Lecture 1: Aseptic technique and surgical site infection Flashcards
Difference between prophylactic antibiotic and therapeutic antibiotic
Prophylactic given before contamination or infection, therapeutic given to combat existing infection
define contamination
presence of microorganisms on a surface, not invading tissue
define infection
invasion and replication of microorganisms within tissue- causing pathological issue
define antiseptic
substance that prevents or arrests growth of microorganisms, substance is applied to living tissue
Define asepsis
prevention of contact with microorganisms
define disinfectant
chemical or physical agent that destroys microorganisms but not spores, substance is applied to inanimate objects, decreases microorganism load
define sterilization
process used to render a product free of all microorganisms (instruments)
what is surgical site infection
infection that occurs after surgery in part of the body where surgery took place
why do we care about infection
increase patient morbidity (pain, inflammation, delayed healing), patient mortality, increased hospitalization, client dissatisfaction, increased cost
__% incidence of SSI infection across all surgical types
%5
__% infection in orthopedic procedures
7%
__% infection in dirty vs __% in clean procedures
18%, 2.5%
what are the 3 determinants of infection
- Microbial pathogens (level of virulence, # of pathogens)
- Local wound environment (necrotic tissue, absent skin barriers)
- Host defense mechanisms (immunocompromised, age)
what is the goal of aseptic surgery
reduce the level of bacteria in surgical wound to one that the patients immune system can control
What factors influence infection risk by either increasing microbes or decreasing immune system
- Duration of procedure
- Type of procedure
- Patient preparation
- Surgeon preparation
- Instrument sterilization
risk of infection __for every hour of surgery
doubles
Anesthesia longer than 4hrs infection risk increases by __% for each minute
2%
orthopedics surgery typically have higher incidence of infection due to __
implant/foreign object, increased risk for glove perforation, thermal necrosis
what surgical locations have higher incidence infection
anus, ear, digits
what is the description for clean surgery
Non-traumatic, elective, no acute inflammation, no break in aseptic technique, GI, GU, or resp tract not entered
what are some examples of clean surgeries
exploratory laparotomy, elective neuter, TPLO
what is the description for clean- contaminated surgery
- Controlled entry into GI, GU or resp
- Minor break in aseptic technique
- Clean wound with drain placement
what are some examples of clean contaminated surgeries
entertomy, cystotomy, hysterectomy
what is the description for contaminated surgery
fresh traumatic wounds <4hrs old, spillage from GI or UG tract, major break in aseptic technique
what are some examples of contaminated surgeries
bile spillage from cholecystectomy, lacerations
what is the description for a dirty/infected surgery
old traumatic wounds >4hrs old, devitalized tissue, perforated viscous encountered, purulent exudate, abscesses
what are some examples of dirty/infected surgeries
peritonitis from FB, ruptured gallbladder, bullae osteotomy for otitis media
patient is __source of microorganisms
endogenous
what causes the most wound infections
patients
what are the most common pathogens on skin
gram positive staphylococci, anaerobes, gram negative enteric near anus
what pathogens located in upper GI
gram + cocci, enteric gram - bacilli, anaerobes
what pathogens located in lower GI
enteric gram - bacilli, anaerobes
what pathogens located in urogenital tract
E. Coli, streptococcus, anaerobes
surgeons, instruments and OR preparation are __sources of microorganisms
exogenous
local wound environment has impact on ability of bacteria to __
establish infection
good blood supply to local wound allow recruitment of ___ and proper signaling to __
WBC, immune system
tissue trauma __# of bacteria required to produce infection
lowers
what things negatively affect local wound environemnt
- Surgical materials- act as FB
- Wound ischemia
- Surgeons technical skill
how do surgical materials negatively impact wound environment
harbor bacteria and shield them from host defenses
Bacteria produce biofilm that adheres to foreign material and protects bacteria
describe how biofilm protects bacteria
- Bacteria release proteins and polysaccharide molecules that adhere to implant
- Bacteria then adhere to this film via fibronectin
- Film protects bacteria from host and antibiotic defenses
how can shock/trauma cause increase risk for infection
decreased O2, change in pH, necrotic tissue= all support bacterial formation
What are halsted principles
- Minimize tissue trauma
- Control hemorrhage (hematoma= nidus for infection)
- Preserve blood supply
- Strict asepsis
- Minimize tissue tension
- Appose tissue accurately (maintains barriers)
- Eliminate dead space
what are the rules of aseptic technique
- Surgical members remain within sterile area
- Talking to minimum
- Non-scrubbed personnel do not reach over sterile field
- Scrubbed team members face each other and sterile field at all times
- If sterility of an item is question it is considered contaminated
- Sterile tables are sterile only at table height
- Gowns are sterile from mid-chest to waist and from gloved hand to 2 inches above elbow
