress

Collagen synthesis decreases

What are the 2 instances where the tissue returns to original strength?

Urinary bladder

Bone

T/F rate of healing varies by tissue?

True

What are the goals of open wound management?

Provide ideal environment

Decrease contamination

Protect wound as it transitions

Cultivate periwound

What are the steps of wound management?

Triage

Clip

Lavage/Cleanse

Debridement

Decide

Dress

Close

T/F you should clip wide margins around the wound?

True

What should you lavage with?

Isotonic cystalloids

How can lavage be delivered?

Syringe and catheter tip

Pulsatile lavage unit

IV fluid bag and extension set

Shower attachment to sink

How long should you lavage?

5-10 minutes

What happens during cleansing?

Clean the peri-wound skin with antiseptic solutions

Why do we precent chlorhexidine gluconate or povidone iodine from getting into the wound during cleansing?

It is toxic to fibroblasts

Whare do we use for cleansing?

Chlorhexidine gluconate 0.05%

Povidone iodine 0.1%

What do we not clean the wound with?

Hydrogen peroxide

Concentrated antiseptics

Alcohol

What id debridement?

Removal of devitalized tissue and foreign debris

When do you treat a wound as sterile?

After cleansing during debridement

How do you start debridement?

Surgical debridement

How can you manage a wound?

Primary closure

Delayed primary closure

Allow to heal by contraction and epithelialization (second intention healing)

Secondary closure (third intention healing)

What is primary closure?

Immediately close a wound

What is delayed primary closure?

Closure within 3-5 days of wounding (before granulation)

What is allowing to heal by contraction and epithelialization (second intention)?

Leave it open

What is secondary closure (third intention healing)?

Closure after establishment of granulation tissue bed

What are factors that influence wound management?

Client factors

Wound factors

Patient factors

What is the golden period of wound repair?

6 hours after (amount of time for a single bacteria to replicate into 10^5 bacteria per gram of tissue)

What is the number of bacteria required to cause infection?

10^5 bacteria per gram of tissue

Why will just bacteria not negatively impact wound healing?

It needs to be enough bacteria to cause an infection

What is a clean wound?

Operative incisions not entering the respiratory, GI, genitourinary, or oropharyngeal tracts

What wounds are always created by a surgeon?

Clean

Clean-contaminated

What is a clean-contaminated wound?

Operative incision entering the respiratory, GI, genitourinary, or oropharyngeal tracts

Clean surgery where a drain is placed

What is a contaminated wound?

Operative incision with a major break in asepsis or spillage of GI contents or infected urine

Non-operative wounds with no necrosis or purulent discharge

What are dirty wounds?

Operative incisions with fecal contamination or a previously perforated viscus

Non-operative wound with necrosis, purulent discharge, or foreign material

When do you use primary closure?

Clean or clean-contaminated

Contaminated wounds converted to clean

You can close it with minimal tension or able to use tension relieving technique

When is primary closure ideal?

High motion areas or animals with systemic impediments to healing

When should you not use primary closure?

Contaminated or dirty wound

Infected

Lots of tension/not enough skin

Potential for further tissue necrosis

Patient not stable

When in doubt about closing

What are the 3 layers of dressing a wound?

Primary (contact) layer

Intermediate (secondary) layer (not always used)

Outer (tertiary) layer (not always used)

The choice of a primary layer should be based on?

Amount of drainage

Presence of necrosis

Stage of wound healing

Management plan

What are the functions of the intermediate layer of a bandage?

Absorption of wound exudate

Support and immobilization

Uniform compression

What is an example of an intermediate layer?

Cast padding or roll cotton outer layer of roll gauze

What are the functions of the outer layer of a bandage?

Protects from environment

Hold bandage in place

Additional compression

What is an example of outer later of a bandage?

Porous surgical tape, elastic self-adherent material (VetWrap), stockinette

What is the strength of skin after it heals?

80%

What is the time to max healing of skin?

3 months

What is the wound strength of an healed colon?

53%

What is the time to max healing of the colon?

28 days

What is the max wound strength of the stomach?

70%

What is the time to max healing of the stomach?

21 days

What is the max strength of healing for the urinary bladder?

100%

What is the time to max healing for the urinary bladder?

21 days

What is the max wound strength of the fascia?

80%

What is the time to max healing of the fascia?

6 months

What do drains not replace?

Proper debridement/lavage/cleansing

When should you use drains?

Large pocket that cannot be closed adequately

Pocket is ventral from a wound

Ongoing fluid production is expected in an where where it will lead to compromise

What technique do you need to handle drains?

Clean

How do passive drains work?

Drainage occur via capillary action along the outside of a drain tube

Dependent on gravity for drainage

What is the most common passive drain?

Penrose drain

How do active suction drains work?

Tube is attached to a suction canister

Fenestrated area is entirely within wound

Cover exit site with bandage

How force allows for active suction drains to work?

Vacuum effect and not gravity

T/F active suction drains are more versatile but rely on an air-tight seal of primary wound?

True

What is the benefit of a reservoir for an active suction drain?

Quantification of fluid

What is drain removal based on?

Fluid quantity and quality

What color should fluid from a drain be before changing?

Serosanguinous