Wound infection

Wound infection

1. Wound Infection Prepared by Pranjal Rokaya Resident General Surgery KIST MCTH 30 August 2022

2. Outline Introduction Wound Healing Classification of Wound/SSI Wound Complications Prevention of SSI General management

3. Wound Disruption in normal structure and function of skin and soft tissue architecture. Infection: Invasion of organism into tissue following the breakdown of local and systemic host defenses. Major complications of trauma and surgery documented for 5000 years. Hippocratic teachings: Use of wine and vinegar Galen recognized suppuration heralded recovery. Koch’s postulates Ignac Semmelweis Identification of microbes and development of antiseptics.

4. Normal wound healing Hemostatic phase (within minutes) Inflammatory phase (0-3 days) Proliferative phase (3 days to 3 weeks) Remodelling phase ( 3 weeks to years)

5. Types of Wound closure and healing Primary intention Wound edges opposed Normal healing with minimal scar 2. Secondary intention Wound left open Heals by granulation, contraction, and epithelialization. 3. Tertiary intention Wound initially left open. Edges later opposed when healing condition favorable .

6. Factors influencing healing of wound Site of the wound Structures involved Mechanism of injury Level of contamination Loss of tissue Local factors (eg. V ascular insufficiency, previous radiation) Systemic factors (eg. Malnutrition, DM, steroid use, AIDS)

7. Types of wound Acute Vs Chronic Tidy vs Untidy Surgical Wounds/Infection Clean Clean Contaminated Contaminated Dirty Superficial Deep Organ/Space Endogenous Exogenous

8. Classification of Surgical Wound Clean No hollow viscus entered Primary wound closure No inflammation No break in aseptic technique 1-3 % 2. Clean Contaminated Hollow viscus entered but controlled Minor breach in aseptic technique Mechanical drains used. Preoperative bowel preparation done 5-8% 3. Contaminated Uncontrolled spillage from viscus Inflammation appar e nt Open traumatic wound 20-25% 4. Dirty Pus in operative wound, open suppurative wound Severe inflammation 30-40%

9. Wound complications Seroma Hematoma Wound Infection (Surgical Site Infection)

10. a. Seroma formation Collection of fluid containing fat, serum, or lymph that develops at surgical wound or dead space. Common in procedures which create dead space or interrupts lymphatic drainage. Presents as palpable SQ fluid collections under or adjacent to a skin incision. Diagnosis based on an examination, USG or CT scan. An asymptomatic seroma may spontaneously resolve, symptomatic should be aspirated and pressure dressing applied. In refractory seromas, drain can be placed and packed to heal by secondary intention.

11. b. Hematoma Collection of blood clots and blood at the surgical site. Includes the SQ tissues and may be found in deeper tissue space. May be caused by incomplete surgical hemostasis or medical conditions that impair clotting or conditions that impair hemostasis (eg: cirrhosis, uremia, sepsis). Superficial hematoma may present with skin discoloration, SQ swelling and pain of affected area. Hematoma of other location may cause pressure effects and irritation depending upon anatomic location.

12. ….contd If clotting disorders present, bleeding may persist and large hematoma may present with anemia or hypovolemia. The appropriate evaluation of bleeding disorders and anticoagulants to assess coagulopathy. History related to hemostasis such as liver or kidney diseases or a family history of bleeding disorder should raise concern for hemostatic abnormality.

13. 0-1: Low risk; 2: Intermediate risk; >3 High risk High risk of bleeding (2-4%): Cardiovascular, Orthopedic, Surgery of head and neck, Urologic Surgery, Surgery more than 45 minutes. Low risk of bleeding (0-2%) : Anticipated surgical time <45 mins, abdominal hernias, cholecystectomy.

14. c. Wound Infection (Surgical Site Infection ) Infection related to surgical procedure that occurs near the surgical site . within 30 days following surgery 90 days following surgery where implant is used. Associated with : Significant morbidity and mortality. Transfer to ICU setting. Prolonged hospitalizations . Hospital readmission.

15. Incidence In USA, 2-4% annually develop SSI. Incidence varies widely ranging from 5-40% depending upon the operative site and wound classification. Colon surgery: 10% [4] Coronary bypass:3.3 to 3.7% Vascular surgery : 0.16 to 29% [5] Caeserian delivery: 3.4-30 % [6] Spinal fusion : 1.3-3.1 %

16. 1. Risk assessment Patient factors Older age Immunosupression Obesity Diabetes Mellitus Malnutrition Smoking CKD Peripheral Vascular disease Anemia Radiation Chronic skin disease Local Factors Open compared to Laparosopic surgery Prior skin preparation. Contamination of instruments. Inadequate antibiotic prophylaxis. Prolonged procedure. Local tissue necrosis. Blood transfusion. Hypothermia. Microbial factors Prolonged hospitalization. Toxin Secretion Resistance to clearance.

17. 2. Prevention of Surgical Site Infection

18. a. Patient Optimization Treatment of active and remote infection as much as feasible. Treat hypoalbuminemia (six fold increase in SSI vs normal albumin). Diabetic control. Laparoscopic procedures are generally associated with lower rates of SSI. Delay of elective procedures in chemo/radiotherapy patients. Smoking cessation four to six weeks prior to elective surgery.

19. b. Preoperative preparation Short preoperative hospital stay. Washing of hands before and after patient contact. Antiseptic bath. Preoperative skin shaving just prior to surgery (hair clipping has lowest rate of SSI).

20. c. Infection control measures Use of face mask and protective spectacles. Waterproof disposable gowns and drapes. Boots to avoid injury from dropped sharps. Double gloving. Removal of false nails, clipping nail length and removal of watches and finger rings. Jewelry on head and neck be removed or covered.

21. d. Prophylactic antibiotics Effective in reducing the risk of infection in clean-contaminated and contaminated operations. Used before the bacterial growth becomes established. Intravenous administration at time of induction is optimal. May be repeated 4 hourly in long operations or unexpected. contamination22

22. e. Perioperative measures Maintaining normothermia. Limiting traffic through operating room. Use of laminar air flow; use of novel air barrier system. Use of supplemental oxygen prior to surgery. Restrictive transfusion reduces risk of SSI. Routine application of antiseptic( chlorhexidine/alcohol based) prior to surgery. Changing outer gloves and using new instruments for closure in open colorectal surgery.

23. f. Surgical technique Gentle traction Effective hemostasis Removal of devitalised tissue Minimisation of cautery Obliteration of dead space Antibacterial irrigation a/w lower risk of SSI in intracavitary operations. The use of a wound protector reduces SSI compared to standard care.

24. 3 . Clinical features a. Superficial SSI Localized swelling, warmth, drainage with or w/o odor, wound breakdown, and separation Peri incisional erythema and pain at the incision site. b. Deep SSI Same as above More often accompanied by fever and local tenderness c. Organ/Space SSI Malaise, fever, tenderness in body region where the operation was performed without overlying skin changes.

25. Recognizing necrotising infection Periincisional pain is severe and out of proportion to the expected degree of postoperative pain. May have skin discoloration, blistering and devitalization. Copious dishwater like drainage, dusky and friable subcutaneous tissue. Extent of infection may not be appar e nt on visual inspection .

26. 4. Diagnosis Superficial SSI can be fully evaluated through direct observation. Imaging USG can identify the presence of fluid in subcutaneous tissue. In deep/organ space infection, CT or MRI may be helpful. Oral contrast studies in the setting of prior GI resection. Gram stain and culture.

27. 5. General management

28. Wound exploration and debridement The wound should be opened, infected fluid drained and sent for culture. Wounds that have devitalized edges, purulent collection, and residual suture material benefit from debridement prior to further management. Performed with forceps, scalpel or scissors. For SSI of laparotomy wounds, the benefits of removal of exposed fascial sutures outweighed by the risk of evisceration. Serial debridement until no necrotic tissue remains.

29. b. Irrigation Important for decreasing bacterial load and removing loose material. Low-pressure irrigation is performed using a syringe. High-pressure irrigation is performed in an operative setting using a commercial device. Warm isotonic saline is typically used, the addition of dilute iodine or other antiseptic solutions is generally unnecessary.

30. c. Antibiotic therapy Determined by the extent of infection, presence of systemic manifestations, previous antibiotics, resistance pattern, and patient comorbidities. Initiated in following clinical circumstances Cellulitis a/w intact but indurated surgical incision. Persistent cellulitis in surrounding skin after wound opening. Subcutaneous or deeper tissue has persistent inflammation after debridement or drainage. Implanted material is present within the infected area. Systemic signs of infection. Septic shock.

31. d . Wound management Open wound care The mainstay is healing by secondary intention with serial dressing consisting of frequent wound packing and removal. Disadvantages include chances of recurrent infection, painful and cumbersome for the patient. II. Wound packing Dressing that maintain moisture and warmth facilitate healing. Wound fluids contain tissue growth factors that facilitate reepithelialization and promote autolytic debridement.

32. Gauze moistened with normal saline placed into wound and covered with dry layers of gauge. When the gauge is removed, necrotic tissues are removed with it. Once debridement is not necessary, packing material should be changed from gauze to less traumatic materials. Dressing changes continued until the wound surface is mostly covered by granulation tissue C an be changed OD or every other day to avoid disturbing the healing process.

33. Ideal dressing Absorbs excessive wound fluid while maintaining a moist environment. Protects from mechanical and caustic damage. Prevents bacterial invasion or proliferation. Confirms to wound shape and eliminates dead space. Debrides necrotic tissues. Doesn’t macerate surrounding viable tissue. Achieves hemostatis and minimizes edema via compression. Doesn’t shed fibres of any foreign body. Minimises dressing changes. Is inexpensive and transparent.

34. Negative pressure wound therapy Alternative to wound healing by secondary intention with wound packing. Can be applied to open wound with a clean, granulating base. Reduces excess fluid accumulation and increases blood supply. Protects the skin from frequent dressing changes. Relatively contraindicated in conditions where blood vessels or intestines are exposed.

35. e. Delayed primary closure and reconstrution Wound that are opened often left to heal by secondary intention. The benefit of more rapid wound healing but risk of recurrent infection. Wound with skin contracture or tissue loss from debridement may require skin grafting or flap reconstruction. Nutritional support and meticulous wound care are critical for preparing wound bed. Presence of granulation tissue in wound bed signals adequate blood and nutrition supply.

36. Summary SSI is an infection related to a surgical procedure that occurs near the surgical site within 30 days of surgery. Types: Superficial, deep and organ/space. Risk factors are similar to those a/w impaired wound healing. Various infection control methods and good surgical technique help in prevention. Diagnosis is done by physical examination and occasionally imaging. Emperic therapy directed at most likely pathogen, culture reports, wound class, prior antibiotics and resistance pattern. Wound care involves exploration, debridement, irrigation, dressing, NPWT and closure.

37. References Bailey and love, Texbook of Surgery Sabiston’s Text book of Surgery Swartz's text book of Surgery Hedrick TL, Sawyer RG, Friel CM, Stukenborg GJ. A method for estimating the risk of surgical site infection in patients with abdominal colorectal procedures. Dis Colon Rectum 2013; 56:627. Inui T, Bandyk DF. Vascular surgical site infection: risk factors and preventive measures. Semin Vasc Surg 2015; 28:201. Dias M, Dick A, Reynolds RM, et al. Predictors of surgical site skin infection and clinical outcome at caesarean section in the very severely obese: A retrospective cohort study. PLoS One 2019; 14:e0216157

38. Thanks