Healing, Infections, and Biophysical Agents

What are the key factors in signaling?

• Chemical signals

• Chemical stability

• Scaffold binding

• Cell receptors

• Chemical properties

• Cell interactions

What are the key cells involved in healing?

• Macrophages

• Platelets

• Fibroblasts

What are senescent cells?

Cells that are couch potatoes and don’t do their jobs

Do senescent cells help in acute or chronic wounds?

Acute, they inhibit wound closure in chronic setting

What are the different healing response mechanisms?

• Continuous cell cycling (liable cells proliferating and undergoing apoptosis)

• Cell proliferation (damaged tissue replaced which doesn’t fully duplicate structure but approximates function)

• Regeneration (structure and function of lost tissue is fully restored)

• Fibroproliferative response/healing (patching lost tissue to restore skin covering, integrity, and function)

What are the stages of acute wound healing?

1. Hemostasis (stop the bleeding)

2. Inflammation (defense and cleanup)

3. Proliferation (repair damage)

4. Maturation (strengthening repair)

Describe the wound healing phase: hemostasis

• Vasoconstriction of the injured vessel and vasodilation of the adjoining vasculature

• Platelets and fibrin form a stable clot

• Polymorphonuclear (PMN) and macrophages get together to kill and contain pathogenic invaders

Describe the wound healing phase: Inflammation

• Immune system responds

• Macrophages do some debridement

• Neo-angiogenesis to start granulation

Describe the wound healing phase: Proliferation

• Angiogenesis

• Fibroplasia

• Matrix deposition

• Epithelialization

Describe the wound healing phase: Maturation

• Wound remodeling

• Dermal regeneration

• Wound contraction

• Programmed shrinkage of granulation tissue

An acute wound will heal within how many days?

21

What effect do steroids have on healing?

• Delay inflammatory response and fibroblast activity

• Reduce collagen deposition and angiogenesis

• Decrease wound contraction and epithelial

What are some things that we worry about clinically when someone is on steroids?

• Ulcer recurrence

• Thin, fragile skin that is prone to tears and bruising

What impacts do NSAIDs have on healing?

• Decreased platelet aggregation and increased bleeding risk

• Reduced hyaluronic acid and collagen synthesis

• Delayed inflammation and resolution and granulation tissue formation

What are some things that we worry about clinically when someone is on NSAIDs?

• Poor-quality granulation tissue

• Increased infection risk

• Difficulty in going from inflammation to proliferation phases of healing

What impact do anticoagulants have on healing?

• Inhibition of fibrin deposition and delayed healing

• Increased bleeding and wound complications

What are some things we are worried about clinically when someone is on an anticoagulant?

• Hematomas, ecchymoses, and potential skin necrosis

• Complications in post-op wound healing

What impact do antirejection medications have on healing?

• IMpaired immune response and healing

• Decreased lymphocyte, monocyte, and basophil counts

• INCreased risk of infection and poor nutritional state

What clinical signs do we see when someone is on antirejection meds?

• Frequent wound dehiscence

• Poor quality granulation tissue and epithelial bridging

• Risk of drug-induced diabetes and squamous cell carcinoma

What impact does diabetes have on healing?

• Prolonged inflammatory phase

• Impaired proliferative phase

• Impaired angiogenesis and maturation

What are some signs that a wound is non-healing in diabetics?

• Heavy callus formation

• Chronic inflammation

• Frequent infections

• Slow or no healing progress

What impacts does obesity have on healing?

• Adipose tissue releases fatty acids, hormones, and pro-inflammatory cytokines

How does malnutrition impact wound healing?

Makes it so we don’t have enough protein for wound healing

How does arterial insufficiency impact healing?

Reduces oxygen and nutrient delivery

How does CVI impact healing?

• Blood pooling

• Capillary damage

• Fibrin accumulation

• Growth factor entrapment

How do cardiac diseases impact wound healing?

• Accumulation of senescent cells

• Elevated pro inflammatory stressors

• Poor tissue repair

• Fibrosis

What condition is known to be an independent predictor of delayed or reduced wound healing?

Comorbid HF

How does chemotherapy impact wound healing?

• Interferes with cell division

• Anemia, neutropenia, and thrombocytopenia

• Delays wound healing via inhibiting protein synthesis, angiogenesis, and ECM formulation

How does aging impact healing?

• Slower inflammatory response

• More platelet clumping

• Delayed immune cell activity

• Less growth factor production

• Slower skin cell renewal

• Reduced blood vessel growth and collagen formation

• Weaker tissue strength

How can we reduce the effects aging has on healing?

Exercise! It induces an anti-inflammatory response in wounds

How does stress impact healing?

• Releases pro inflammatory cytokines that delay initial healing

• Causes release of catecholamines which reduces blood flow and causes a weaker cell response which leads to fewer fibroblasts and poor tissue formation

What is biofilm?

A thick, polysaccharide capsule that pathogens use to prevent immediate destruction by the host that is a thin, adhered yellow layer on the wound

How do we get rid of biofilms?

• Sharp debridement with low frequency US or an iodine-based topical dressing

Bacteria in a wound can be divided into 4 categories, what are they?

• Contamination

• Colonization

• Critical colonization

• Wound infection

What is colonization? Is it normal? What effect does it have on wounds?

• The presence of bacteria on a wound surface

• Normal to happen

• No effect on wounds

What is contamination? Is it normal? What effect can it have on wounds?

• The presence of replicating microorganisms on a wound surface

• Normal for wounds

• No abnormal effects

What is critical colonization? Is it normal? What effect can it have on wounds?

• An increase in wound bioburden that reaches a critical point and begins to adversely affect the host

• Abnormal

• Get a plateau in wound healing or a decline in wound status

What is an infection? Is it normal? What effect does it have on a wound?

• Replicating microbes that invade viable body tissues

• Abnormal

• Decline in wound status and S/S of infection

What are the S/S of critical colonization and infection? How many S/S need to be present for it to be considered critical colonization? What about an infection?

• S/S

  • Delayed healing

  • Abnormal order

  • Friable granulation tissue (aka it bleeds easily)

  • Increases serous exudate

  • Change in color of the wound bed

  • Absent or abnormal granulation tissue

  • Increase pain at the wound site

• 1-2 of these S/S for critical colonization

• 3+ = infection

What is the most common infection control practice?

Aseptic technique

Describe the aseptic technique for infection control practice

Purposeful prevention of the transfer of microbes by keep an area as free from contamination as possible

Give some examples of topical antiseptics

• Betadine

• Dakins solution - bleach

• Acetic acid - vinegar

• Hydrogen peroxide

Give some examples of some microorganisms that are resistant to antibiotics

• VRE

• MRSA

Give some examples of topical antibiotics

• Bactroban

• Polymyxin

• Bacitracin

Give some examples of oral IV antibiotics

• Zyvox

• Vancomycin

• Sulfoamides

What is the gold standard for obtaining a culture? What can we do as PTs to get a culture?

• Gold standard: tissue biopsy

• What we do: tissue removal, aspiration, swab

Describe the Levine technique

Rotation of a swab over a 1cm² area of the wound with sufficient pressure to express fluid from within the wound tissue

Why do we use pulsed lavage with suction (PLWS) for wounds?

Negative pressure of the suction stimulates granulation of clean wounds

What is PLWS used for?

• Stalled granulation tissue tissue

• Presence of infection or necrotic tissue

• Presence of thick exudate Change

• Presence of undermining and tunnels

• Open amputation sites

• Traumatic wounds with debris

• Stage III and IV pressure ulcers

What are the benefits of PLWS?

• Enhanced wound cleansing

• Debridement of slough and loosens dead tissue

• Reduction of surface bacteria

• Increases blood flow and stimulates new tissue growth

What are the precautions for PLWS?

• When pt is on anticoagulants or active bleeding

• Poorly visualized wound spaces that may connect to body cavities (tracts, tunnels)

• When doing it near a fistula or cavity lining

• When near visible blood vessels

• When doing it over exposed bone or tendon

• When doing it near bypass grafts or recent surgical closures

• When near facial wounds

• Near LVAD drive lines

• Hypothermia with cool fluid irrigation

What pressure for PLWS is the safe application range?

4-15 psi

What psi should you use for PLWS for a sensitive area?

4-6 psi

What psi should you use for PLWS for A decrease in bacterial load?

8-9 psi

What psi should you use for PLWS for A noninfected wound to remove debris?

9-15

How much pressure should be used for PLWS for continuous suction?

60-100 mmHg

What pressure should you use for PLWS for a wound that is painful and/or bleeding?

60-80 mmHg

What pressure should you use for PLWS for The removal of exudate and necrosis?

80-100 mmHg

What is a normal saline irrigation temperature for PLWS?

37-38°C

How frequently should PLWS be done for infected, heavily draining wounds?

Daily

How frequently should you be doing PLWS for outpatients with moderate-to-heavy draining and signs of critical colonization?

2-3x/wk

How frequently should you be doing PLWS for outpatients with minimal drainage and no infection?

1x/wk

The transport of bacteria can be as far as ___ ft away from the tx area when doing PLWS

8 ft

What are the infection control guidelines when doing PLWS?

• Single pt room with non-fabric walls

• No open shelves in treatment area

• Only essential equipment in the treatment area

• Cover horizontal surfaces

• Place a mask on the pt

• Only essential personnel in treatment room, no family

• Cover all pt lines, ports, or other wounds

• Cover pt’s personal items

• Disinfect all surfaces touched in the tx area Cover

• Wear PPE (waterproof gown, gloves, face mask with splash shield or mask with goggles, hair cover, shoe covers)

• Don’t reuse single-use items

• Discard canister with contaminated fluid in biohazard

If treating multiple areas with PLWS during the same treatment area, where do you start?

In the cleanest area

How does electrical stimulation (ES) promote wound healing?

• Creates changes in…

  • Epidermal polarity

  • Cellular migration and function

  • Blood flow

  • Edema

  • Wound contraction

  • Decreasing bioburden

  • Improving autolysis

ES can increase wound healing by as much as __% per week

22%

What are the indications for ES?

• Pressure ulcers

• Arterial ulcers

• Venous ulcers

• Clean wounds with decreased or stalled healing

• Diabetic foot ulcers

What are the precautions for using ES?

• Using it with children under 3

• Skin irritation or burns under the electrodes

• Use in areas of impaired or absent sensation

• Skin irritation/burns from ion shifts

What are the contraindications for ES?

• Over known malignancy

• Osteomyelitis

• Over metal or topical agents containing heavy metal ions

• Electronic implant

• Upper/anterior chest (over heart)

• Near a developing fetus

• Over areas of active bleeding

• Position such that current would flow through the anterior neck or upper chest

• Trans-cerebral application

How does ES exactly work?

Attracts cells that are needed for wound healing into the wounded tissue via chemotaxis (attraction of cells toward a chemical) and electrotaxis (attraction of cells toward an electrical field or charge)

When healing phase will ya see platelets working?

Hemostasis and inflammatory

Are platelets attracted to the cathode (-) or anode (+)?

Cathode

What healing phase will you see macrophages?

Inflammatory

What healing phase will you see Neutrophils?

Inflammatory

What healing phase will you see Mast cells?

Inflammatory

What healing phase will you see Fibroblasts?

Proliferative

What healing phase will you see Epidermal cells?

Epithelialization/remodeling

What cell charge do macrophages have?

Negative

What cell charge do active Neutrophils have?

Positive

What cell charge do Inactive neutrophils have?

Negative

What cell charge do Mast cells have?

Negative

What cell charge do Fibroblasts have?

Positive

What cell charge do Epidermal cells have?

Negative

Are macrophages attracted to cathodes or anodes?

Anode

Are active neutrophils attracted to cathodes or anodes?

Cathode

Are inactive neutrophils attracted to cathodes or anodes?

Anode

Are mast cells attracted to cathodes or anodes?

Anode

Are fibroblasts attracted to cathodes or anodes?

Cathodes

Are epidermal cells attracted to cathodes or anodes?

Anodes

The deeper the wound, the ____ the placement should be between the treatment electrode and dispersive electrode

Farther

When benefits has negative pressure wound therapy (NPWT) shown to have for wound healing?

• Promotion of moist wound healing

• Reduction of edema and interstitial fluid

• Increased local perfusion

• Approximation fo wound edges

• Stimulation of granulation tissue formation

• Reduction in bacterial load

• Reduction in the frequency of dressing changes

How long after starting NPWT do you reassess for signs of healing?

2 wks

What is the average length of tx for NPWT?

4-6 wks

When doing NPWT, how frequently should you check to make sure ya got a good seal and no bleeding?

Every 2 hours

NPWT should be changes every ___ hours for a healthy wound and every ___ to ___ hours for an infected wound

• 48 hrs for a clean wound

• 12-24 hrs for an infected wound

What are the indications for NPWT?

• Acute and chronic wounds

• Acute traumatic and surgical wounds

• Burns

• Skin grafts

• Chronic venous insufficiency wounds

• Chronic diabetic wounds

• Chronic pressure wounds

• Arterial insufficiency wounds (with caution)

• Palliative care

What are the precautions for NPWT?

• When pt is on anticoagulants or has a low platelet count

• Fistulas

• When over bone, tendon, organs, or vessels

• When doing it with a kiddo

What are the contraindications for NPWT?

• Wounds with more than 30% slough, necrotic tissue

• Untreated osteomyelitis or wound infection

• Malignancy expect in cases of palliative care

• Directly over exposed vessels, bypass grafts, organs

• Ischemic outwards with significant proximal occlusion

• Intermittent none used over grafting

• Shows a negative response to initial treatment

How frequently should NPWT be changed?

Every 48-72 hours