The timing of surgical antimicrobial prophylaxis.
OBJECTIVE
To obtain precise information on the optimal time window for surgical antimicrobial prophylaxis.


BACKGROUND
Although perioperative antimicrobial prophylaxis is a well-established strategy for reducing the risk of surgical site infections (SSI), the optimal timing for this procedure has yet to be precisely determined. Under today's recommendations, antibiotics may be administered within the final 2 hours before skin incision, ideally as close to incision time as possible.


METHODS
In this prospective observational cohort study at Basel University Hospital we analyzed the incidence of SSI by the timing of antimicrobial prophylaxis in a consecutive series of 3836 surgical procedures. Surgical wounds and resulting infections were assessed to Centers for Disease Control and Prevention standards. Antimicrobial prophylaxis consisted in single-shot administration of 1.5 g of cefuroxime (plus 500 mg of metronidazole in colorectal surgery).


RESULTS
The overall SSI rate was 4.7% (180 of 3836). In 49% of all procedures antimicrobial prophylaxis was administered within the final half hour. Multivariable logistic regression analyses showed a significant increase in the odds of SSI when antimicrobial prophylaxis was administered less than 30 minutes (crude odds ratio = 2.01; adjusted odds ratio = 1.95; 95% confidence interval, 1.4-2.8; P < 0.001) and 120 to 60 minutes (crude odds ratio = 1.75; adjusted odds ratio = 1.74; 95% confidence interval, 1.0-2.9; P = 0.035) as compared with the reference interval of 59 to 30 minutes before incision.


CONCLUSIONS
When cefuroxime is used as a prophylactic antibiotic, administration 59 to 30 minutes before incision is more effective than administration during the last half hour.
Department of General Surgery, University Hospital of Basel, Basel, Switzerland.
Walter P
WP
Weber
Walter R
WR
Marti
Marcel
M
Zwahlen
Heidi
H
Misteli
Rachel
R
Rosenthal
Stefan
S
Reck
Philipp
P
Fueglistaler
Martin
M
Bolli
Andrej
A
Trampuz
Daniel
D
Oertli
Andreas F
AF
Widmer
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019072:Antibiotic Prophylaxis / Q000592:standards*; D002444:Cefuroxime / Q000008:administration & dosage; D016009:Chi-Square Distribution; D002648:Child; D003428:Cross Infection / Q000453:epidemiology / Q000517:prevention & control; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008795:Metronidazole / Q000008:administration & dosage; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013530:Surgical Wound Infection / Q000453:epidemiology / Q000517:prevention & control*; D016896:Treatment Outcome
D008795:Metronidazole; D002444:Cefuroxime