The Etiological Diagnosis Of Protected Specimen Brush Sampling Lower Respiratory In Pneumonia

Objective:To investigate the clinical application value of fiberoptic bronchoscopy protected specimen brush (FOB-PSB) and blinded protected specimen brush (BPSB) combined with bacteria quantitative culture (QC) in the etiological diagnosis of severe pneumonia.Methods:Sixty five patients in the Respiratory and Critical Care Medicine Intensive Care Unit (RICU) of The First Affiliated Hospital of ZhengZhou University with severe pneumonia via tracheal intubation or tracheostomy with mechanical ventilation were admitted into group from October2010to January2012. Secretions of lower respiratory tract were collected for bacteria quantitative culture via fiberoptic bronchoscopy protected specimen brush (FOB-PSB), blinded protected specimen brush (BPSB) and disposable suction tube. And types of bacteria, pathogen-positive rate and pollution rate of the three separation methods were compared, also the efficacy of using antibiotic therapy based on the drug sensitivity test results was observed.Result: (1)195specimens were collected and one dominant bacteria was selected from each specimen.163pathogens were seperated, with a positive rate83.6%. If staphylococcus epidermidis and bacteria produce melanin as bacteria contamination were excluded, the pathogen-positive rate was70.8%. The results of bacteria quantitative culture showed that Gram-negative bacteria (the pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii as the main pathogenic bacteria) was the main pathogen (119plants,73%); Gram-positive cocci (Staphylococcus aureus as the main pathogenic bacteria) accounted for second.(2)The number of bacteria strains checked out via FOB-PSB-QC, BPSB-QC and ordinary suction method were58(89.2%),54(83.1%) and51(78.5%). There were no obvious statistical significance among the three positive rates (P>0.05). If Staphylococcus epidermidis and melanin-producing bacteria as non-pathogenic bacteria were excluded, the number of pathogens was57strains (87.7%) of FOB-PSB-QC,53strains (81.5%) of BPSB-QC,28(43.1%) of ordinary suction method.(3)According to the results of pathogen positive rate compared with each other: the difference between FOB-PSB-QC and BPSB-QC was no obvious statistical significance (P=0.33), the difference between FOB-PSB-QC and ordinary suction method, BPSB-QC and ordinary suction method were both statistically significant (P<0.01). There were25(15.3%) strains contaminating bacteria with FOB-PSB-QC1strain (1.7%), the BPSB-QC1strain (1.8%), common suction23strain (45%) in163strains positive bacteria. The pollution prevention performance of three methods of compared with each other; there were no significant statistical significance between FOB-PSB-QC and BPSB-QC (P=0.7). The difference between FOB-PSB-QC and ordinary suction method, BPSB-QC and ordinary suction method were both large and statistically significant (P<0.01). Also the distribution of the difference among three groups of detecting pathogens was not statistically significant (P>0.05). If FOB-PSB-QC as the reference standard, the sensitivity of BPSB-QC was82.8%, the value of positive predictive was88.9%.The consistency of bacteria distribution between FOB-PSB-QC and PSB-QC was84.6%, the consistency of bacteria distribution between FOB-PSB-QC and conventional sputum bacterial culture was 48.3%.Conclusion:(1)The sensitivity, specificity and pollution prevention performance of fiberoptic bronchoscopy protected specimen brush sampling (FOB-PSB) combined with bacteria quantitative culture techniques were significantly better than conventional inspection methods. The technology of FOB-PSB combined with bacteria quantitative culture could directly access to the lung foci, and was safe for general use in patients with severe pulmonary infection in RICU.(2)The blinded protected specimen brush (BPSB) had the similar sensitivity and specificity with fiberoptic bronchoscopy protected specimen brush (FOB-PSB) sampling, and it was time-consuming short, low-cost, lower technical requirement. It could be used in clinical practice.(3) Compared with the two above techniques, although ordinary suction technology had drawbacks, due to its less risk, lower cost, lower demands on technology, so it should still be used. But the process should be paid attention to aseptic operation and reducing pollution.