PREVENTING WOUND INFECTION CHAPTER 8 PREVENTING WOUND INFECTION

Introduction Wound-a loss of continuity of skin or tissue that may have resulted due to a variety of reasons Primary wound closure Secondary wound closure Delayed primary closure (tertiary intention) Box 8.1 Stage 1 (0-3 days)-Inflammation Phases Stage 2 (2-5 days) Destructive Phase Stage 3 (3-24 days) Proliferation Phase Stage 4 (24 days-1year) Maturation phase

The Surgical Wound Account for many of the hospital acquired infections although many times not aware until after being discharged home. Most infections are acquired at time of procedure - most of the microorganism come from the patient’s own normal flora Potential sources of bacteria causing surgical site infection Patient-skin, colonized organ; Theater-staff, instruments, airborne particles; Ward-staff, dressings, airborne particles Factors that increase the risk of surgical site infection In the wound-number of bacteria, dead tissue, hematoma, tissue damage, foreign material In the patient-with malnourishment, obesity, underlying illness, immune deficiency, infection at a remote site

The Surgical Wound The possibility of an infection depends on the area of the procedure Intestinal procedures tend to have more infections because of the normal flora in the area Area where there is an infection already or that has necrotic tissue is more likely to result in a wound infection Staphylococcus epidermis can adhere to implanted material such as joint replacements and prosthetic heart valves where they multiply Other risk factors include age, underlying illnesses-such as diabetes. Immunosuppressive or steroid therapy also hinder healing. Poor nutrition and nicotine also can hinder healing.

Reducing the Risk of Surgical Site Infection Box 8.4 Key Elements for Minimizing the Risk of Surgical Wound Infections Short preoperative stay Disinfectant shower before operation Shaving kept to a minimum Contamination of the wound avoided-prepping skin with chlorhexidine or iodine Punctilious surgical technique Operation preformed quickly as is safe Scrupulous care in operations on the elderly, obese, malnourished or diabetic No drains brought out through the operative site Meticulous coagulation technique-dressing care-should be able to assess wound Information to each surgeon on his/her wound infection rate

Procedures in the Operating Department Ventilation and air filtration-many microorganisms on airborne particles Handwashing-microbicidal detergents or alcohol rubs are used to reduce the resident microbial flora of the skin and inhibit growth of bacteria. Hands and forearms should be scrubbed with antimicrobial soap for 2 to 5 minutes and then dried with sterile towels prior to donning surgical gloves. Operating room clothing-gowns ae made close woven and fluid resistant. Usually are disposable along with incision drapes. Masks are used to provide a barrier to splashes and droplets from the nose, mouth, and respiratory tract. Head covers may prevent bacteria from hair from entering the operative sites. Instruments and equipment-should be sterile; sterile packs can maintain sterility indefinitely, if they remain intact and not exposed to moisture, direct sunlight or heat

Procedures in the Operating Department Surfaces need to be cleaned everyday Room and surfaces need to be cleaned after every operation Large spill are cleaned with chlorine releasing granules Horizontal surfaces need to be cleaned at the beginning of the day to ensure dust is removed Minimum amount of equipment should be kept in operating room Equipment is cleaned each time being used prior to surgery

Surveillance of Surgical Site Infection Surgical site infections are important problem-delay recovery, increasing the length of hospital stay or may result in readmission Hospitals that had organized infection control programs showed a decrease in infections and these reports were shared The feedback from studies done about those programs showed doctors the importance of good surgical technique in preventing wound infections and was and is used to motivate change in practice where rates of infections are high

Definitions of Surgical Site Infections Superficial Incisional Infection-occurs within 30 days of surgery; involves the skin or subcutaneous tissue of the incision and meets one of the following: 1. Purulent drainage from the superficial incision 2. Superficial incision yields organisms from culture and sensitivity test 3. Signs of pain, tenderness, localized swelling, redness or heat Deep Incisional Infection Organ or Space Infection

Definitions of Surgical Site Infections Deep Incisional Infection-a surgical site infection involving the deep tissues that occurs within 30 days of operation if no implant and within 1 year if implant involved and one of the following: 1. Purulent drainage 2. Culture and Sensitivity shows growth of organism 3. Wound that dehisces or is deliberately opened by surgeon and has at least one symptoms or signs: fever, localized pain or tenderness, unless the incision culture is negative 4. An abscess or other evidence of an infection 5. Clinician’s diagnosis of deep incisional wound infection Organ or Space Infection

Definitions of Surgical Site Infections Organ or Space Infection-site other than the incision opened or manipulated during the procedure within 30 days of operation if no implant or 1 year if implant is in place; appears to be related to surgical procedure and meets at least one of the following: 1. Purulent drainage from a drain or stab wound into the organ or space 2. There is a culture and sensitivity report showing growth of microorganism 3. An abscess or other evidence of infection involving organ or space found by direct examination during reoperation or histopathological exam 4. Clinician’s diagnosis of organ/space wound infection

Management of Surgical Wounds Dressings placed on in the surgical room usually are not disturbed for 48 hours. This is done to allow the wound area to seal to keep bacteria from entering the wound. If dressing needs to be changed aseptic technique should be used After 48 hours dressing is removed and if wound is not draining then will be left exposed or protected with transparent dressing such as Opsite Patient is then able to shower or bathe if transparent dressing or site needs to be kept dry Some wounds continue to seep serous fluid and so they should be covered with sterile dressings. How often to change should be determined by provider or by amount of exudate. Site should be cleaned as ordered using sterile technique with sterile normal saline Drains should be attached to a sterile drainage bottle and changed as necessary, without touching connections and hands are washed thoroughly before and after procedure

Wounds Healing by Secondary Intention This term is used to describe the process of healing in wounds when there is tissue loss and there is a gap. This gap needs to heal by growing new tissue that fills the space from the inside out to the surface. These kind of wounds include ulcers, pressure sores, burns, and some surgical wounds where closure by suture is delayed such a dehisced wounds The formation of new granulation of tissue and microcirculation is encouraged by maintaining a moist environment at the bed of the wound because epithelial cells can only migrate in moist environment. It is also important to absorb excess moisture. Dressings such as alginates, hydrocolloids, and hydrogels are designed to absorb excess exudate while providing a moist environment to promote healing Exudate will lessen as the wound heals. Dressing needs to be assessed on a regular basis Removing the dressing excessively will hinder healing At times a wound may be cleansed with sterile fluid and an syringe Ischemic or necrotic tissue will delay healing, so that tissue will need to be removed by appropriate measures, this is known as debridement of wound Study Table 8.2 Features of Main Dressing Types for Chronic Wounds

Burns Infection remains the main cause of death amongst burn patients and in the burn ICU. Patients with large burns are particularly susceptible to sepsis because of the loss of the skin barrier, colonization of the wound surface by a variety or microorganisms, and the systematic effects of the immune system Pathogens encountered in burns may start as gram positive microorganisms but then change to gram negative which can cause the most severe infections in burn patients Treatment of full thickness burns mandates excision of the burn wound and covering with a skin graft or skin substitute. Reducing the time during which wound is exposed and has had a marked effect on incidence of infections associated with burns. Streptococcus pyogenes and Pseudomonas aeruginosa may interfere with skin grafting and cause an invasive infection that can become fatal.

Burns Partial thickness burns involve damage to deeper tissues such as blood vessels and nerves. These wounds are generally managed by using a variety of dressings. Evidence based studies have shown that hydrogel dressings, silicon coated nylon, silver containing dressings and biosynthetic dressings have shown a small but positive outcome. Silver sulfadiazine is a cream that is used to minimize the risk of wound infection in burn wounds for decades but has shown that can delay wound healing at times. Cross infection is a major problem on burn units. The main risk of transmission is on the hands of staff, but contaminated equipment has also been discovered to cause some infections Standard precautions and contact transmission precautions should be used when caring for a burn patient

Preventing Cross Infection Preventing the transmission of microorganisms from one patient to another patient is a particular problem with heavily colonized or infected wounds Bacteria transferred to clothing can be transferred from one patient to another so a clean disposable gown should be used for each dressing change Purpose of cleaning the wound is to remove excess exudate and necrotic tissue in order to minimize material that could support the growth of microorganisms that can cause infections Gentle cleaning with sterile saline or water is usually adequate, but cleaning fluids will be determined by physician Equipment needs to be cleaned appropriately before used on another patient Dressings with exudate needs to be discarded of appropriately in biohazard bags or containers. Gloves and plastic aprons or gowns should be used and discarded of appropriately. Creams and dressing materials should be used for one patient.

Detection and Treatment of Wound Infection Diagnosis of wound infection is based on the presence of clinical signs rather than the isolation of microorganisms from a swab. Surgical wounds should be inspected on a regular basis Detection of infection rely more on signs of inflammation spreading from the margins of the wound, local edema, reports of increasing pain in the wound or pyrexia with no signs of another infection being able to be diagnosed Purulent drainage will show better idea of organisms responsible for wound infection. In chronic wounds wound should be cleaned before collection of fluid is collected with a sterile swab