Lecture 13 9/27/24

Question 1

What is a clean operative wound?

Answer 1

non-traumatic, non-inflamed operative round in which the resp., GI, oropharyngeal, genital, and urinary tracts are not entered

Question 2

Which procedures fall into the clean category?

Answer 2

-exploratory laparotomy
-elective neuter
-total hip replacement
-fractures

Question 3

What is a clean-contaminated operative wound?

Answer 3

operative wound in which the resp., GI, oropharyngeal, genital, and/or urinary tract is entered in a controlled condition without unusual contamination

Question 4

Which procedures fall into the clean-contaminated category?

Answer 4

-enterotomy
-live fetus c-section
-laryngotomy

Question 5

What is a contaminated operative wound?

Answer 5

procedure in which GI contents or infected urine is spilled, or a major break in aseptic technique occurs

Question 6

Which procedure is an example of the contaminated category?

Answer 6

cystotomy with presence of infected urine

Question 7

What is a dirty operative wound?

Answer 7

procedure in which a viscus is perforated, or presence of purulent discharge or fecal contamination occurs

Question 8

Which procedures fall into the dirty category?

Answer 8

-excision of abscesses
-peritonitis
-bullae osteotomy for otitis media

Question 9

What should be done when contamination occurs during a surgical procedure?

Answer 9

-begin by using moisturized gauze sponges to remove gross contamination
-perform lavage
-remove lavage fluid and remaining contaminants with poole suction

Question 10

What is the bacteria count required for infection to occur?

Answer 10

10^5 bacteria per gram of tissue

Question 11

What is the risk of surgical site infection with each operative wound classification?

Answer 11

clean: 2 to 4.8%
clean-contaminated: 3.5 to 5%
contaminated: 4.6 to 12%
dirty: 6.7 to 18.1%

Question 12

What are the characteristics of a superficial incisional surgical site infection?

Answer 12

-occurs within 30 days of surgery
-infection of the skin or subcutaneous tissue

Question 13

What are the criteria for a superficial incisional surgical site infection?

Answer 13

-pain/tenderness, redness, heat, and/or localized swelling
-positive culture from aseptically obtained fluid from the wound
-purulent discharge

Question 14

What are the characteristics of a deep incisional surgical site infection?

Answer 14

-occurs within 30 days of surgery if no implant used
-occurs within 1 year of surgery if implant is present and infection relates to operation
-infection of the fascia or muscle

Question 15

What are the criteria for a deep incisional surgical site infection?

Answer 15

-localized pain/tenderness, redness, heat, and/or localized swelling
-fever
-purulent discharge
-deep abscess

Question 16

What are the characteristics of an organ/space surgical site infection?

Answer 16

-occurs within 30 days of surgery if no implant used
-occurs within 1 year of surgery if implant is present and infection relates to operation
-infection of any part of the anatomy other than the incision that was manipulated during the procedure

Question 17

What are the criteria for an organ/space surgical site infection?

Answer 17

-localized pain/tenderness, redness, heat, and/or swelling
-fever
-fluid accumulation
-purulent discharge

Question 18

What are the characteristics of deep and superficial SSI diagnosis?

Answer 18

-must distinguish between normal inflammatory reaction vs bacterial infection
-normal inflammation should resolve in 48 hours
-assess swelling, redness, and tenderness/pain
-assess serosanguineous and/or purulent discharge

Question 19

What are the systemic signs for all types of SSI?

Answer 19

-fever
-leukocytosis
-neutrophilia +/- left shift
-septic arthritis
-osteomyelitis
-peritonitis

Question 20

What are the patient-related factors for surgical wound infection?

Answer 20

-age
-body condition score/nutritional status
-co-morbidities
-altered immune system
-concurrent infection in a remote body system

Question 21

How can the incidence of SSI be limited?

Answer 21

-adequate preparation of the patient
-adequate preparation of the surgical team
-obedience to the Halsted principles of surgery
-judicious use of antimicrobials

Question 22

What are the Halsted principles?

Answer 22

-strict aseptic technique during prep. and surgery
-meticulous hemostasis
-obliteration of dead space
-minimize tissue trauma; careful handling
-preservation of blood supply
-avoid undue tension on tissue
-accurate tissue apposition

Question 23

What are the four main sources of bacteria in surgical site infections?

Answer 23

-environment/operating room
-surgeons
-instruments (only one that can truly be sterile)
-patients

Question 24

How can surgeons reduce the bacteria that they introduce to their patients?

Answer 24

-adequate scrubbing techniques
-appropriate use of cap, mask, and gloves
-appropriate gowning techniques/use

Question 25

How can bacterial contamination from surgical instruments be reduced?

Answer 25

-ensure everything used in surgery is sterile -follow the shelf life recommendations that go along with the product wrapping/packaging -use sterilization indicators

Question 26

Which steps can be taken to ensure patients do not infect their own wounds?

Answer 26

-large/wide clipped area -adequate draping

Question 27

Which foreign materials can be present in surgical sites?

Answer 27

temporary: -surgical drains -absorbable suture material permanent: -non-absorbable suture material -abdominal mesh -orthopedic implants

Question 28

What are the intrinsic risk factors for SSI?

Answer 28

-duration of surgery and anesthesia -type of surgery/cleanliness classification -presence of foreign material in the surgical site

Question 29

When are antimicrobials used in surgery?

Answer 29

-surgeries are high risk (not clean) -consequence of infection would jeopardize animal's life -estimated surgical time is longer than 90 minutes -prosthesis implantation is used

Question 30

When should pre-op antibiotics be administered?

Answer 30

-30 minutes to 1 hours before procedure if going IV -1 to 2 hours before if going IM

Question 31

Which bacteria are most likely to cause surgical infection?

Answer 31

ortho: Staphylococcus spp. GI: E. coli, polymicrobials, anaerobes cats: Pasteurella

Question 32

What are the potential side effects of antimicrobials used for surgical site infections?

Answer 32

-nephrotoxic -liver deficiency -pregnancy complications/metabolism by fetus

Question 33

What are the characteristics of prophylactic antimicrobials?

Answer 33

-delivered 30 minutes to 1 hour before surgical incision -ideally delivered IV -may be repeated every 1.5 to 2 hours depending on procedure length -discontinued immediately after closure or within 24 hours

Question 34

What are the characteristics of therapeutic antimicrobials?

Answer 34

-started after diagnosing SSI -ideally started immediately after obtaining sample for cytology and culture -therapy begins empirical -ideally given IV or PO in SA, IV/IM/PO in LA -initial treatment for 3-4 days, then reassess patient -duration of treatment varies with site of infection

Question 35

What is a nosocomial infection?

Answer 35

infection contracted during the hospitalization; absent at the time of admission

Question 36

What are the treatment steps for surgical wound infections?

Answer 36

-bacterial culture to identify pathogen and sensitivity -drainage and debridement of wound -cover wound with sterile bandage -judicious use of antibiotics

Question 37

What are the types of peritonitis?

Answer 37

-following a surgery --aseptic --septic -presence of free abdominal fluid

Question 38

What are the characteristics of medical management of peritonitis?

Answer 38

-stabilize the patient -patient typically in shock -hypoproteinemia, hypotension, hypoglycemia, and electrolyte imbalance common -IV crystalloids +/- plasma transfusion/colloids given -empirical, broad spectrum antimicrobials used

Question 39

What are the characteristics of surgical management for peritonitis?

Answer 39

-exploratory laparotomy -copious lavage -active or open abdominal drainage