Surgical Site Infection

ByDoctor Saleem

surgical site infections3rd most common nosocomial infection 14-16% Most common nosocomial infection among surgery patients 38% 2/3 incisional 1/3 organ

Important DefinitionsColonization

Bacteria present in a wound with no signs or symptoms of systemic inflammation

Usually less than 105 cfu/mLContamination

Transient exposure of a wound to bacteriaVarying concentrations of bacteria possibleTime of exposure suggested to be < 6 hoursSSI prophylaxis best strategy

Contd;Infection

Systemic and local signs of inflammationBacterial counts ≥ 105 cfu/mLPurulent versus nonpurulent

Surgical wound infection is SSI

Criteria for defining SSIs

Further ClassificationEtiology a) Primary The wound is the primary site of infection b)Secondary Infection arises following a complication

that is not directly related to wound

Contd;Time a) Early Infection presents within 30 days of

procedure b) Intermediate Occurs between one and three months c) Late Presents more than three months after

surgery

Contd;Severity a) Minor Wound infection is described as minor

when there is discharge without cellulitis or deep tissue destruction

b) major When there is pus discharge with tissue

breakdown , Partial or total dehiscence of the deep fascial layers of wound or if systemic illness is present.

Wound assesmentFor surgical wound assesment several

scoring systems are employed especially a) Asepsis scoring b) Southampton wound assessment scale These enable surgical wound healing to be

graded according to specific criteria, usually giving a numerical value, thus providing more objective assessment of wound.

Microbiology

Lactobacilli

StreptococciLactobacilli

Enterobacteriaceae

Aerobic+

AnaerobicMicrobial

Populations

Pathogenesis

VirulenceBacterial dose

Impairedhost resistance

Risk factorsPatient factorsDiabetes ObesityNicotine use Steroid use MalnutritionHospital stay Nares colonization with S. aureus Transfusion

Diabetes Controversial Patients underwent CABG @ Increasing levels of HbA1c and SSI rates @ Increased glucose levels (>200 mg/dL)

Nicotine use Delays primary wound healing Increase the risk of SSI

Steroid use Controversial

Malnutrition Theoretical arguments: increase the SSI risk Two randomized clinical trials: preoperative “nutritional therapy” did not reduce incisional

and organ/space SSI risk.

Prolonged preoperative hospital stayPreoperative nares colonization with S.

aureus Mupirocin ointment: Controversial

Perioperative transfusion No scientific basis

Preop factors Preoperative antiseptic showering Preoperative hair removal Patient skin preparation in the operating

room Preoperative hand/forearm antisepsis Antimicrobial prophylaxis

Preoperative antiseptic showering Decreases skin microbial colony counts No evidance of benefit to reduce SSI rates

Preoperative hair removal Shaving: @ immediately before the operation: SSI rates

3.1% @ shaving within 24 hours preoperatively: 7.1% @ having performed >24 hours: SSI rate > 20%. Depilatories: @ lower SSI risk than shaving or clipping @ hypersensitivity reactions

Patient skin preparation in the operating room Most common used: Alcohol solutions Chlorhexidine gluconate Iodophors

Preoperative hand/forearm antisepsis

Prophylactic antibioticsClass 1 = CleanClass 2 = Clean contaminatedClass 3 = ContaminatedClass 4 = Dirty infected

Prophylactic antibiotics indicated

Therapeutic antibiotics

WoundClassification

Antibiotic PCN Allergy

I 1st generation Cephalosporin

Vancomycin Clindamycin

II-Biliary,GU, Upper Digestive

1st generation Cephalosporin

Vancomycin Clindamycin

II-Distal Digestive

2nd generation Cephalosporin

Aztreonam and Clindamycin/Flagyl

III/IV Generally Therapeutic

ABX

Once the incision is made,antibiotic delivery to thewound is impaired.Must give before incision!

Operative characteristics Operating room environment Surgical attire and drapesAsepsis and surgical technique

Operating room environment Ventilation

@ Positive pressure with respect to corridors and adjacent areas

Environmental surfaces @ Rarely implicated as the sources of pathogens important in the development of SSIs. @ Important to perform routine cleaning of these

surfaces Conventional sterilization of surgical instruments @ Inadequate sterilization of surgical instruments has resulted in SSI outbreaks

Surgical attire and drapes The use of barriers: @ patient: minimize exposure to the skin, mucous membranes, or hair of surgical team members @ surgical team members: protect from exposure to blood and bloodborne pathogens.

Asepsis and surgical technique Rigorous adherence to the principles of asepsis by all

scrubbed personnel Excellent surgical technique: reduce the risk of SSI. Drains: increase incisional SSI risk.

Postoperative issuesIncision care

The type of postoperative incision care @ closed primarily: the incision is usually covered with a sterile dressing for 24 to 48 hours. @ left open to be closed later: the incision is

packed with a sterile dressing. @ left open to heal by second intention: packed

with sterile moist gauze and covered with a sterile dressing.

Treatment surgical site infection Efflux of purulent material and pus Fascia is intact: debridement Irrigated with N/S and packed to its base with saline-moistened gauze Fascia separated: drainage or reoperation Most SSIs: healing by secondary intention

Discharge planning The intent of discharge planning: maintain integrity of the healing incision, educate the patient about the signs and symptoms of infection, advise the patient about whom to contact to report any problems.