6. Surgical Infection and Use of Antibiotics

Question 1

18. Classification of surgical wounds and use of antibiotics

Answer 1

-Classification of surgical wounds:
>classified by degree of contamination-help predict likelihood of infection
>having more than 10^5 bacteria per gram of tissue-bacterial infection
>infection rate for all types of surgical wounds app. 5%
>4 categories:
1) clean: infection rate 0-6%, ABs not warranted, prophylactic ABs appear to be indicated in some clean procedures (orthopedic implants), given at induction (30-60min prior to incision), discontinued within 24h of procedure (at end of surgery), most likely postoperative infection-severe trauma with multiple fractures, traumatic procedures, orthopedic surgery or ovariansectomy

> prophylactic AB - (+/-), therapeutic AB -

2) clean-contaminated: minor break in aseptic technique, infection rate 4,5-9,3%, antimicrobial prophylaxis indicated, choice of AB based on anticipated flora, most likely postoperative infection > clean-contaminated fractures of pelvis and long bones (glove break-change gloves)

> prophylactic AB +, therapeutic AB -

3) contaminated: not infected initially, but have potential, infection rate 5,8-28,6%, antimicrobial prophylaxis indicated, choice of antibiotic based on anticipated flora, then modified according to culture and sensitivity results, most likely postoperative infection-contaminated fractures of pelvis and long bones; contaminated urogenital procedures, delicate debridement, copious lavage, antibiotic therapy-> clean wound, inadequate therapy->dirty wound*contamination present before surgery

> prophylactic AB +, therapeutic AB + = BOTH YES

4) dirty: gross infection present at time of surgical intervention, (traumatic wounds with retained devitalized tissue, foreign bodies, fecal contamination), antibiotic therapy, later modified according to culture and sensitivity results, copious lavage, debridement

> prophylactic AB -/+ (started earlier), therapeutic AB +

Question 2

18. Use of antibiotics

Answer 2

-ABs commonly misused (often based on tradition rather than on expected bacterial flora)
-AB resistance
-Prophylactic use: significant risk of infection, infection would be catastrophic
-Therapeutic use: ideally based on culture and susceptibility results, delay might be problematic
-some ABs are bacteriostatic at lower and bactericidal at higher concentrations-selection according to susceptibility

Question 3

Prophylactic use of antibiotics (ennaltaehkäisevä esim leikkauksen jälkeen, jotta infektio riski olisi pienempi)

Answer 3

-must be present at site during time of potential contamination
-not substitute for proper aseptic technique
-rational selection of AB: effective against at least 80% of probable pathogen
-Cefazolin (cefuroxime): no adverse effects on platelet aggregation, bleeding time, platelet size or count, prothrombin or activated partial thromboplastin time
-given 30-60 min i.v. before incision and discontinued within 24h (ideally at end of procedure)
> example: total hip replacement, open fracture repair, anal and rectal surgery, esophageal surgery

Question 4

Therapeutic use of antibiotics (käyttö kun on jo tulehdus/infektio eli hoito)

Answer 4

-based on clinical judgement, knowledge of ABs mechanism of action, microbiologic factors
-indicated in patients with: overwhelming systemic infection, when infection is present at surgical site or in body cavity, with any contaminated or dirty surgical procedure
-ideal dress is least toxic, kills bacteria at site of infection and does not negatively influence host immune system
-most surgical infections, AB therapy needs adjunctive therapy
-‘‘drugs of last resort’’ only if necessary

Question 5

19. Classification of surgical infections

Answer 5

1. primary=infection going to treat surgically in first place
2. complication = ex. ovariosectomy; not infected after surgery
3. support=IV catether long time not properly : immune system compromised
4. with prostethic implants

Question 6

20. Factors to be considered in order to prevent surgical infections

Answer 6

-ASEPSIS and ANTISEPTIC main goal prevent infections
-3 main categories: hat-related patient, virulence, amount of bacteria that cause disease
-factors to be considered: age, physical condition, nutritional status, diagnostic procedures, metabolic disorder, wound nature, operating room practice, bacterial contaminants, risk factors (overuse AB, advanced age)
>prevent: hospital envi and rational AB use