Early-onset ventilator-associated pneumonia incidence in intensive care units: a surveillance-based study.

BACKGROUND: The incidence of ventilator-associated pneumonia (VAP) within the first 48 hours of intensive care unit (ICU) stay has been poorly investigated. The objective was to estimate early-onset VAP occurrence in ICUs within 48 hours after admission. METHODS: We analyzed data from prospective surveillance between 01/01/2001 and 31/12/2009 in 11 ICUs of Lyon hospitals (France). The inclusion criteria were: first ICU admission, not hospitalized before admission, invasive mechanical ventilation during first ICU day, free of antibiotics at admission, and ICU stay ≥ 48 hours. VAP was defined according to a national protocol. Its incidence was the number of events per 1,000 invasive mechanical ventilation-days. The Poisson regression model was fitted from day 2 (D2) to D8 to incident VAP to estimate the expected VAP incidence from D0 to D1 of ICU stay. RESULTS: Totally, 367 (10.8%) of 3,387 patients in 45,760 patient-days developed VAP within the first 9 days. The predicted cumulative VAP incidence at D0 and D1 was 5.3 (2.6-9.8) and 8.3 (6.1-11.1), respectively. The predicted cumulative VAP incidence was 23.0 (20.8-25.3) at D8. The proportion of missed VAP within 48 hours from admission was 11% (9%-17%). CONCLUSIONS: Our study indicates underestimation of early-onset VAP incidence in ICUs, if only VAP occurring ≥ 48 hours are considered to be hospital-acquired. Clinicians should be encouraged to develop a strategy for early detection after ICU admission.

Estimating attributable mortality due to nosocomial infections acquired in intensive care units.

BACKGROUND: The strength of the association between intensive care unit (ICU)-acquired nosocomial infections (NIs) and mortality might differ according to the methodological approach taken. OBJECTIVE: To assess the association between ICU-acquired NIs and mortality using the concept of population-attributable fraction (PAF) for patient deaths caused by ICU-acquired NIs in a large cohort of critically ill patients. SETTING: Eleven ICUs of a French university hospital. DESIGN: We analyzed surveillance data on ICU-acquired NIs collected prospectively during the period from 1995 through 2003. The primary outcome was mortality from ICU-acquired NI stratified by site of infection. A matched-pair, case-control study was performed. Each patient who died before ICU discharge was defined as a case patient, and each patient who survived to ICU discharge was defined as a control patient. The PAF was calculated after adjustment for confounders by use of conditional logistic regression analysis. RESULTS: Among 8,068 ICU patients, a total of 1,725 deceased patients were successfully matched with 1,725 control patients. The adjusted PAF due to ICU-acquired NI for patients who died before ICU discharge was 14.6% (95% confidence interval [CI], 14.4%-14.8%). Stratified by the type of infection, the PAF was 6.1% (95% CI, 5.7%-6.5%) for pulmonary infection, 3.2% (95% CI, 2.8%-3.5%) for central venous catheter infection, 1.7% (95% CI, 0.9%-2.5%) for bloodstream infection, and 0.0% (95% CI, -0.4% to 0.4%) for urinary tract infection. CONCLUSIONS: ICU-acquired NI had an important effect on mortality. However, the statistical association between ICU-acquired NI and mortality tended to be less pronounced in findings based on the PAF than in study findings based on estimates of relative risk. Therefore, the choice of methods does matter when the burden of NI needs to be assessed.

Early- and late-onset ventilator-associated pneumonia acquired in the intensive care unit: comparison of risk factors.

PURPOSE: To compare risk factors of early- (E) and late-onset (L) ventilator-associated pneumonia (VAP). MATERIALS AND METHODS: An epidemiological survey based on a nosocomial infection surveillance program of 11 intensive care units (ICUs) of university teaching hospitals in Lyon, France, was conducted. A total of 7236 consecutive ventilated patients, older than 18 years and hospitalized in ICUs for at least 48 hours, were studied between 1996 and 2002. Data during ICU stay, patient-dependent risk factors, device exposure, nosocomial infections occurrence, and outcome were collected. The cutoff point definition between E-VAP (six days) was based on the daily hazard rate of VAP. RESULTS: The VAP incidence rate was 13.1%, 356 (37.6%) E-VAP (within 6 days of admission) and 590 (62.4%) L-VAP were reported. Independent risk factor for E-VAP vs L-VAP was surgical diagnostic category (odds ratio [OR], 1.49 [95% confidence interval, 1.07-2.07]), whereas independent risk factors for L-VAP vs E-VAP were older age (OR, 1.01 [1.01-1.02]), high Simplified Acute Physiology Score II (OR, 1.01 [1.00-1.02]), infection on admission (OR=2.22 [1.61-3.03]), another nosocomial infection before VAP (OR, 5.88 [3.33-11.11]), and exposure to central venous catheter before VAP (OR, 4.76 [1.04-20.00]). CONCLUSIONS: E-VAP and L-VAP have different risk factors, highlighting the need for developing specific preventive measures.