title: The impact of onset time on the isolated pathogens and outcomes in ventilator associated pneumonia.
abstract: Several guidelines base the empirical therapy of ventilator-associated pneumonia (VAP) on the time of onset. However, there is emerging evidence that the isolated microorganisms may be similar regardless of onset time. This study evaluated the characteristics and outcomes of VAP with different onset times. All of the mechanically ventilated patients admitted to the ICU of a 900-bed tertiary-care hospital between 01/08/2003 and 31/12/2010 were prospectively followed for VAP development according to the National Healthcare Safety Network criteria. The patients were categorized into four groups: EO if VAP occurred within 4 days of intubation and hospital admission; LO if VAP occurred after 4 days of admission; EL if VAP occurred within 4 days of intubation, but after the fourth hospitalization day; and LL if VAP occurred after the fourth day of intubation and hospitalization. Out of the 394 VAP episodes, 63 (16%) were EO episodes, 331 (84.0%) were LO episodes, 40 (10.1%) were EL episodes and 291 (73.1%) were LL episodes. The isolated microorganisms were comparable among the four groups, with a similar rate of potentially multidrug resistant organisms in the EO-VAP (31.7%), LO-VAP (40.8%), EL-VAP (37.5%) and LL-VAP (43.3%) samples. The hospital mortality was 24% for EO-VAP cases, 28% for LO-VAP cases, 40% for EL-VAP cases and 49% for LL-VAP cases. However, in the adjusted multivariate analysis, neither LO-VAP, EL-VAP nor LL-VAP was associated with an increased risk of hospital mortality compared with EO-VAP (OR, 0.86 95% CI, 0.34-2.19; 1.22; 95% CI, 0.41-3.68, and 0.95; 95% CI, 0.43-2.10, respectively). In this study, the occurrence of potential multidrug resistant pathogens and the mortality risk were similar regardless of VAP timing from hospital admission and intubation. The bacterial isolates obtained from the VAP cases did not follow an early vs. late-onset pattern, and thus, these terms may not be clinically helpful.
authors.affiliation: Intensive Care Department, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City Riyadh, Saudi Arabia. Electronic address: raymondkhan@yahoo.com.
authors.forename: Raymond
authors.initials: R
authors.lastname: Khan
authors.affiliation: Intensive Care Department, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City Riyadh, Saudi Arabia. Electronic address: aldorzih@yahoo.com.
authors.forename: Hasan M
authors.initials: HM
authors.lastname: Al-Dorzi
authors.affiliation: College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City Riyadh, Saudi Arabia. Electronic address: hani_t@hotmial.com.
authors.forename: Hani M
authors.initials: HM
authors.lastname: Tamim
authors.affiliation: Intensive Care Department, King Abdulaziz Medical City Riyadh, Saudi Arabia. Electronic address: rishu421@yahoo.com.
authors.forename: Asgar H
authors.initials: AH
authors.lastname: Rishu
authors.affiliation: Infection Prevention & Control Program, King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences Riyadh, Saudi Arabia. Electronic address: balkhyh@ngha.med.sa.
authors.forename: Hanan
authors.initials: H
authors.lastname: Balkhy
authors.affiliation: Infection Prevention & Control Department, College of Public Health and Health Informatics, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City Riyadh, Saudi Arabia. Electronic address: ramadana@ngha.med.sa.
authors.forename: Aiman
authors.initials: A
authors.lastname: El-Saed
authors.affiliation: Intensive Care Department, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City PO Box 22490, Riyadh 11426, Saudi Arabia. Electronic address: yaseenarabi@yahoo.com.
authors.forename: Yaseen M
authors.initials: YM
authors.lastname: Arabi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000453:epidemiology* / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D053717:Pneumonia, Ventilator-Associated / Q000453:epidemiology* / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D011446:Prospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D062606:Tertiary Care Centers; D013997:Time Factors; D016896:Treatment Outcome
keywords: Critically ill; Early onset; Late-onset; Microbiology; Outcomes; Ventilator-associated pneumonia