The aim of this prospective observational study is to determine whether sequential quantitative cultures of tracheobronchial secretions (TRBS) in mechanically ventilated (MV) MICU patients (pts) correlate with clinical parameters of lower respiratory infection and influence patient outcome.
The study was conducted in a 7-bed MICU for 1 year period and included all MV pts for >48 hrs. Surgical, trauma,with non pulmonary causes of infection pts and pts presenting with or subsequently developing pneumonia were excluded. Samples of TRBS were obtained during the first 24 hours of intubation (S1) and weekly thereafter for a maximum of 2 weeks (S2, S3) using a simple aspiration catheter and were cultured quantitatively. All had purulent secretions and received empirical antibiotics that were modified according to the culture results.
20 pts, 17M and 3F, mean age 71.95±8.44, mean Apache score at presentation 13.1±6.47 (12 COPD exacerbations) were studied. While 4/20 positive samples were retrieved from S1, positives rose subsequently to 16/20 for S2 to 10/12 for S3. Resistant pseudomonas aeruginosa and acinetobacter species accounted for 4/16 and 8/16 for S2 and 5/10 and 5/10 for S3, respectively. In 13 pts antibiotics were changed according to sensitivities. Mortality was high (15/20), especially in non-COPD pts (8/8), despite the use of appropriate antibiotics and it was not influenced by the type of bacteria cultured. Comparing concentrations >105 cfu to those with <105 cfu there was no positive correlation with fever (>38 C) or leucocytocis (WBC >10500) for the group as a whole, as well as for the subgroups of 12 COPD and 8 non-COPD pts.
Positive cultures of TRBS was a common finding after the first few days in MV MICU pts, with no correlation with fever or leucocytocis. The value of following and treating tracheobronchitis cannot be easily appreciated, since high mortality and persistence of resistant pathogens beyond the first week despite treatment probably reflect the poor health status of these pts. Large scale studies are needed.
N.D. Manolakoglou, None.