2003 OPEN FORUM Abstracts
PREDICTIVE VALUE OF THE GRAM STAIN IN THE DIAGNOSIS OF VENTILATOR ASSOCIATED PNEUMONIA (VAP) FROM BRONCHOSCOPIC AND BLIND BRONCHOALVEOLAR LAVAGE (BAL) SPECIMENS.
Robert S Campbell RRT FAARC, Mark Shapiro MD, Richard D Branson RRT FAARC, Joseph Cuschieri MD, Bradley R Davis MD, Kenneth Davis Jr. MD, Amy McDonald MD, Sandra L Miller MD, Jay A Johannigman MD, Joseph S Solomkin MD. University of Cincinnati College of Medicine, Cincinnati, OH 45267.
INTRODUCTION: Diagnosis of VAP is challenging and is aided by quantitative, microbiological assessment of BAL fluid. Early identification of infecting organisms may lead to more timely and appropriate antibiotic (AB) coverage, which may reduce mortality and morbidity associated with VAP. Ruling out VAP may reduce the cost and morbidity associated with inappropriate AB use. We reviewed the correlation between the gram stain (GS) and final culture (CX) result from BAL specimens obtained blindly (BAL-blind) or by bronchoscopy (BAL-bronch) in pts meeting clinical criteria for VAP between 1-1-03 and 6-30-03.
Methods: All SICU patients admitted for > 72 hours were eligible for the study. BAL-bronch was done using 3-5 aliquots of 25 ml (both lungs sampled), with the first aliquot being discarded. BAL-blind was performed by respiratory care practitioners with a 13-french, plugged-telescoping catheter (CombiCath, ProdiMed) using a single 40 ml aliquot and manual aspiration of the specimen. The GS of each specimen was compared to the CX result for correlation and calculation of the sensitivity (sens), specificity (spec), positive predictive value (PPV), and negative predictive value (NPV). Correlation was done on all specimens by technique and a separate correlation was assessed for the first specimen for each pt.
RESULTS: 425 pts were admitted to the SICU during the study period, of which 148 were eligible for the study (based on the LOS requirement). There were 37 BAL-bronch specimens sent from 31 pts and 93 BAL-blind specimens sent from 51 pts. 21 pts were sampled using both techniques and 87 pts were never sampled at all. Sens, spec, PPV, and NPV for BAL-bronch was 81, 53, 65, and 71% for all specimens and 78, 54, 70, and 64% for the first specimen only. Sens, spec, PPV, and NPV for BAL-blind was 81, 73, 78, and 77% for all specimens and 84, 81, 81, and 84% for the first specimen only. 3 (8%) BAL-bronch and 1 (1%) BAL-blind specimens were contaminated. Overall time to first BAL was 7 days, 6 days for BAL-blind and 8 days for BAL-bronch.
CONCLUSION: Determination of initial AB coverage using the GS from BAL appears warranted. Correlation of GS to CX is better with BAL-blind. AB use may be avoided in up to 34% of pts with suspected VAP.