Lecture 13 9/27/24 Flashcards
What is a clean operative wound?
non-traumatic, non-inflamed operative round in which the resp., GI, oropharyngeal, genital, and urinary tracts are not entered
Which procedures fall into the clean category?
-exploratory laparotomy
-elective neuter
-total hip replacement
-fractures
What is a clean-contaminated operative wound?
operative wound in which the resp., GI, oropharyngeal, genital, and/or urinary tract is entered in a controlled condition without unusual contamination
Which procedures fall into the clean-contaminated category?
-enterotomy
-live fetus c-section
-laryngotomy
What is a contaminated operative wound?
procedure in which GI contents or infected urine is spilled, or a major break in aseptic technique occurs
Which procedure is an example of the contaminated category?
cystotomy with presence of infected urine
What is a dirty operative wound?
procedure in which a viscus is perforated, or presence of purulent discharge or fecal contamination occurs
Which procedures fall into the dirty category?
-excision of abscesses
-peritonitis
-bullae osteotomy for otitis media
What should be done when contamination occurs during a surgical procedure?
-begin by using moisturized gauze sponges to remove gross contamination
-perform lavage
-remove lavage fluid and remaining contaminants with poole suction
What is the bacteria count required for infection to occur?
10^5 bacteria per gram of tissue
What is the risk of surgical site infection with each operative wound classification?
clean: 2 to 4.8%
clean-contaminated: 3.5 to 5%
contaminated: 4.6 to 12%
dirty: 6.7 to 18.1%
What are the characteristics of a superficial incisional surgical site infection?
-occurs within 30 days of surgery
-infection of the skin or subcutaneous tissue
What are the criteria for a superficial incisional surgical site infection?
-pain/tenderness, redness, heat, and/or localized swelling
-positive culture from aseptically obtained fluid from the wound
-purulent discharge
What are the characteristics of a deep incisional surgical site infection?
-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
What are the criteria for a deep incisional surgical site infection?
-localized pain/tenderness, redness, heat, and/or localized swelling
-fever
-purulent discharge
-deep abscess
What are the characteristics of an organ/space surgical site infection?
-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
What are the criteria for an organ/space surgical site infection?
-localized pain/tenderness, redness, heat, and/or swelling
-fever
-fluid accumulation
-purulent discharge
What are the characteristics of deep and superficial SSI diagnosis?
-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
What are the systemic signs for all types of SSI?
-fever
-leukocytosis
-neutrophilia +/- left shift
-septic arthritis
-osteomyelitis
-peritonitis
What are the patient-related factors for surgical wound infection?
-age
-body condition score/nutritional status
-co-morbidities
-altered immune system
-concurrent infection in a remote body system
How can the incidence of SSI be limited?
-adequate preparation of the patient
-adequate preparation of the surgical team
-obedience to the Halsted principles of surgery
-judicious use of antimicrobials
What are the Halsted principles?
-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
What are the four main sources of bacteria in surgical site infections?
-environment/operating room
-surgeons
-instruments (only one that can truly be sterile)
-patients
How can surgeons reduce the bacteria that they introduce to their patients?
-adequate scrubbing techniques
-appropriate use of cap, mask, and gloves
-appropriate gowning techniques/use
How can bacterial contamination from surgical instruments be reduced?
-ensure everything used in surgery is sterile
-follow the shelf life recommendations that go along with the product wrapping/packaging
-use sterilization indicators
Which steps can be taken to ensure patients do not infect their own wounds?
-large/wide clipped area
-adequate draping
Which foreign materials can be present in surgical sites?
temporary:
-surgical drains
-absorbable suture material
permanent:
-non-absorbable suture material
-abdominal mesh
-orthopedic implants
What are the intrinsic risk factors for SSI?
-duration of surgery and anesthesia
-type of surgery/cleanliness classification
-presence of foreign material in the surgical site
When are antimicrobials used in surgery?
-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
When should pre-op antibiotics be administered?
-30 minutes to 1 hours before procedure if going IV
-1 to 2 hours before if going IM
Which bacteria are most likely to cause surgical infection?
ortho: Staphylococcus spp.
GI: E. coli, polymicrobials, anaerobes
cats: Pasteurella
What are the potential side effects of antimicrobials used for surgical site infections?
-nephrotoxic
-liver deficiency
-pregnancy complications/metabolism by fetus
What are the characteristics of prophylactic antimicrobials?
-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
What are the characteristics of therapeutic antimicrobials?
-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
What is a nosocomial infection?
infection contracted during the hospitalization; absent at the time of admission
What are the treatment steps for surgical wound infections?
-bacterial culture to identify pathogen and sensitivity
-drainage and debridement of wound
-cover wound with sterile bandage
-judicious use of antibiotics
What are the types of peritonitis?
-following a surgery
–aseptic
–septic
-presence of free abdominal fluid
What are the characteristics of medical management of peritonitis?
-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
What are the characteristics of surgical management for peritonitis?
-exploratory laparotomy
-copious lavage
-active or open abdominal drainage
