Types of Wound Contamination and Minimising Surgical Infections

define bacterial infection

ore than 10^5 bacteria per gram of tissue

what is surgical site infection (SSI)

-infections of tissues, organs, or spaces exposed by surgeons during performance of an invasive procedure

what are SSIs classified into

-incisional infections (superficial and deep incisional)

-organ/space infections

SSIs result in

increased morbidity and mortality in surgical patients

surgical wounds classified by

degree of contam to help predict likelihood that infection will develop

-clean

-clean contaminated

-contaminated

-dirty

clean wounds

-non traumatic, non inflamed operative wounds in which respiratory, GI and oro-pharyngeal tracts are not entered

examples of clean wounds

•exploratory coeliotomy

•elective neuter

•total hip replacement

infection rate of clean wound

0-4.4%

clean contaminated wounds

-operative wounds in which resp, GI or genitourinary tract are entered under controlled conditions without unusual contam

-otherwise clean wound where drain placed

examples of clean contaminated wounds

•bronchoscopy

•cholecystectomy

•enterotomy

infection rate of contaminated clean wound

4.5-9.3%

contaminated wounds

-open, fresh, accidental wounds; procedures in which GI contents or infected urine spilled or major break in aseptic technique

examples of contaminated wounds

•cystotomy with spillage of infected urine

•open cardiac massage for CPR

infection rate of contaminated wound

5.8-28.6%

dirty wounds

-old traumatic wounds with purulent discharge, devitalised tissue or foreign bodies

-procedures in which viscus perforated or faecal contam occurs

examples of dirty wounds

•Examples:

•excision or drainage of an abscess

•bullae osteotomy for otitis media

•perforated intestinal tract

what is present in dirty wounds

gross infection present

host factors affecting infection rate

-age

-physical condition

-nutritional status

-diagnostic procedures

-concurrent metabolic disorders

-current meds

operating room practice to reduce infection

-aseptic technique

-sterilisation

-disinfection

-anaesthesia

-atraumatic technique

what methods are there for reducing infections

•Primary objective of aseptic surgery

•Host factors

•Operating room practice

•Characteristics of bacterial contaminants

how can patient prep reduce infections

•Clipping

•Scrubbing

•Draping

how can surgeon prep reduce infections

•Scrubbing

•Gowning

•Gloving

•Hats and masks

how can theatre behaviour reduce infections

•Etiquette

•Talking

•Flow etc

rationale use of antibiotics

-surgery time longer than 90 mins

-prosthesis implantation (mesh, pacemaker)

-pre existing prosthesis (hip replacement)

-severely infected or traumatised wounds

-rational selection for prophylactic use

-choice based on culture and sensitivity results

small animal antibiotics used i/v

-zinacef and augmentin pre surgery for gram pos

-surgery on LI needs metronidazole as anaerobic bacteria as well

why do you want to give antibiotics iv

gives highest circulating conc of antibiotic at time of contamination

i/v antibiotics horse

-fortified procane penicillin

-gentamicin

non i/v antibiotics in horses

engemycin LA