Infection control, tissue integrity & specimen collection

The chain of infection

The host can then become the next reservoir, so the chain loops.

What makes a host more susceptible

Age; underlying disease (HIV/AIDS [human immunodeficiency virus / acquired immunodeficiency syndrome], malignancy, transplant); immunosuppressants, antirejection meds, antineoplastics, antimicrobials, corticosteroids, PPIs (proton pump inhibitors); surgery; radiation; indwelling devices (endotracheal [ET] tubes, urinary and central catheters, pacemakers, artificial joints).

Colonized means the organism lives in the body without causing problems. A colonized person can still be a reservoir and spread it. Virulence is how good an organism is at making people sick.

Modes of transmission

Body defenses

Protecting the skin barrier: gentle cleansers, moisturizers, less tape, no irritants. Detergents strip the stratum corneum (about half back in 6 hr, fully back in 5–6 days).

Passive immunity comes from an outside source (maternal antibodies, immunoglobulin) and is temporary. Active immunity is made by the body after exposure and lasts.

Inflammation

The 4 steps

What happens at a wound

Meds: antihistamines (diphenhydramine) block histamine and prevent swelling; NSAIDs (nonsteroidal anti-inflammatory drugs, such as ibuprofen) reduce painful inflammation. Acute inflammation is one event; chronic repeats (asthma, gastroesophageal reflux disease [GERD]) and can lead to tissue destruction and cancer.

Stages and types of infection

1. Incubation: exposure to first symptom. No symptoms, but labs may show changes. Seconds to weeks, depending on the agent.
2. Prodromal: vague symptoms: fever, aches, poor appetite, malaise.
3. Acute illness: disease-specific symptoms are obvious; infection is severe.
4. Decline: symptoms ease; strength returns.
5. Convalescence: back to the old or a new balanced state of health; may have lasting effects.

Chills (shivering) happen as a fever is starting: the body shivers to make heat and push its temperature up. Diaphoresis (sweating) happens as a fever is breaking: the body sweats to cool back down.

Sepsis: a systemic inflammatory response to serious infection that can cause organ failure and shock. Blood cultures confirm it. Highest risk: very young, very old, weak immune system, severe trauma.

Shingles (herpes zoster): reactivated varicella. Painful one-sided vesicular rash along a dermatome. Isolate until the vesicles crust over; keep away from infants, pregnant people who haven't had chickenpox, and immunocompromised clients. Acyclovir works best early. The two-dose recombinant vaccine prevents it but doesn't treat it. Pain lasting over 3 months after the rash is postherpetic neuralgia.

Diagnostic tests

WBC (white blood cell) count: 5,000–10,000/mm³. Above 10,000 (leukocytosis) = inflammation or infection. Below range = can't fight infection well (neutropenia).

• ESR (erythrocyte sedimentation rate): nonspecific; expected 15–20 mm/hr, above 20 = active inflammation. Varies by age and sex.
• CRP (C-reactive protein) and procalcitonin: nonspecific inflammation markers. Not standardized, so use the same lab for repeat draws.
• UA (urinalysis) → C&S: WBCs in the urine lead to a culture and sensitivity. The culture names the organism; the sensitivity shows which antibiotic works. Collect cultures before antibiotics.
• Chest x-ray: confirms pneumonia or atelectasis but not the type.
• Antibody test: shows past exposure, not current infection. Antigen test and NAAT (nucleic acid amplification test) detect the pathogen itself.
• Gallium scan: radioactive tracer gathers where WBCs collect.

Hand hygiene

Handwashing essentials: soap, running water, friction. Hands below elbows, warm water, wash 1 in above the wrist, clean under nails (the subungual area holds the most microbes), rinse fingertips down, pat dry fingertips to wrists, turn the faucet off with a dry paper towel.

Nails: natural, ≤0.25 in, unpolished. No artificial nails; chipped or gel polish harbors bacteria.

Asepsis

Sterilization kills everything, including spores (autoclave, chemical, radiation). Disinfection kills most but not all: high-level leaves some spores (endoscopes); low-level is for surfaces and not for visible blood. Always clean off visible soil first. Check for latex allergies before any aseptic procedure.

Sterile field rules

• Waist-high flat surface, close to the client, 12–18 in from walls
• Outer 1-inch border is contaminated
• Below the waist or above the chest is contaminated
• Never reach over it, turn your back on it, or cough or talk over it
• Wet = contaminated (moisture wicks microbes through)
• A long delay contaminates it
• Drop items into the center from about 6 in
• Pour solution: cap face-up, label in palm, pour off 1–2 mL first
• Client coughing? Put a mask on the client

Opening a sterile package

Sterile gloving: open technique when no gown is worn; closed technique with hands inside the gown cuffs. A sterile gown is sterile only on the sleeves from just above the cuff to 2 in above the elbow; the axilla and back are not.

Precautions and PPE

Clients on airborne, droplet, or protective precautions wear a mask when they leave the room. Isolation raises the risk of loneliness and depression, so explain why it's needed and provide stimulation.

Putting PPE on

Taking PPE off

• Touch only ties, ear loops, and headbands when removing PPE; the fronts are contaminated
• Gowns are single use; roll inside out and discard before leaving the room
• N95 fit check: inhale and it collapses; exhale and no air leaks
• Change gloves if torn, between body sites, before touching keyboards, and between clients
• Exposed to blood? Wash with soap and water (eyes: irrigate; nose or mouth: flush), then report right away
• Sharps box less than ¾ full; engage safety devices; always report needlesticks
• Linens: bag at the bedside, never shake or sort, double-bag if leaking

Health care–associated infections (HAIs) and multidrug-resistant organisms (MDROs)

An HAI is an infection a client picks up while receiving care in a health care facility. The 4 major HAIs:

• CLABSI: central line–associated bloodstream infection
• CAUTI: catheter-associated urinary tract infection
• SSI: surgical site infection
• VAP: ventilator-associated pneumonia

Invasive devices create an extra portal of entry. The urinary tract is the most common HAI site, and hand hygiene is the best prevention.

MDROs resist one or more classes of antimicrobials and respond to only 1–2 drugs. Use contact precautions. MRSA is treated with vancomycin or linezolid. Teach clients to finish the full antibiotic course.

• MRSA: methicillin-resistant Staphylococcus aureus
• VRE: vancomycin-resistant Enterococcus
• VRSA: vancomycin-resistant S. aureus
• VISA: vancomycin-intermediate S. aureus
• ESBL: extended-spectrum beta-lactamase–producing organisms
• MDRSP: multidrug-resistant Streptococcus pneumoniae

Enhanced barrier precautions (nursing homes): gown and gloves for high-contact care like bathing, toileting, wound care, and transfers.

Skin structure and function

Skin functions: barrier against injury, infection, UV, and temperature changes; sensation; waste elimination; vitamin D synthesis.

Highest risk ages: early and late life. Older adults have thinner skin with less collagen, elasticity, padding, blood supply, and hydration, so they get skin tears (often from tape) and pressure injuries. Obese clients are at risk from moisture in skin folds. Moisture-associated skin damage (MASD) is skin damage from urine, stool, effluent, or exudate.

Assessing skin color

Blanchable erythema turns white when pressed and comes back. Nonblanchable stays red and means small-vessel damage. Feel temperature with the back of your hand: warm = inflammation, cool = poor blood flow.

Also check: turgor (tenting = dehydration; unreliable in older adults), capillary refill (<3 sec), clubbing (nail angle >160°).

Skin lesions

Expected aging: thin, dry, wrinkled, less elastic skin. Hematomas and petechiae are not expected.

Pressure injuries

Localized damage to skin and tissue from pressure, or pressure plus shear, usually over bony prominences or medical devices. Most at risk: heels, toes, sacrum, hips, elbows, shoulders, back of head. Deep damage may not show for 24–72 hr.

Top risk factors: immobility, malnutrition, reduced perfusion, sensory loss, decreased level of consciousness.

Braden Scale: 6 categories (sensory perception, moisture, activity, mobility, nutrition, friction and shear). Scores 6–23; lower score = higher risk.

Staging

Practice: stage these from the photos

Device-related injuries take the shape of the device. Mucosal injuries from devices can't be staged. Hospital-acquired pressure injuries (HAPIs): CMS (Centers for Medicare & Medicaid Services) limits payment for stage 3 and 4.

Dark skin: temperature and moisture changes may come first; also check for hardness, edema, pain, and areas darker than surrounding skin.

Document: location, stage, size, tissue, wound bed color, edges, surrounding skin, undermining and tunneling, drainage, odor, pain.

Prevention

• Reposition at least every 2 hr in bed, every 1 hr in a chair; weight shifts every 15 min if able
• Side-lying at a 20–30° tilt; head of bed 30° or lower
• Lift, don't pull; raise heels off the bed
• Pressure-redistributing mattress; gel, air, or foam seat cushion
• Silicone foam dressing on sacrum and heels within 24 hr of admission
• Incontinence: gentle cleanser, tepid water, pat dry, dimethicone barrier
• Assess skin on admission (within 24 hr) and with every change in condition

Wound assessment

Measuring: length head-to-toe, width side-to-side, depth at the deepest point, all in cm. Use the same method every time. For tunneling and undermining, use the clock: 12:00 is toward the head. Depth: premoistened sterile applicator until resistance.

Expected incision: red days 1–4, bright pink days 5–14, pale pink day 15 to 1 year. Edema and drainage resolve by postoperative day 5.

Wound care

Debridement removes dead tissue: surgical (scalpel or scissors) or biological (medical-grade maggots). Irrigation usually uses 0.9% NaCl (sodium chloride, normal saline) at 5–8 psi (30–60 mL syringe with a 19-gauge needle), tip 1 in above the wound, until it runs clear. Clean from least to most contaminated with a new gauze each stroke.

A healing wound bed should be moist, not wet. Use sterile technique for the first 24–48 hr after surgery, then clean technique.

Semiocclusive dressings allow some gas exchange; occlusive dressings seal completely.

Closures

• Staples: faster to place; removed in 7–14 days; not on the face or neck
• Nonabsorbable sutures: out by day 14
• Skin adhesive: small straight wounds, not over joints; 3–4 layers, hold edges 1 min each; peels off in 5–10 days
• Negative pressure wound therapy (NPWT): wound vac; foam plus a sealed dressing under suction; reduces edema and builds granulation
• Montgomery straps: tie-closed adhesive strips that hold dressings needing frequent changes, so tape doesn't come off the skin each time

Drains

Drainage goes from sanguineous to serosanguineous. Call the provider for a big change in amount, clots, signs of infection, or accidental removal. Some tenderness the first few days is expected.

Wound healing

Phases

• Inflammatory (hemostatic): bleeding stops, then WBCs clean the wound
• Proliferative: granulation tissue and collagen fill in; edges contract
• Remodeling: stronger collagen forms, but the scar stays weaker than the original skin

What helps and what hurts

Needs: protein, vitamins A and C, zinc; at least 2,500 mL/day fluid (unless contraindicated) and at least 1,500 kcal/day. Albumin below 3.5 g/dL increases risk.

Delays healing: diabetes (poor perfusion and sensation), infection, corticosteroids (block collagen), anti-inflammatories and antineoplastics, malnutrition, necrosis, hypoxia, multiple wounds, obesity, smoking, low hemoglobin, coughing or vomiting (wound stress), older age.

Complications

Evisceration: what to do

1. Call for help and stay with the client
2. Cover with sterile saline-soaked dressings. Never push organs back
3. Supine with hips and knees bent
4. NPO (nothing by mouth) and watch for shock

Prevent it: splint the incision with a pillow when coughing. Risk factors include obesity, abdominal surgery, straining, malnutrition, infection, and radiation. A binder helps prevent, not treat, evisceration.

SSIs: superficial within 30 days, deep within 30 or 90 days. Most common cause: S. aureus. Chlorhexidine wipes before surgery reduce risk.

Delegation

Blood specimens

Capillary (fingerstick)

• Usual site: fingers. Alternatives: palms, forearms, earlobes
• Clean with facility antiseptic or soap and water; choose a vascular site
• Poor circulation? Have the client warm their hands or let them dangle
• Lancet on the side of the finger, not the central tip (more nerves there)
• Don't milk the finger: it can lyse (break) blood cells and alter results
• Wipe away the first drop; apply blood when the meter prompts
• Hold a tissue or cotton ball on the site; usually no bandage needed
• Document method, client tolerance, and findings

Blood glucose meters

Expected fasting glucose: 74–106 mg/dL. Readings below 60 or above 400: retest and possibly send a sample to the lab, since bedside meters are less accurate than lab testing. Store strips closed at room temperature, check the expiration date, and match lot numbers; poor storage causes falsely high or low readings.

Venipuncture

1. Explain the procedure; choose a vein in the arm or hand (a transilluminator can help)
2. Tourniquet above the site; client pumps the hand; stroke distal to proximal, no vigorous rubbing
3. Remove the tourniquet once the site is chosen; clean with antiseptic and let it dry completely
4. Draw into evacuated tubes (cap color = which test); bandage the site and document

Needle gauge: the larger the number, the smaller the opening (18-gauge is bigger than 22-gauge). Butterfly needles are smaller and less painful for children or needle-averse clients but can lyse cells for some tests.

Stool

• Amount: formed stool 1 inch (walnut-sized); liquid stool 15–30 mL
• Have the client urinate first, then deposit stool in a dry, clean container. No urine, water, or toilet tissue
• Transfer with a tongue blade; some tests need a preservative (keeps parasites alive)
• Ova and parasites: three separate specimens
• Testing for C. diff? Contact isolation until results come back

Fecal occult blood test (FOBT)

Also called a guaiac test. Screens for colorectal cancer and detects GI bleeding. Recommended for clients over 50 before colonoscopy; three home samples are more accurate than one office test. Only valid for stool, not gastric contents.

Dark, tarry stool = bleeding high in the GI tract. Bright red streaks = bleeding low (hemorrhoids, menstrual blood) and may give an inaccurate result.

Urine

Document the collection method, client tolerance, and the urine's color, clarity, and odor. Refrigerate or keep on ice until transport.

From an indwelling catheter

24-hour urine

1. Client voids; discard it and note the start time
2. Save all urine for 24 hours, on ice or refrigerated per lab guidelines
3. Client voids at the end; include it
4. If a void is discarded by mistake, restart the timing. Never take urine out of the container for other tests

Timed urines (usually 24 hr, sometimes 2 or 12 hr) measure creatinine clearance, protein, or hormones. Pregnancy test: first morning void (detects hCG); document the last menstrual period.

Dipstick (reagent strip)

Everything except pH and specific gravity should be negative. Dipsticks are screening only; confirm abnormal results with the lab.

Cultures and swabs

Wound culture

1. Remove the old dressing; change gloves and perform hand hygiene
2. Clean the wound with sterile water or 0.9% NaCl; change gloves again
3. Swab clean tissue in the center of the wound, not the edges. Never pooled exudate
4. Into the tube, cap it, squeeze to activate the medium
5. Label, requisition, biohazard bag, redress, document (vital signs, date, time, location, tolerance)

Collect before broad-spectrum antibiotics; if the client is already on them, note it on the requisition. A Gram stain lets the provider treat sooner than waiting for culture results. Report fever above 104°F (40°C) with hypotension right away: possible sepsis.

Throat culture

• Client sitting upright, head tilted back, tongue out, says "ah"; penlight
• Swab path: right tonsil → right arch → uvula → left arch → left tonsil
• Avoid gums, tongue, teeth, lips, and cheeks. Touched them? Discard and start over
• Epiglottis severely inflamed? Don't swab; notify the provider
• Point-of-care swab tests are less accurate; confirm positive results

Sputum

• Morning, before eating or drinking
• Rinse with water (no mouthwash), deep breaths, cough; don't touch inside the cup
• Amount: 1–2 teaspoons (5–10 mL)
• Can't produce enough? Chest physiotherapy first; suctioning and transtracheal aspiration are last resorts
• AFB (acid-fast bacilli, for TB): 3 serial samples in a sterile container. Cytology: needs a preservative; identifies lung cancer type