Ch. 10 Infections and Antimicrobials

Question 1

Six key risk factors identified in risk of surgical wound infections

Answer 1

1. duration of surgery
2. duration of anesthesia
3. surgical site preparation
4. method of wound closure
5. antimicrobial prophylaxis
6. comorbidities

Question 2

Criteria for a superficial surgical site infection

Answer 2

• within 30 days of operative procedure
• involves skin and/or SQ tissues of the incision
• one or more of the following: purulent drainage, bacteria aseptically cultured from the incision, diagnosis of a superficial incisional infection by the surgeon, heat/redness/painr OR localized swelling AND incision reopened by surgeon unless culture negative

Question 3

criteria for a deep surgical site infection

Answer 3

• within 30 days (90 for some procedures)
• deep soft tissues of the incision (fascia or muscle) affected
• one or more of: purulent drainage, spontaneous dehiscence of deeper incision OR incision is deliberately opened when patient has fever/localized pain OR tenderness UNLESS culture is negative

Question 4

criteria for organ/space surgical site infection

Answer 4

• within 30 days (90 for some procedures)
• any area other than the incision (skin, fascia, muscle) that was encountered during surgery
• one or more of: purulent drainage, bacteria, abscess or other evidence of infection on exam/reoperation/histo/imaging

Question 5

How does duration of surgery increase risk of infection

Answer 5

greater ability of bacteria to be exposed to and adhere within the surgical wounds
also may have more tissue desiccation

Question 6

How does duration of anesthesia increase risk of surgical site infection

Answer 6

no one true thing but anesthesia can lead to decreased body temp and impact the immune system

Question 7

how does surgical site preparation influence risk of surgical site infection

Answer 7

such as traumatic clipping, excessive scrubbing, clipping/shaving well in advance of surgery… might be skin trauma?

Question 8

how does the method of wound closure relate to risk of increased surgical site infection

Answer 8

not clearly demonstrated
skin staples were associated with an increased risk following stifle surgery in one retrospective but in another prospective, no difference between skin sutures and intradermal

Question 9

Name the anticipated bacteria and prophylactic antimicrobial for: skin and reconstructive surgery

Answer 9

staph –> cefazolin

Question 10

Name the anticipated bacteria and prophylactic antimicrobial for: elective orthopedic surgery

Answer 10

staph –> cefazolin

Question 11

Name the anticipated bacteria and prophylactic antimicrobial for: head and neck surgery

Answer 11

staph, strep, anaerobes –> clindamycin or cefazolin

Question 12

Name the anticipated bacteria and prophylactic antimicrobial for: thoracic and non GI abdominal surgery

Answer 12

staph –> cefazolin

Question 13

Name the anticipated bacteria and prophylactic antimicrobial for: open fractures

Answer 13

staph, strep, anaerobes –> cefazolin or clindamycin, +/- aminoglycoside or flouroquinolone

Question 14

Name the anticipated bacteria and prophylactic antimicrobial for: Upper GI surgery

Answer 14

gram positive cocci, enteric gram negative bacilli –> cefazolin

Question 15

Name the anticipated bacteria and prophylactic antimicrobial for: lower GI surgery

Answer 15

enterococci, gram negative bacilli, anaerobes –> cefoxitin

Question 16

Name the anticipated bacteria and prophylactic antimicrobial for: hepatobiliary surgery

Answer 16

Clostridium, gram negative bacilli, anaerobes –> cefoxitin

Question 17

Name the anticipated bacteria and prophylactic antimicrobial for: urogenital surgery

Answer 17

streptococcus, staph, e coli, anaerobes –> cefazolin or ampicillin

Question 18

What are the three strategies of the Surgical Care Improvement Project to administer prophylactic antibiotics

Answer 18

1. base antimicrobial selection on the pathogens expected to be present
2. ensure appropriate timing of the antimicrobial administration to ensure peak serum drug concentration at the time of first incision
3. discontinue the use of prophylactic antimicrobials within 24 hours post op

Question 19

What is the class and half life of cefazolin?

Answer 19

first generation cephalosporin

47 min –> that is why we redose every 90 min in surgery, we redose every two half lives

Question 20

What is the class and half life of ampicillin

Answer 20

penicillin

48 min

Question 21

What is the class and halflife of clindamycin

Answer 21

lincosamide

124-195 min (2-3 hours?)

Question 22

what is the class and half life of cefoxitin

Answer 22

second generation cephalosporin

40-60 min

Question 23

Description of a clean wound

Answer 23

non traumatic, uninfected
no break in aspetic technique
no inflammation encountered
primarily closed, elective, no drains

Question 24

description of a clean contaminated wound

Answer 24

controlled entry into a hollow viscus organ, minor break in aseptic technique

Question 25

description of a contaminated wound

Answer 25

open, fresh traumatic wound, incision into a site with acute non purulent inflammation, major break in aseptic technique

Question 26

description of a dirty wound

Answer 26

pus encountered, perforated viscus organ, traumatic wound with devitalized tissues/foreign material/fecal contamination/older than 4 hours, acute bacterial infection