Relationship Between Bacterial Infection And Blood Gas Analysis In Patients With Acute Exacerbations Of Chronic Obstructive Pulmonary Disease

Objective:Bacterial infections are the main reasons of acute exacer-bations of chronic obstructive pulmonary disease (AECOPD) with acute exacerbation and are also involved in the pathogenesis of COPD. This study is to investigate the distributive charateristics of strains isolated from patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and the relation between bacterial infection and arterial partial pressure of oxygen(PaO2) and carbon dioxide(PaCO2) in patients with AECOPD.Methods:From Dec 2008 to Mar 2010, there were 214 inpatients with AECOPD diagnosed according to GOLD 2006 standard in Department of Pulmonary Medicine, the First Hospital of Dalian Medical University. A total of 184 qualified sputum specimens were collected from these patients, in which conventional culture and identification of bacteria was conducted. PaO2 and PaCO2 level of these patients were simultaneously tested in the admission. Determine whether applying mechanical ventilation according to the clinical manifestations and results of blood gas analysis.Results:A total of 56 trains of bacteria were isolated. The positive rate of Sputum culture was 30.4%. Most of pathogens isolated were gram-negative bacilli (64.3%), including Klebsielia pneumoniae (17.9%,10 strains) and Acinetobacter baumannii (14.3%,8 strains). The nonfer-menter of high antimicrobial resistance in clinic occupied 32.1%(18 strains). Gram-positive cocci occupied 10.7%, with 7.1%(4 strains)of Staphylo-coccus aureus being the highest. Fungi occupied 25.0%,with 19.6%(11 strains) of Candida albicans being the highest. The PaO2 of positive group in sputum culture was significantly lower than that of negative group (63.36±25.08mmHg vs.73.85±18.23mmHg,P=0.006). The PaCO2 of positive group in sputum culture was significantly higher than that of negative group (59.57±19.18mmHg vs.47.95±14.40mmHg, P=0.000). The ratio of mechanical ventilation in positive group was significantly higher than that of negative group (16/56 vs.8/128, P=0.000).Conclusions:Pathogens of inpatients with AECOPD are mainly gram-negative bacilli in our area. The rate of nonfermentative infection was higher. The rate of gram-positive bacterial infection was lower. There are some differences in bacterial spectrum between our and other areas. Take full account of geographical distribution and epidemiological characteri-stics of pathogenic bacteria in the initial choice of antibiotics. Detection of bacterial spectrum shoud contribute to the local empirical anti-infective therapy. Critical patients indicated by blood gas analysis, who are often complicated by bacterial infection, should be given comprehensive treatment measures on the basis of reasonable antibiotic treatment to avoid delaying treatment-time.