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52 - PROPHYLACTIC ANTIBIOTIC USAGE AND PREDICTORS OF SURGICAL SITE INFECTION IN CLASS I GYNECOLOGIC SURGERY

052

PROPHYLACTIC ANTIBIOTIC USAGE ANDPREDICTORS OF SURGICAL SITE INFECTION IN CLASS I GYNECOLOGIC SURGERY

M. M. RIEGER1, O.LARA 2, K. R. SEBASTIAN 3, A. B. WHITE 4;
1Department of Women's Health, Dell Med. Sch. at TheUniv. of Texas at Austin, Austin, TX, 2UT Dell Sch. ofMed., Austin, TX, 3Seton Hlth.care Family, Austin, TX,4Univ. of Texas at Austin, Austin, TX.

Introduction: Surgical siteinfection (SSI) is a major cause of perioperative morbidity and posesa significant burden for healthcare systems.1-2Preoperative prophylactic antibiotics are commonly used to decreasethe risk of SSI. Widely accepted indications for preoperativeprophylactic antibiotics in gynecologic surgery include hysterectomyand procedures involving the use of mesh. However data is lacking toguide the use of antibiotic prophylaxis in class I gynecologicsurgery, that is - clean surgery in which the vagina, urinary, orgastrointestinal tract is not entered and in which a pre-existinginfection does not exist.3
Objective: We aimedto determine predictors of SSI among patients undergoing class Igynecologic surgery and which patients may benefit from preoperativeantibiotic prophylaxis.
Methods: After obtaining IRBapproval, we identified patients undergoing class I gynecologicsurgery at our institution between April 2011 and May 2015 by queryof CPT codes through our institution’s billing system and eachpatient’s chart was reviewed to confirm eligibility for inclusion.Procedures included were adnexal cystectomy, oophorectomy,salpingectomy, adnexal detorsion, myomectomy, lysis of adhesions, andexcision of pelvic mass. We collected patient demographic andperioperative data and built a multivariate logistic regression modelto determine predictors of SSI.
Results: 405 cases wereidentified for inclusion (325 laparoscopy, 80 laparotomy). Theoverall SSI rate was 2.96% (1.5% laparoscopy, 8.8% laparotomy).Patients undergoing laparotomy were significantly more likely to havereceived non-indicated preoperative antibiotics (p < 0.0001) andwere also more likely to be diagnosed with SSI (p = 0.0025). When allcases were considered, body mass index alone was a significantpredictor of SSI (OR 1.15, p < 0.001). In patients undergoinglaparotomy, American Society of Anesthesiologists (ASA) physicalstatus class greater than 1 was the single predictive factor of SSI(OR 24.53, p = 0.0092) and administration of preoperativeprophylactic antibiotics was protective against SSI (OR 0.03, p =0.0056). No factor was predictive of SSI in laparoscopy.
Conclusions:Patients undergoing class I laparotomy who do not receive antibioticprophylaxis are significantly more likely to be diagnosed with SSI,especially among patients with ASA class greater than 1. ASA classmay be a simple tool that can identify patients who would mostbenefit from preoperative antibiotics. Prospective trials are neededto confirm these findings.
References: 1. Curr ProblSurg. 2007; 44:635-675. 2. JAMA Surg. 2014; 149:575-581.3. ACOG Practice Bulletin, 104. 2014.

Table1. Patient Demographics


Laparoscopy(N=325)

Laparotomy(N=80)

PValue

Meanage ± SD, y

33.5± 10.2

37.5± 12.1

0.0025

MeanBMI ± SD, kg/m2

28.8± 7.27

29.8± 9

0.2710

Menopausal,n (%)

21(6.5%)

15(18.8%)

0.0009

Currentsmoker, n (%)

62(19.1%)

13(16.3%)

0.5600

Historyof diabetes mellitus, n (%)

13(4%)

5(6.3%)

0.3860

Historyof recent chemotherapy, n (%)

1(0.3%)

3(3.8%)

0.0291

ASAClassification, n (%)




1

100(30.8%)

16(20%)

0.0586

2

202(62.2%)

41(51.3%)

0.0758

3

21(6.5%)

23(28.8%)

<.0001

4

2(0.6%)

0(0%)

0.6103



Table2. Perioperative Outcomes

Variable

Laparoscopy(N=325)

Laparotomy(N=80)

PValue

Operativetime ± SD, minutes

52.2± 111.2

152.4±60.8

<.0001

Medianestimated blood loss (range), mL

25(5-2300)

100(5-3000)

<.0001

PerioperativepRBC transfusion, n (%)

8(2.5%)

19(24.1%)

<.0001

Occurrenceof significant anesthesia event, n (%)

0(0.0%)

4(5.0%)

<.0001

Mediantotal length of hospitalization, days (range)

1(1-8)

3(1-35)

<.0001

Preoperativeantibiotics given, n (%)

56(17.2%)

55(68.8%)

<.0001

SSIdiagnosed, n (%)

5(1.5%)

7(8.8%)

0.0025



Table3. SSI Diagnosis With and Without Antibiotics


Laparoscopy(N=325)




Laparotomy(N=80)




Antibiotics(N=56)

NoAntibiotics (N=269)

Pvalue


Antibiotics (N=55)

NoAntibiotics (N=25)

Pvalue

SSIDiagnosed, n (%)

0(0.0%)

5(1.9%)

0.3497


2(3.6%)

5(20.0%)

0.0311



Table4. Logistic Regression Model for Predictors of SSI

Variable

OddsRatio

95%CI

P-value

Laparotomy+ Laparoscopy




BMI

1.15

(1.08,1.21)

<.0001

Laparotomy




ASAScore

24.53

(2.21,272.84)

0.0092

Preoperativeantibiotics

0.03

(0,0.35)

0.0056