Basic Considerations - Wound Healing

What defines an Acute Wound chronologically?

A wound that has occurred in the past 3 to 4 weeks

What defines a Chronic Wound chronologically?

A wound that has persisted beyond 4 to 6 weeks

What is the Age of Wound difference between Tetanus Prone and Non-Tetanus Prone wounds?

Tetanus Prone: More than 6 hours; Non-Tetanus Prone: 6 hours or less

What is the Configuration difference between Tetanus Prone and Non-Tetanus Prone wounds?

Tetanus Prone: Stellate wound, avulsion, abrasion; Non-Tetanus Prone: Linear

What is the Depth difference between Tetanus Prone and Non-Tetanus Prone wounds?

Tetanus Prone: More than 1 cm; Non-Tetanus Prone: 1 cm or less

What is the Mechanism of Injury difference between Tetanus Prone and Non-Tetanus Prone wounds?

Tetanus Prone: Missile, crush, burn, frostbite; Non-Tetanus Prone: Sharp surface (e.g., knife or glass)

How do Signs of Infection, Devitalized tissue, and Contaminants differ between Tetanus Prone and Non-Tetanus Prone wounds?

Tetanus Prone: Present; Non-Tetanus Prone: Absent

What infection rate, description, and surgical examples define Class I Clean operative wounds?

Infection rate: 1-2%; Atraumatic, uninfected, no entry of GU/GI/respiratory tract, primarily closed; Examples: Breast surgery (MRM), thyroid surgery, inguinal hernia, operative incisional wounds following non-penetrating trauma

What infection rates define Class II Clean-Contaminated operative wounds in elective GI vs colorectal surgery?

Elective GI Surgery: 2.1-9.5%; Colorectal Surgery: 4-14%

What description and surgical examples define Class II Clean-Contaminated operative wounds?

Wound involving normal but colonized tissue, minor breaks in sterile technique, entry into GU/GI/respiratory tract without significant change; Examples: Operations involving biliary tract, appendix, vagina, and oropharynx

What infection rate, description, and surgical examples define Class III Contaminated operative wounds?

Infection rate: 3.4-13.2%; Wound containing foreign/infected material, traumatic wounds, open fresh accidental wounds, gross spillage from GI tract, entry into infected tissue/bone/urine/bile; Examples: Operations with major breaks in sterile technique, incisions with acute non-purulent inflammation (e.g., dry gangrene)

What infection rate, description, and surgical examples define Class IV Dirty operative wounds?

Infection rate: 3.1-12.8%; Old traumatic wounds with retained devitalized tissue and those involving existing clinical infection/perforated viscera; Examples: Drainage of abscess, debridement of soft tissue infection, resection of infarcted bowel

What sequence of cell types peak during the Hemostasis and Inflammation phase (Day 0-6) of wound healing?

PMNs peak at 24-48 hours, Macrophages peak at 48-96 hours, T cells peak at 1 week post-injury

What primary events, key growth factor, and collagen type characterize the Proliferation phase (Day 4-12) of wound healing?

Invasion of fibroblasts and endothelial cells (angiogenesis); PDGF is strongest chemotactic factor for fibroblasts; deposition of type III collagen fibers

What collagen transition, enzyme mediator, and ultimate strength percent characterize Maturation and Remodeling (Day 8 - months)?

Shift of type III collagen fibers to type I collagen fibers; mediated by matrix metalloproteinases; scar strength achieves 75%-80% of normal tissue

What primary process defines the Epithelialization phase of wound healing?

Proliferation and migration of epithelial cells; once layering is re-established, surface will keratinize

What cell type and intracellular component cause Wound contraction?

Caused by myofibroblasts due to presence of actin filaments

What characteristics define Primary Closure (healing by primary intention)?

Requires clean tissue approximated without tension; includes direct approximation, pedicle flap, or skin grafts; dermis approximated with sutures or skin glue

What characteristics define Secondary Healing (healing by secondary intention)?

Wound left open to heal spontaneously after wound toilet and surgical debridement; closure depends on contraction and epithelialization by myofibroblasts; beneficial in heavily contaminated wounds; treated with wet-to-dry dressings

What characteristics define Tertiary Healing or Delayed Primary Closure?

Wound initially managed as secondary intention (left open with dressing changes), then closed after a few days when wound is clean and granulation tissue is abundant; used for traumatic injuries, dog bites, or foreign body lacerations

What local factors impair wound healing?

Infection, foreign bodies, ischemia/hypoxia, venous insufficiency, toxins (e.g., spider venom), previous trauma, radiation, and cigarette smoking

What systemic factors impair wound healing?

Malnutrition, cancer, diabetes mellitus, uremia, jaundice, old age, systemic corticosteroids, chemotherapeutic agents, and alcoholism

What four criteria defined Systemic Inflammatory Response Syndrome (SIRS) under the old definition (2 or more required)?

Temp >= 38°C or <= 36°C, HR > 90 beats/min, RR >= 20/min or PaCO2 <= 32mmHg or mechanical ventilation, WBC >= 12,000/μL or <= 4,000/μL or >= 10% bands

What parameters and cut-offs define quick SOFA (qSOFA)?

Respiratory Rate (RR) >= 22/min (1 point), Altered mental status or GCS < 15 (1 point), Systolic blood pressure (SBP) <= 100mmHg (1 point)

What qSOFA score warrants further investigation of organ dysfunction and/or escalation of therapy?

Score >= 2

What modern definition identifies Sepsis under updated consensus definitions?

Life-threatening organ dysfunction due to a dysregulated host response to infection, defined as an increase in Sequential (Sepsis-Related) Organ Failure Assessment (SOFA) score of >= 2 points

What clinical criteria identify Septic Shock?

Need for vasopressors to obtain a MAP >= 65mmHg despite adequate fluid resuscitation, and an increase in lactate concentration > 2 mmol/L in the absence of hypovolemia

What defines Contamination, Colonization, and Infection in sepsis terminology?

Contamination: presence of organisms on the surface of a wound; Colonization: presence of multiplying organisms on the surface of a wound; Infection: presence of multiplying organisms which overwhelm the body's immune system

In the SOFA score, what PaO2/FiO2 values correspond to scores 0 through 4?

0: >=400; 1: <400; 2: <300; 3: <200 with respiratory support; 4: <100 with respiratory support

In the SOFA score, what Platelet counts correspond to scores 0 through 4?

0: >=150; 1: <150; 2: <100; 3: <50; 4: <20

In the SOFA score, what Bilirubin levels (mg/dL) correspond to scores 0 through 4?

0: <1.2; 1: 1.2-1.9; 2: 2.0-5.9; 3: 6.0-11.9; 4: >12.0

In the SOFA score, what MAP or vasopressor doses correspond to scores 0 through 4?

0: MAP >=70 mmHg; 1: MAP <70 mmHg; 2: Dopamine <5 or Dobutamine (any dose); 3: Dopamine 5.1-15 or Epinephrine <0.1 or Norepinephrine <0.1; 4: Dopamine >15 or Epinephrine >0.1 or Norepinephrine >0.1

In the SOFA score, what Glasgow Coma Scale (GCS) scores correspond to scores 0 through 4?

0: 15; 1: 13-14; 2: 10-12; 3: 6-9; 4: <6

In the SOFA score, what Creatinine levels and urine output correspond to scores 0 through 4?

0: Creatinine <1.2; 1: Creatinine 1.2-1.9; 2: Creatinine 2.0-3.4; 3: Creatinine 3.5-4.9 or urine output <500 mL/day; 4: Creatinine >5 or urine output <200 mL/day

What fluid volume and target MAP guide initial resuscitation in sepsis management?

30mL/kg IV crystalloids in first 3 hours; target MAP >= 65mmHg

What timing strategy is used for blood cultures and antibiotics in sepsis management?

Obtain cultures before antibiotics; administer empiric broad-spectrum IV antibiotics then adjust based on culture-guided results

What procedures constitute source control in sepsis management?

Emergent surgery, drainage, or evacuation

What is the first-choice vasopressor in septic shock, and what secondary agents may be added or used?

Norepinephrine is 1st choice; Vasopressin, Epinephrine, Dopamine, or Dobutamine may be used; GOAL is MAP >=65mmHg

When are systemic steroids indicated in septic shock, and what is the standard regimen?

Indicated in unresponsive septic shock; IV Hydrocortisone 200mg/day

What are the specific blood transfusion thresholds for pRBCs and platelets in sepsis management?

pRBC for Hgb < 7g/dL; Platelet transfusion for < 10,000/mm3 even without bleeding, < 20,000/mm3 for high risk of bleeding, or > 50,000/mm3 for active bleeding

What mechanical ventilation parameters are targeted in sepsis management?

Target tidal volume (TV) = 6mL/kg and max plateau pressure <30 cmH2O

What target blood glucose level is maintained in sepsis management?

Target glucose <=180 mg/dL

What modalities are used for renal replacement therapy in stable vs unstable septic patients?

Intermittent HD in stable patients; Continuous HD in unstable patients

What medical prophylaxes are routinely implemented in sepsis management?

Prophylaxis for venous thromboembolism (VTE), stress ulcers, and ventilator-associated pneumonia (VAP)

Which statement is true regarding gram-negative bacterial septicemia?

Adverse changes can be accounted for by lipid A release

What defines Surgical Site Infections (SSIs)?

Infections of the tissues, organs, or spaces exposed by surgeons during performance of an invasive procedure

What timeframe and depth criteria define Superficial Incisional Surgical Site Infection (SSI)?

Occurs within 30 days post-op involving ONLY skin and subcutaneous tissue of the incision

What criteria must be present to diagnose Superficial Incisional SSI?

Purulent drainage, positive culture, surgeon diagnosis, or local signs (pain/tenderness, localized swelling, redness, heat, opened by surgeon)

Which conditions are explicitly NOT reported as Surgical Site Infections (SSIs)?

Stitch abscess, episiotomy/circumcision infection, infected burn wound, incisional SSI extending into fascial/muscle layers

What timeframe and depth criteria define Deep Incisional Surgical Site Infection (SSI)?

Occurs within 30 or 90 days (or within 1 year if implant in place) involving deep soft tissues (fascial and muscle layers)

What criteria must be present to diagnose Deep Incisional SSI?

Purulent drainage from deep incision, spontaneous dehiscence or surgeon opening with fever (>38°C) or localized pain, abscess or evidence of infection on examination/histopathology/imaging

How are infections involving both superficial and deep incision sites reported?

Reported as deep incisional SSI

How is an organ/space SSI that drains through the incision reported?

Reported as deep incisional SSI

What timeframe and depth criteria define Organ/Space Surgical Site Infection (SSI)?

Occurs within 30 days (or within 1 year if implant in place) involving any part of the anatomy (organs or spaces) other than the incision opened/manipulated during operation

What criteria must be present to diagnose Organ/Space SSI?

Purulent drainage from a stab wound drain, positive organ/space culture, abscess or evidence of infection on examination/histopathology/imaging, or surgeon diagnosis

What patient factors influence the risk of Surgical Site Infection (SSI)?

Comorbid illness (diabetes, PVD, ascites, hypocholesterolemia, anemia, chronic inflammatory disease, skin disease), nutritional state (malnutrition, obesity), avoidable factors (preoperative shaving, extended preoperative admission), and remote infection/steroids/radiation/hypoxemia

What environmental and treatment factors influence the risk of Surgical Site Infection (SSI)?

Environmental: Inadequate sterilization, inadequate disinfection or skin antisepsis; Treatment: Emergency procedure, failure to obliterate dead space, hypothermia, inadequate antibiotic prophylaxis, surgical drains, poor hemostasis, tissue trauma, prolonged operative time

What are the recommendations for parenteral antimicrobial prophylaxis in clean and clean-contaminated procedures?

Give when indicated so bactericidal concentration is present when incision is made; no additional doses needed after incision is closed in OR, even with a drain

What are the recommendations for non-parenteral antimicrobial prophylaxis regarding topical agents and sutures?

Do not apply antimicrobial agents (ointments, solutions, powders) to surgical incision; consider triclosan-coated sutures

What target glucose level is recommended for perioperative glycemic control in surgical patients?

Target glucose level <200 mg/dL in patients with and without diabetes

What antiseptic prophylaxis steps are recommended preoperatively and intraoperatively?

Shower or bathe with soap/antiseptic at least the night before; perform intraoperative skin preparation with alcohol-based antiseptic agent; plastic adhesive drapes not necessary

What is the general preoperative timing for administering standard parenteral prophylactic antibiotics versus vancomycin?

Standard antibiotics: within 60 minutes before incision; Vancomycin: within 120 minutes before incision

When is re-dosing of parenteral prophylactic antibiotics indicated during surgery?

If duration of surgery exceeds 2 half-lives of the antimicrobial or if there is excessive blood loss

What is the general principle regarding the overall duration of routine prophylactic antibiotic regimens after surgery?

Limit antibiotic regimen to no more than 24 hours after surgery

What standard antibiotic and penicillin-allergic alternatives are recommended for Cardiovascular surgery?

Standard: Cefazolin, cefuroxime; Penicillin-allergic: Vancomycin, clindamycin

What standard antibiotic and penicillin-allergic alternatives are recommended for Gastroduodenal area, non-obstructed small intestine?

Standard: Cefazolin; Penicillin-allergic: Clindamycin or vancomycin + aminoglycoside/aztreonam/fluoroquinolone

What standard antibiotic and penicillin-allergic alternatives are recommended for Open biliary tract procedures or high-risk laparoscopic procedures?

Standard: Cefazolin, cefoxitin, cefotetan, ceftriaxone, ampicillin-sulbactam; Penicillin-allergic: Clindamycin or vancomycin + aminoglycoside/aztreonam/fluoroquinolone OR Metronidazole + aminoglycoside/fluoroquinolone

What antibiotic prophylaxis is recommended for low-risk laparoscopic biliary tract surgery?

None

What standard antibiotics and penicillin-allergic alternatives are recommended for uncomplicated appendectomy?

Standard: Cefoxitin, cefotetan, cefazolin + metronidazole; Penicillin-allergic: Clindamycin or metronidazole + aminoglycoside/aztreonam/fluoroquinolone

What standard antibiotics and penicillin-allergic alternatives are recommended for colorectal surgery or obstructed small intestine?

Standard: Cefazolin or ceftriaxone + metronidazole, ertapenem, cefoxitin, cefotetan, ampicillin-sulbactam; Penicillin-allergic: Clindamycin or metronidazole + aminoglycoside/aztreonam/fluoroquinolone

What standard antibiotics and penicillin-allergic alternatives are recommended for clean-contaminated head and neck surgery?

Standard: Cefazolin or cefuroxime + metronidazole, ampicillin-sulbactam; Penicillin-allergic: Clindamycin

What standard antibiotic and penicillin-allergic alternatives are recommended for neurosurgical procedures?

Standard: Cefazolin; Penicillin-allergic: Clindamycin, vancomycin

What standard antibiotics and penicillin-allergic alternatives are recommended for orthopedic surgery?

Standard: Cefazolin, ceftriaxone; Penicillin-allergic: Clindamycin, vancomycin

What standard antibiotic and penicillin-allergic alternatives are recommended for breast and hernia surgery?

Standard: Cefazolin; Penicillin-allergic: Clindamycin, vancomycin

What are the 5 Classic W's of Postoperative Fever and their corresponding timing/causes?

Wind: Atelectasis (<48 hours), Pneumonia (>48 hours); Water: UTI (3-5 days); Walk: DVT (4-6 days); Wound: SSI (5-7 days); Wonder drugs: Medications (>7 days)

In a surgical wound healing well 3 days post-op, which cell type is expected to be most abundant?

Macrophages

Which type of collagen is most important for wound healing?

Collagen type I

What surgical wound class is assigned to a perforated appendix with severe abdominal pain and rigidity?

Dirty

What type of wound healing occurs via epithelialization and contraction without repair using sutures or staples?

Secondary intention

What is the appropriate wound management for a dog bite on the calf after rabies and tetanus post-exposure prophylaxis?

Tertiary healing (or delayed primary closure) / No immediate closure

Which parameter (e.g., Systolic BP of 90 mmHg) is NOT consistent with SIRS criteria?

Systolic BP of 90 mmHg

For a 70-year-old woman in septic shock, which management statement is incorrect?

All of the choices are incorrect (or starting antibiotics before drawing blood for culture)

Which post-op presentation is considered a true Surgical Site Infection (SSI)?

Purulent discharge on breast JP drain after MRM

Which factor does NOT influence the risk of developing an SSI among choices like general anesthesia?

General anesthesia

Which statement is TRUE regarding surgical antimicrobial prophylaxis?

Initial dose of antibiotic should be given within 30 to 60 minutes prior to incision