Increase in the rate of sternal surgical site infection after coronary artery bypass graft: a marker of higher severity of illness.
OBJECTIVE
To evaluate factors related to a gradual rise in sternal surgical site infection (SSI) rates.


METHODS
Retrospective cohort study.


METHODS
A 608-bed, tertiary care teaching hospital.


METHODS
All patients who underwent coronary artery bypass graft (CABG) from January 2000 through September 2004.


RESULTS
Of 3,578 patients who underwent CABG, 144 (4%) had sternal SSI. There was an increase in infection rate, with a marked reduction in the number of operations per year. The percentage of patients with peripheral vascular disease increased from 12% to 24.3% (P<.001), and the percentage with congestive heart failure increased from 17% to 22% (P<.001). Between 2002 and 2004, the mean duration of surgery increased from 233 to 290 minutes (P<.001), the percentage of patients with a National Nosocomial Infections Surveillance System (NNIS) risk index of 2 increased from 14.3% to 38% (P<.001), and the percentage of patients with a postoperative stay in the intensive care unit of greater than 72 hours increased from 29% to 40.6% (P<.001). Multivariate analysis showed diabetes mellitus, peripheral vascular disease, obesity, duration of surgery, and postoperative stay in the intensive care unit of greater than 72 hours to be independently associated with infection.


CONCLUSIONS
An increase in infection in the CABG population not associated with an outbreak may be a reflection of a change in the severity of illness. Preoperative, intraoperative, and postoperative markers for increased infection risk may be used, in addition to the NNIS risk index, to assess the patient population risk.
Fakih
Mohamad G
MG
Division of Infectious Diseases, Department of Medicine, St. John Hospital and Medical Center, Grosse Pointe Woods, MI 48236, USA. mohamad.fakih@stjohn.org
Sharma
Mamta
M
Khatib
Riad
R
Berriel-Cass
Dorine
D
Meisner
Susan
S
Harrington
Steven
S
Saravolatz
Louis
L
D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003428:Cross Infection / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000517:prevention & control; D006764:Hospitals, Community / Q000706:statistics & numerical data; D006784:Hospitals, Teaching / Q000458:organization & administration / Q000706:statistics & numerical data*; D006786:Hospitals, Urban / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008485:Medical Audit; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D018571:Sentinel Surveillance; D012720:Severity of Illness Index; D013249:Sternum / Q000382:microbiology*; D013530:Surgical Wound Infection / Q000453:epidemiology* / Q000517:prevention & control; D013997:Time Factors
D000900:Anti-Bacterial Agents