Shorter course therapy of serious respiratory infections: new data for new approaches to management

Hospital-based strategies to reduce antibiotic resistance: are they valid in the community setting?

Antimicrobial resistance is an increasing problem worldwide in both the hospital and community settings. Various approaches have been proposed and tested mainly in the hospital environment to reduce this problem; however, few of these have been examined from the perspective of applicability to reversing community-based resistance. It is clear that, in addition to specific antibiotic usage campaigns, a major educational initiative for both prescribers and patients alike is required for the full societal impact of growing antibiotic resistance to be appreciated. This inexorable increase is occurring in the face of a dearth of new antibiotics for community use and even fewer for treating resistant nosocomial gram-negative species. The possible strategies and consequences are discussed.

Early evolution of arterial oxygenation in severe community-acquired pneumonia: a prospective observational study

PURPOSE

Acute respiratory failure requiring mechanical ventilation in severe community-acquired pneumonia has been shown to be a significant negative prognostic factor. We analyzed the early evolution of the Pao(2)/Fio(2) ratio and evaluated its clinical value as an outcome predictor.

MATERIALS AND METHODS

This is a prospective study conducted in a tertiary referral hospital. In 62 adult patients requiring early mechanical ventilation due to severe community-acquired pneumonia, we measured serial changes in Pao(2)/Fio(2) ratio and other clinical variables within the first 48 hours of mechanical ventilation and compared the difference between survivors and nonsurvivors.

RESULTS

The initial Pao(2)/Fio(2) ratio was lower in nonsurvivors (n = 27) than in survivors (n = 35) (158.0 +/- 55.8 vs 117.9 +/- 50.6, P = .025). Over the next 48 hours, the ratio increased significantly in survivors but not in nonsurvivors (analysis of variance, P < .001). An increase in Pao(2)/Fio(2) ratio greater than 56 mm Hg had a sensitivity of 75% and a specificity of 81% of survival. A definite causative pathogen was identified in 36 patients (58%) and the 3 most commonly isolated pathogens were Streptococcus pneumoniae, Staphylococcus aureus, and Klebsiella pneumoniae. Ten patients received inadequate initial empirical antimicrobial therapy, in which the Pao(2)/Fio(2) ratio change was significantly less than those who were adequately treated (analysis of variance, P < .001). Mortality was much higher (86% [6/7]) in patients who received inadequate antibiotics and where Pao(2)/Fio(2) ratio change was less than 56 mm Hg. On multivariate analysis, trend changes in Pao(2)/Fio(2) ratio over 48 hours, shock, and Acute Physiology and Chronic Health Evaluation II score were documented to be independent predictors of mortality.

CONCLUSIONS

A progressive improvement of Pao(2)/Fio(2) ratio during the first 48 hours of mechanical ventilation indicates favorable outcome. Serial measurement of this ratio should be considered in decision making for therapeutic strategy.