Surgical wound infection

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Surgical site infection ( post-operative wound infections, English surgical site infections , SSI) are infections after a surgical intervention ( operation ) in the area of the wound can occur.

frequency

For 2006, 255,000 surgical wound infections were estimated in German acute hospitals. They are the most common with a share of 24% nosocomial infections , ahead of urinary tract infections by catheterization , pneumonia related to ventilators and blood stream infections through catheters . There is no obligation to report or precise registration in Germany.

In comparison, 18 million inpatient treatments and 51 million surgical interventions and invasive procedures were carried out in German acute hospitals in 2012. The SSI rates depend largely on the type, duration, location and urgency of the procedure, the patient's risk profile and the hygienic conditions.

Contamination levels

Operations are divided into four degrees or classes of contamination , depending on the pre-existing contamination of the region to be operated on, with an increasingly higher risk of surgical wound infection. They are a gradation of the contamination of the operating area.

  • Grade I : interventions in non-contaminated regions, e.g. B. joint and bone operations, arthroscopic interventions, soft tissue operations on the trunk and extremities without contact with colonized organs and tissues, organ transplants without contact with colonized organs or tissues, heart and vascular operations, neurosurgical operations.

The levels of contamination are in connection with the ASA score used and the procedure time to reduce the risk for surgical site infection to identify (surgical site infections, SSI). The original classification system was developed in 1964 by the National Academy of Sciences and the Cooperative Research Study of the National Research Council and modified by the CDC in 1982 . The use of the classification is controversial, the predictive benefit of the classification for the risk of SSI is questioned.

According to the current recommendation of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) by Robert , a separation of operating theaters according to contamination classes (especially " septic ", i.e. grade IV vs. " aseptic "), which was common in the past and is still required today by the professional associations Koch Institute does not make sense, as there is so far no evidence that such a separation reduces the risk of surgical wound infections.

Etiopathogenesis

The germs that get into a surgical wound during a surgical procedure or an invasive procedure come in the majority of cases from the patient himself (endogenous infection) and less often from the operating staff or the material used (exogenous infection).

The most common source of endogenous infection is the germ colonization in the region to be operated on. The surgical procedure removes the natural body barriers mechanically (e.g. severing the colon during an operation for colon cancer); at the same time, the patient's immune system is weakened by the procedure.

In addition, in the case of endogenous infections, germs from other regions of the patient's body can also get into the wound; this applies in particular to the most common germ of wound infection, Staphylococcus aureus and its multi-resistant form MRSA, which are often found in the patient's nose, but also for the patient's own bacterial flora (especially in the intestines , on the skin or in the respiratory tract ). Therefore, in planned ("elective") interventions, screening with a nasal swab and possibly with decontamination is often carried out beforehand .

Most pathogens causing surgical wound infections are bacteria. The most common are Staphylococcus aureus , coagulase-negative staphylococci , Enterobacteriaceae , enterococci and anaerobes . Mushrooms such as B. Candida albicans can also be causative. Mixed infections are common.

The following risk factors may be present on the patient side (dispositional risk factors): old age, immunosuppression (reduced body's own defenses, proven connection e.g. for HIV infection , kidney transplantation or colorectal carcinoma ), concomitant diseases such as B. diabetes mellitus , infections or colonization with certain germs (e.g. Staphylococcus aureus ), obesity or a body mass index (BMI) of over 25 or 30, smoking, anemia and preoperative malnutrition .

Operational factors also contribute to the risk of postoperative wound infection . These include B. the type of hair removal before the operation, the degree of contamination of the surgical procedure, the skin disinfection of the operating area, the duration of the operation and the hygienic behavior of the operating staff. High blood loss and / or an intraoperative blood transfusion can also promote wound infection.

Both the incidence of postoperative wound infections and the spectrum of pathogens depend on the type of intervention and are very different in the various surgical disciplines ( for example, significantly higher infection rates in abdominal surgery than in ophthalmic surgery).

Clinical picture

Wound infections typically occur a few days after an operation, and late infections several weeks after an operation are also possible. With superficial wound infections, the cardinal symptoms of inflammation are found on the skin and subcutaneous tissue : reddening of the wound edges, overheating, tenderness to pressure, swelling, impaired wound healing with (foul-smelling) exudation . A fever can also occur. The development of an abscess (encapsulated inflammation with pus formation) or a phlegmon (diffuse inflammation that penetrates the tissue) are possible (purulent or pyogenic inflammation). There may be a wound dehiscence come. Necrotizing fasciitis or abscesses can develop in deeper layers, purulent peritonitis ( abdominal cavity ) or pleural empyema (thorax) in the area of ​​the large body cavities , and osteomyelitis can develop on the bones and joints .

If foreign material ( joint prostheses , synthetic meshes, etc.) is embedded, prosthesis or mesh infections can occur, sometimes as late infections. However, these can also be triggered by a later colonization of germs, by spreading of germs via the bloodstream ( hematogenous ), which is why a prophylactic antibiotic administration is carried out in the case of interventions in contaminated regions with existing implants.

Classification

In 1999, the Centers for Disease Control and Prevention (CDC) published an internationally recognized classification for surgical wound infections. It distinguishes between three grades:

Category A1 (post-operative superficial wound infection)

The following criteria must be met:

  • Infection at the skin incision site within 30 days of surgery involving only skin or subcutaneous tissue
  • One of the following criteria:
    • purulent secretion from the superficial incision
    • cultural evidence of pathogens from the wound
    • any of the following: pain or tenderness, swelling, redness, or warmth and the surgeon deliberately opening the superficial incision. This criterion does not apply in the presence of a negative microbiological culture of the superficial incision.
    • Diagnosis of the attending physician

Category A2 (postoperative deep wound infection)

The following criteria must be met:

  • Infection within 30 days of surgery
  • Infection appears to be related to the surgery
  • Captures the fascia layer and muscle tissue
  • One of the following criteria applies:
    • purulent secretion from the depth of the incision,
    • spontaneously or consciously opened by the surgeon,
    • Abscess or other signs of infection in the deeper layers

Category A3 (infections of organs and body cavities in the operating area)

The following criteria must be met:

  • Infection within 30 days of surgery
  • Infection appears to be related to the surgery
  • Detects organs or body cavities that were opened during surgery or that have been manipulated
  • One of the following criteria applies:
    • purulent secretion from a drain that has access to the organ or the body cavity
    • cultural pathogen detection
    • Abscess or other signs of infection of the organ or body cavity

therapy

The treatment of postoperative wound infections, depending on the type, extent and pathogen, is either conservative with antibiotic treatment (e.g. in the case of a phlegmon), antiseptic dressings and cooling, or surgically (opening the wound, splitting abscess or surgical revision with irrigation, debridement , drainage insert or removal of any foreign material).

However, surgical wound infections represent an emergency and a wait-and-see behavior can lead to an expansion of the infection, wound necrosis , wound dehiscence and septicemia and sepsis , which is why, apart from superficial minor wound infections, an early surgical revision is often sought. Often drains have to be left in place, or an open wound treatment is carried out without skin closure so that further secretion can drain off. Secondary wound healing must then often be awaited. In certain cases, the wound can be sutured again after the wound base / edges have been conditioned, e.g. B. after a vacuum sponge therapy . For larger wound defects, plastic interventions with skin grafts or skin flaps are sometimes necessary.

Chronic infections can develop, especially in the case of infections of deeper structures, especially on the bones as chronic bone marrow inflammation .

If implants are in place, such as knee or hip endoprostheses , these must be removed in the event of severe infections. Depending on the severity of the infection and local practice, a new prosthesis is then implanted directly ("one-step procedure") or weeks to months after the wound has been repaired ("two-step procedure"). A bone cement spacer with an antibiotic (often refobacin ; also vancomycin ) can be used temporarily .

Even with osteosynthesis material to stabilize a broken bone , this usually has to be removed if the wound is deeply infected. Then a "change of procedure" to a different type of osteosynthesis is often carried out, e.g. B. from a plate osteosynthesis change to an intramedullary nail . In the case of severe infections, an external fixator can also be used, the wires of which are inserted into the bone outside the infected area. This is also the procedure of choice for open and primarily heavily contaminated multifragment fractures (e.g. open tibia fractures). In neurosurgery , skull plate implants must also be removed if there is a deep wound infection.

Prevention

An early (enteral) diet reduces the risk of SSI, as does good control in the case of existing diabetes mellitus . Tobacco and alcohol abstinence and weight loss also have a protective effect. Pre- existing anemia should be treated.

In order to avoid and reduce the occurrence of surgical wound infections, the recommendations of the KRINKO must be observed on the basis of the Infection Protection Act (recommendation for the prevention of postoperative wound infections ). The following are a selection of essential recommendations, e. In some cases, abbreviated and modified:

Pre- / intraoperative measures

It is recommended:

  • As far as possible, to identify and treat existing infections in the patient preoperatively (Cat. IB).
  • to decolonize Staphylococcus aureus with a nasal ointment and body wash during certain operations
  • Before colorectal operations, a mechanical emptying of the bowel in connection with oral antibiotics should be performed (Cat. II).
  • Hair in the operating area can be removed by shortening the hair and not by shaving (Cat. IA).
  • Operating theater staff: take off all outer clothing including shoes and put on area clothing (e.g. pants, shirt / gown , operating theater shoes) that is low in germs (prepared in the disinfection washing process) in the clean area after hygienic hand disinfection (cat. II). Do not wear jewelery, rings or watches on forearms or hands (Cat. II) or other dangerous pieces of jewelery, as well as long or artificial fingernails and no nail polish (Cat. IB).
  • Put on mouth and nose protection (MNS) and hair protection (Cat. IB).
  • to use pharmaceutically approved alcohol- based preparations as the means of choice for surgical hand disinfection (Cat. IB);
  • sterile surgical gowns, sterile disposable gloves (Cat. IB). For operations that experience has shown to be associated with increased glove lesions, two pairs of gloves should be worn (Cat. II). Change gloves immediately before implanting a joint endoprosthesis (Cat. II).
  • in the operating room, a thorough antisepsis carry out the skin of the operation area with an alcohol-based skin antiseptic (Cat. IA). The addition of a remanent antiseptic achieves a lasting effect beyond the effects of alcohol (Cat. IB). To keep the skin area saturated and moist during the declared exposure time, preferably by applying the antiseptic several times. Pay attention to the longer exposure time on skin areas rich in sebum glands (Cat. II).
  • after the antisepsis of the operating area, to cover the area around the operating area in a sterile manner (Cat. IB)
  • during the operation to limit the number of people present in the operating room, to limit their fluctuation and their speaking to a minimum, to keep the doors of the operating room closed as far as possible (Cat. II).
  • the indication for systemic antibiotic prophylaxis specific to the procedure (Cat. IA). Carry out multiple doses during the operation only for very long operations (Cat. IA). Refrain from prolonged antibiotic administration after the end of the operation (Cat. IA).
  • specify the use of skin protection and skin care products in the skin protection plan (cat. II / IV).

Post-operative measures

It is recommended

  • cover the surgical wound with a sterile wound pad at the end of the operation . The first dressing change should be carried out after about 48 hours, unless there are indications of a complication for an earlier dressing change (Cat. IB). If the wound is then dry and closed, a renewed sterile wound covering can be dispensed with under hygienic aspects (Cat. IB). Regular medical inspection of the wound is part of a complete and proper follow-up care . Remove drains (from a hygienic point of view) as early as possible (Cat. II); the time of removal is surgically determined.
  • In addition to providing the patient with the necessary information about the risks associated with the operation, providing basic information about the possibilities to prevent an SSI through hygiene- conscious action and timely information about a deviating healing process (Cat. II).
  • It is not necessary to use different dressing trolleys for aseptic and infected wounds - it is crucial to protect the trolley from contamination .

Spatial and technical design of the operating room

It is recommended:

  • if instrument tables are not prepared in the operating room , but in a separate room (preparation room for instrument tables ), the same hygienic conditions (e.g. ventilation conditions) as in the operating room must be ensured there.
  • to separate the clean and unclean sides at least functionally in the staff changing room.
  • The recovery structurally preferably at the transition from the surgery department with the rest of the hospital to place and to counteract by functional and organizational measures of an opening of the principle of personal lock.
  • to reserve a room or zone for the material supply where the goods are delivered without transport packaging. A separate waste disposal room should be kept available for disposal.
  • The hygienic requirements for the spatial design of surgical departments depend on the task at hand. Adequate room planning facilitates sensible process organization and ensures that, with sufficient space, hygienically perfect work is possible for all operations (regardless of their technical assignment and degree of contamination), taking into account the respective medical equipment and personnel costs. Zoning is recommended for operating theater departments with very different levels of service.
  • Triple- filtered air is introduced into the operating rooms (and, if necessary, preparation rooms for setting up instrument tables) . The operating theaters have overpressure maintenance compared to the adjoining rooms.
  • Operations with a low SSI risk can be carried out under modified spatial conditions. A low risk of infection is z. As given in small operations on the skin / subcutaneous tissue , the eye , in the mouth - maxillary , frontal sinus , endoscopies of body cavities , abscess opening and for interventional radiology and cardiology procedures (except with regular adhesive expected change of procedure (...)) yet The risk of infection is lower with tumors or foreign bodies lying at the skin level (except when very extensive) and with injuries to the skin or the subcutis (except when very extensive). These invasive measures can also be carried out in a room that is not integrated into an operating theater department.
  • The question of whether an operation is performed on an “ outpatient ” or “ inpatient ” basis does not play a role in assessing the SSI risk.

Individual evidence

  1. ↑ a b c d RKI: Prevention of postoperative wound infections. (PDF) Recommendation of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute, accessed on August 19, 2019 .
  2. ↑ Petra Gastmeier , C. Geffers: Nosocomial Infections in Germany: How Many Are There Really? In: DMW - German Medical Weekly . tape 133 , no. May 21 , 2008, ISSN  0012-0472 , p. 1111-1115 , doi : 10.1055 / s-2008-1077224 .
  3. ↑ a b KRINKO: Hygiene requirements for operations and other invasive procedures . Robert Koch Institute, April 1, 2000, doi : 10.25646 / 162 ( rki.de [accessed on August 8, 2019]).
  4. ↑ a b Ikemefuna Onyekwelu, Ramakanth Yakkanti, Lauren Protzer, Christina M. Pinkston, Cody Tucker: Surgical Wound Classification and Surgical Site Infections in the Orthopedic Patient: . In: JAAOS: Global Research and Reviews . tape 1 , no. 3 , June 2017, ISSN  2474-7661 , p. e022 , doi : 10.5435 / JAAOSGlobal-D-17-00022 , PMID 30211353 , PMC 6132296 (free full text) - ( ovid.com [accessed August 8, 2019]).
  5. ↑ Mila H. Ju, Mark E. Cohen, Karl Y. Bilimoria, Melissa S. Latus, Lisa M. Scholl: Effect of Wound Classification on Risk Adjustment in American College of Surgeons NSQIP . In: Journal of the American College of Surgeons . tape 219 , no. 3 , February 2014, p. 371–381.e5 , doi : 10.1016 / j.jamcollsurg.2014.04.009 , PMID 25053222 , PMC 4143469 (free full text) - ( elsevier.com [accessed August 8, 2019]).
  6. ^ Shauna M. Levy, Kevin P. Lally, Martin L. Blakely, Casey M. Calkins, Melvin S. Dassinger: Surgical Wound Misclassification: A Multicenter Evaluation . In: Journal of the American College of Surgeons . tape 220 , no. 3 , March 2015, p. 323–329 , doi : 10.1016 / j.jamcollsurg.2014.11.007 ( elsevier.com [accessed August 8, 2019]).
  7. ↑ Prevention of post-operative wound infections . In: Federal Health Gazette - Health Research - Health Protection . tape 61 , no. 4 , March 27, 2018, ISSN  1436-9990 , p. 448-473 , doi : 10.1007 / s00103-018-2706-2 .
  8. ↑ Peter Bischoff Petra Guest Meier: The Separation of Septic and Aseptic Surgical Areas is Obsolete . In: Deutsches Aerzteblatt Online . July 10, 2017, ISSN  1866-0452 , doi : 10.3238 / arztebl.2017.0463 , PMID 28764833 , PMC 5545628 (free full text).
  9. ↑ Ford CD, VanMoorleghem G, Menlove RL: Blood transfusions and postoperative wound infection . In: Surgery . S. 113 (6): 603-607 .
  10. ^ A b World Union of Wound Healing Societies (WUWHS). Best Practice Principles: Wound Infections in Clinical Practice. An international consensus. London: MEP Ltd, 2008. Available at www.mepltd.co.uk . 2008.
  11. ↑ Sandra I. Berríos-Torres, Craig A. Umscheid, Dale W. Bratzler, Brian Leas, Erin C. Stone: Centers for Disease Control and Prevention Guideline for the Prevention of Surgical Site Infection, 2017 . In: JAMA Surgery . tape 152 , no. 8 , August 1, 2017, ISSN  2168-6254 , p. 784 , doi : 10.1001 / jamasurg.2017.0904 .
  12. ↑ Elisabeth Maurer, Alexander Reuss, Katja Maschuw, Behnaz Aminossadati, Thomas Neubert: Superficial surgical site infection following the use of intracutaneous sutures versus staples — a randomized single-center trial in an elective gastrointestinal surgery setting . In: Deutsches Aerzteblatt Online . May 24, 2019, ISSN  1866-0452 , doi : 10.3238 / arztebl.2019.0365 , PMID 31315799 , PMC 6647811 (free full text).