5 - Surgery Prophylaxis Flashcards

1
Q

Surgical site infection (SSI):
-Superficial or deep incisional or organ/space infection within _____ days of surgery or within ____ year if placement of prosthetic implant

A

30 days

1 year

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2
Q

SSI’s occur in ___% of surgeries

A

2

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3
Q

SSI’s account for __% of hospital-acquired infections

A

15

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4
Q

Significance of SSI’s?

A
  • increases hospital stay 7-10 days, readmissions 5x, mortality 2-3x
  • significant healthcare resources and cost
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5
Q

What are some patient-related risk factors for SSI’s?

A
  • advanced age, obesity, malnutrition
  • hypoxia associated with smoking or COPD
  • diabetes, perioperative hyperglycemia
  • immunocompromised
  • co-exisitng infection
  • colonization with resistant organism (ex. MRSA)
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6
Q

What are some surgery related risk factors for SSI’s?

A
  • operating room sterilization and ventilation
  • skin preparation
  • surgical equipment, personnel and technique
  • surgical wound classification
  • placement of foreign material ex. prosthetic implant, drain
  • thermoregulation, glucose control, O2 supplementation
  • duration of surgery
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7
Q

What is the most common pathogens in SSI’s?

A
  • S. aureus (20-30%)
  • Streptococcus (15-20%)
  • CoNS, most commonly S. epidermis (15%)
  • E. coli, Klebsiella, P. aeruginosa, Enterobacter (<10% each)
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8
Q

Goals of antimicrobial prophylaxis for surgery ?

A
  • reduce bacterial burden at incision site
  • prevent SSIs and associated morbidity, mortality & costs
  • minimize collateral resistance (ex. MRSA, ESBL, VRE)
  • avoid adverse effects including C. difficile
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9
Q

What % of SSI’s are preventable ?

A

50%

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10
Q

What are the optimal characteristics of an agents used as AP for surgery?

A
  • spectrum and bactericidal to cover most likely pathogens, but sufficiently narrow to minimize collateral resistance
  • pharmacokinetics to provide adequate tissue concentrations for duration of surgery from incision to closure
  • safety profile
  • low cost
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11
Q

List the key decisions in providing optimal AP for surgery

A

1) selecting an appropriate antimicrobial
2) selecting an appropriate dose (remember we are dosing to prevent an infection, not dosing to treat an infection)
3) optimizing timing of the preoperative dose, and re-dosing during surgery as required
4) using AP for the shortest effective duration

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12
Q

Describe when we should give surgery prophylaxis ?

A
  • the antibiotic should be given 1 hour before surgery
  • the best way of giving it is to do it with the anesthesia
  • if the antibiotic has a short half life or the surgery is really long, we may need to give another dose during surgery
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13
Q

Is continuing AP (antimicrobial prophylaxis) warranted?

A

no - usually unnecessary

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14
Q

AP for Head and Neck prophylaxis for clean with prosthesis placement

A

Cefazolin

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15
Q

AP for Head and Neck prophylaxis for clean-contaminated with mucosal incision (ex. cancer-related, radical dissection, trauma, reconstruction)

A

Cefazolin + Metro x < 24 hours

We add metro to cover anaerobes

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16
Q

AP for thoracic surgery

A

Cefazolin

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17
Q

AP for open heart surgery (CABG or valve replacement)

A

Cefazolin x < 24-48 hours

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18
Q

AP for cardiac device insertion (ex. pacemaker)

A

Cefazolin

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19
Q

AP for small intestine surgery (non-obstructed)

A

Cefazolin

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20
Q

AP for small intestine surgery (obstructed)

A

Cefazolin + Metro

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21
Q

AP for large intestine surgery

A

Cefazolin + Metro

(Avoid Cefoxitin - short half life, poor aerobic-anaerobic coverage

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22
Q

AP for biliary tract surgery (open)

A

Cefazolin

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23
Q

AP for biliary tract surgery

high risk laparoscopic

A

Cefazolin

24
Q

What would make a laparoscopic biliary tract surgery high risk ?

A
  • emergency
  • acute cholecystitis
  • prior biliary surgery < 1 month
  • stones
  • obstruction
  • prosthesis
  • over 70 yo
  • DM
  • pregnancy
  • IS
25
Q

AP for an elective C-section

A

Cefazolin

26
Q

AP for an emergency C-section

A

Cefazolin +/- Azithromycin

adding Azithro bc there tends to be atypical bacteria that can cause post-infections in women with C-sections

27
Q

AP for a hysterectomy (non-cancer related)

A

Cefazolin

28
Q

AP for a hysterectomy (cancer related)

A

Cefazolin + Metro

29
Q

AP for a hernia repair

A

Cefazolin

30
Q

AP for mastectomy that’s cancer related or high risk

A

Cefazolin

31
Q

AP for:

  • Lower tract urologic surgery that’s high risk
  • Upper tract urologic surgery
A

PO: Ciprofloxacin or TMP-SMX

IV: Cefazolin or Gent +/- Clindamycin

*goal here is to cover E. coli

32
Q

AP for open/laproscopic urologic surgery WITHOUT entry into GU tract

A

Cefazolin

33
Q

AP for open/laproscopic urologic surgery WITH entry into GU tract

A

Cefazolin +/- gentamycin

34
Q

AP for all vascular procedures

A

Cefazolin

35
Q

AP for Orthopedic joint replacement, implantation or fracture repair

A

Cefazolin +/- Gentamicin x < 24 hours

*adding Gent for more broad GN coverage

36
Q

AP for Orthopedic lower limb amputation

A

Cefazolin +/- Metro x < 24 hours

37
Q

When do we re-dose for AP?

A

every two half lives

38
Q

Preoperative dose and Half life for:

Azithromycin

A

500 mg IV

t1/2 = 70 hours
no re dosing required

39
Q

Preoperative dose and Half life for:

Cefazolin

A

2g IV or 3g IV for > 120 kg

t1/2 = 2 hours
re dosing every 4 hours

40
Q

Preoperative dose and Half life for:

Ceftriaxone

A

2 g IV

t1/2 = 8 hours

41
Q

Preoperative dose and Half life for:

Ciprofloxacin

A

400 mg IV or 500 mg PO

t1/2 = 4 hours

42
Q

Preoperative dose and Half life for:

Clindamycin

A

900 mg IV

t1/2 = 3 hours

43
Q

Preoperative dose and Half life for:

Gentamycin

A

3 mg/kg IV

t1/2 = 2 hours

44
Q

Preoperative dose and Half life for:

Metronidazole

A

500 mg IV

t1/2 = 8 hours

45
Q

Preoperative dose and Half life for:

TMP/SMX

A

160/800 mg PO

t1/2 = 8-11 hours

46
Q

Preoperative dose and Half life for:

Vancomycin

A

15 mg/kg IV

t1/2 = 8 hours

47
Q

Even if you haven’t hit 2 half lives, what would make you re-dose the antibiotic ?

A

-if blood loss > 1500 mL

48
Q

Re-dosing may not be required if prolonged t1/2 due to reduced _____ function

A

renal

49
Q

When would we use DW (dosing weight) ?

A

if > 130% of ideal body weight

50
Q

What is formula for DW?

A

DW = [ideal weight + 0.4 (actual weight - ideal weight)]

51
Q

What are the initiatives that improve the delivery of optimal AP for surgery within institutions?

A

1) Education
2) Standardizing AP guidelines including processes for timing of preoperative dose within 1 hour of incision, and re-dosing during surgery as required
3) Auditing and reporting performance, compliance and outcomes

52
Q

What are the benefits of AP for colorectal surgery?

A
  • SSI rate of 39% without AP versus 15% with AP
  • NNT = 5
  • postoperative mortality rate of 11.2% without AP versus 4.5% with AP
53
Q

What are the risk factors for SSI in the case on page 5 of the notes?

A
  • advanced age
  • diabetes
  • COPD
  • malnutrition
54
Q

Vancomycin covers MRSA whereas Cefazolin does not, so why don’t we use Vanco for AP?

A

-Vancomycin has a slower kill
and is not as effective for MSSA as Cefazolin

  • Cefazolin covers GN whereas Vanco has no GN
  • If we just gave every person Vanco, then there’s resistance to think about !!
  • Also, Vanco has to be slow infusion to prevent Red Man’s Syndrome
55
Q

Why is Clindamycin not a first line choice ?

A
  • high incidence of C dif

- no GN coverage

56
Q

Why would Cefoxitin be a poor choice for AP ?

A

SHORT HALF LIFE (45 mins)

  • would have to keep re dosing
  • not ideal