Preoperative Antibiotics (Anesthesia Text)


Timing of Preoperative Antibiotics

Prospective observational cohort study at Basel University Hospital, analyzed the incidence of SSI by the timing of antimicrobial prophylaxis in 3836 consecutive surgical procedures (single-shot administration of 1.5 g of cefuroxime plus 500 mg of metronidazole in colorectal surgery). 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 [Weber WP et. al. The timing of surgical antimicrobial prophylaxis. Ann Surg 247: 918, 2008]

Penicillin Allergies and Cross-Reactivity

(see excellent review by Pichichero [Pichichero ME. Pediatrics 115: 1048, 2005])
Of children who are reported to have a penicillin “allergy,” less than 10% have a true allergy. Rashes occur in 1-2.8% of cephalosporin administrations. While both PCN and cephalosporins have a B-lactam ring, in cephalosporins it is unstable a only transiently present in vivo. The clinical relevance of early tests of cross reactivity between PCN and cephalosporins (ex. hemagglutination inhibition, histamine release) has not been established. Skin tests have not confirmed cross-reactivity between these species. Over 25 studies have compared PCN and cephalosporin allergies – there may be an increased risk of allergic reaction to first generation cephalosporins, but this is based on data from the 1970’s in which Cephalosporium mold was used for PCNs, thus early 1st generations also contained PCN. There is no evidence for cross-reactivity to second, third, or fourth generation. Of note, PCN-allergic patients have a three-fold increased risk of allergic reactions to NON-cephalosporins. The risk of anaphylaxis to PCN is 0.0015-0.004%, and of cephalosporins is 0.0001-0.1%, but these are rough estimates [Pichichero ME. Pediatrics 115: 1048, 2005].

Infective Endocarditis

Highest-risk patients (ie prophylaxis IS indicated) include those with:
a. Presence of a prosthetic cardiac valve or prosthetic material
b. Previous IE
c. Unrepaired cyanotic congenital heart disease (including palliative shunts/conduits)
d. Completely repaired congenital heart defects with prosthetic material or device (surgical or percutaneous), within 6 mo. of the procedure
e. Repaired congenital heart disease with residual defects at the site, or adjacent to the site, of a prosthetic patch or prosthetic device (which inhibit endothelialization) – NO OTHER CHD!!!
f. Previous cardiac transplantation with subsequent cardiac valvulopathy (substantial leaflet pathology and regurgitation)
[Wilson et. al. Circulation 116: 1736, 2007]

New in 2007:

  • No BE prophylaxis for GI/GU procedures (ie: no abx solely to prevent BE)
  • BE prophylaxis for certain dental/airway/respiratory tract procedures or procedures involving infected skin, skin structures or musculoskeletal tissues only for “highest risk patients”
  • MVP, HOCM, Bicuspid AV do not require prophylaxis


PubMed search reveals no good data on duration to wait s/p pneumonia resolution prior to general anesthesia