371. Ventilator-Associated Respiratory Infections [VARI]: A New Model for Treatment, Diagnosis and Prevention
Session: Poster Abstract Session: Community and Healthcare Acquired Pneumonia - Epidemiology
Friday, October 21, 2011
Room: Poster Hall B1
Background: Ventilator-associated respiratory tract infections (VARI) include ventilator-associated tracheobronchitis (VAT) and pneumonia (VAP).  Clinical signs of infection and microbiologic cultures of endotracheal aspirates (EA) provide important clues for the diagnosis of VARI.  We studied the natural history of endotracheal colonization and different microbiologic and clinical criteria used to diagnose VARI.

Methods: Daily suctioned EA and clinical data were collected on 188 medical and surgical patients, who were intubated >48 hours.  EA were examined daily by quantitative (Q-EA), semi-quantitative (SQ-EA) culture methods, which were not reported to treating clinicians. Study EA samples were also compared with 51 bronchoalveolar lavage (BAL) samples ordered by treating physicians.  Correlation between different EA microbiologic thresholds used to diagnose VARI were evaluated  by sensitivity, specificity and kappa values.

Results: The incidence of microbiologic VARI was 46% with Q-EA >105 cfu/ml, 31% for Q-EA ≥106 cfu/ml , 44% for SQ-EA having moderate (+++)  growth, and 27% for SQ-EA with heavy (++++)growth.  Incidence rates were lower in all groups when specific clinical criteria for VARI were included.  Excellent correlation was observed between Q-EA >106 cfu/ml and SQ-EA ++++ (sensitivity = 83%,  k = .85); SQ-EA > +++ correlated well with Q-EA >105 cfu/ml (sensitivity 91%, k =  = .86).   Patients with Q-EA ≥106 cfu/ml, compared to  those with lower colonization, had more ICU days (15 vs 12, p<0.01) and study days (7 vs. 4, p<0.001).       

Conclusion: Incidence of VARI varied by specific microbiologic criteria used, and was lower when clinical criteria were added. We found good correlation between Q-EA and SQ-EA culture methods. Heavier EA colonization was associated with poorer patient outcomes.  Serial EA allow earlier diagnosis and therapy of VARI which may prevent VAP and improve patient outcomes.  

Subject Category: C. Clinical studies of bacterial infections and antibacterials including sexually transmitted diseases and mycobacterial infections (surveys, epidemiology, and clinical trials)

Donald Craven, MD, FIDSA1,2, Jana Hudcova, MD3,4, Robin Ruthazer, MPH5, Yuxiu Lei, Ph.D1, Marie Goggin, MT(ASCP)(SM)6, Akmal Sarwar, MD7 and Kenneth Wener, MD8, (1)Center for Infectious Disease & Prevention, Lahey Clinic, Burlington, MA, (2)Tufts University School of Medicine, Burlington, MA, (3)Surgical Critical Care, Lahey Clinic, Burlington, MA, (4)Anaesthesia, Tufts Medical Center, Boston, MA, (5)Tufts Medical Center, Boston, MA, (6)Microbiology, Lahey Clinic, Burlington, MA, (7)Pulmonary & Critical Care Medicine, Lahey Clinic, Burlington, MA, (8)Infectious Disease, Lahey Clinic, Burlington, MA


D. Craven, pfizer: Consultant, Investigator, Scientific Advisor and Speaker's Bureau, Consulting fee, Grant recipient and Speaker honorarium

J. Hudcova, None

R. Ruthazer, None

Y. Lei, None

M. Goggin, None

A. Sarwar, None

K. Wener, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.