Infection and Debridement

Factors affecting the immune system

Pregnancy

Pre-existing infections

Cancer/surgery/malnutrition

Surgery (anesthesia suppresses T and B cell function)

Age

Immunosuppressed

Indwelling lines and tubes

Chronic disease (DM, CVD)

How does DM affect the immune system

Neuropathy impairs pain perception

Phagocytosis impaired with hyperglycemia

How does CVD affect the immune system

Pathogens thrive in areas with low perfusion (delivery of antimicrobial agents is dependent on circulatory system)

Defenses against infection

Microflora (in skin and GI)

Acidic pH of skin

Immune cells and inflammatory response

Complement system

Factors that increase the risk of infection

Host: skin integrity, DM, malnutrition, high BMI, steroids, age, immunocompromised

Local: ischemia, necrosis, wound debris, chronic wounds

Signs and symptoms of infection

Redness: poorly defined erythemal border, disproportionate amount, proximally directed streaking

Temperature: large localized increase, febrile

Edema: disproportionate, periwound indurated

Pain: increased/new onset, disproportionate

Function: malaise, tachycardia, hypotension, altered mental status

Drainage: thick/purulent/creamy, white/green/blue, odor, disproportionate

Decline in wound: decreased amount of granulation, friable, cobblestone like, color change

Signs of inflammation but excessive and disproportionate

Biofilms

Microorganisms attached to wound surface which protects against environment, antiseptics, and microbials but increases bacterial virulence and resistance

Bacteria identification

Unicellular, rigid cell wall, no nuclear membrane, reproduce by cellular division, require external medium for growth

Staining

Gram positive cocci (purple circles): staph aureus → skin infection, toxic shock

Gram negative cocci (pink circles): gonorrhea

Gram positive bacilli (purple rods): anthrax → pneumonia

Gram negative bacilli (pink rods): E coli → UTI

Antimicrobial therapy

Antimicrobial agents destroy unicellular organisms

Antibacterials (cidal = kill) (static = inhibits growth)

What does premature cessation of antimicrobials do?

Increases antibiotic resistance to microbes

MRSA causes

Nosocomial (age, DM, immunosuppressed, malnutrition, immobility, burns)

Community acquired (prisons, contact sports, military)

Can cause cellulitis, osteomyelitis, abcess

VRE

found in GI or female reproductive tract and treated with vancomycin

Most common fungal infections

Tinea and candida of skin and nails

Increased risk through antibiotics, DM, moist occluded skin

Antimicrobial Topical Treatments

Low cost, reduce bacterial load, effective when circulation is compromised

Requires frequent application, sensitivity/allergic rx, potential for resistance

Only used when infection is present

Antiseptic agents

Prevent infection by killing microorganisms (cytotoxic, slow wound healing, increase duration and intensity of inflammatory process)

Systemic antimicrobial therapy

Sepsis, advancing infections, with/without topicals

Reduces bacterial load and has better adherence

Adverse reactions, resistance, missed doses and higher cost

Clean vs sterile

Clean: reduce number of microorganisms present to decrease risk of transmission

Sterile: only sterile equipment contacts patient’s wound (packing wounds, large SA, severe burns, immunocompromised)

Debridement

Remove debris to increase rate of healing (non-viable tissue impairs healthy granulation and migration of keratinocytes) (necrotic tissue serves as medium for bacterial growth) (decreases energy use for wound healing)

Indications for debridement

Necrotic, foreign material, debris

Blisters and callus

Residual topical agents

CI for debridement

Red, granular wounds

Heel ulcers with eschar if they do not have edema, erythema, fluctuance, drainage

Electrical burns prior to physician assessment

Pyoderma gangrenosum

Pyoderma gangrenosum

Ulcerating skin disease with well defined borders that are violet or blue; surrounding skin is erythematous and indurated

Small papule or collection which break down into small ulcers with “cat’s paw” appearance

Associated with bowel disease, arthritis, leukemia

Methods of debridement

Selective: sharp, autolytic, enzymatic, biological

Nonselective: surgical and mechanical

Sharp debridement

Use of forceps, scissors, curettes, scalpel (most aggressive) (rapid results, pain, bleeding, highly selective), debride in layers and parallel to surface and rinse with saline

Indications: large amounts of necrosis, callus, cellulitis, sepsis, eschar; chronic wounds

CI: cannot visualize, lack of clinician competency, infected ischemic ulcers with low ABIs, immunosuppressed, thrombocytopenic, hypergranular tissue, hands/face

Autolytic debridement

Endogenous enzymes digest necrosis with moisture-retentive dressing (least invasive and least painful) - requires time to occur and cannot visualize wound (stop if necrosis fails to decrease in time) (cross hatch eschar and apply dressing for 72-96 hours)

Indications: all wounds with necrosis, pt who cannot tolerate

CI: infected or deep cavity wounds, wounds that require sharp/surgical

Enzymatic debridement

Uses collagenase (stop if necrotic tissue fails to decrease or when successful and requires rx)

Indications: infected/uninfected wounds with necrosis; cannot tolerate sharp

CI: wounds with exposed deep tissues, facial burns, callus, no necrosis, autolytic debridement

Mechanical debridement

Use of force to remove devitalized tissues/foreign/debris (wet-to-dry dressing, scrubbing, irrigation, lavage, whirlpool)

Wet to dry dressings

Only used for wounds with 100% devitalized wound bed

Scrubbing

High porosity sponge, brush, gauze with water or saline

Indication: highly contaminated superficial wounds

CI for granulating wounds

Pulsatile lavage with suction

Reduces bacterial count and promotes granulation formation through negative pressure (can be used for cleaning and debriding)

For wounds with >50% necrotic tissue with purulent drainage/foul odor twice a day; less for healthy tissue

Biological debridement

Larva therapy (maggots consume only necrotic tissue) - rapid, painless, deep and tunneled wounds; faster than autolytic and enzymatic

Can decrease odor and exudate, increase granulation and epithelialization

Surgical debridement

Allows for extensive exploration of wound bed using scalpels, scissors, lasers in sterile environment

Indications: ascending cellulitis, osteomyelitis, extensive necrotic wounds, undermining or near vital organs

CI: unlikely to survive or palliative care plans

Burn wound care

Mild soap, warm water, washcloth, norsen debrider