Reducing Atelectasis Attenuates Bacterial Growth and Translocation in Experimental Pneumonia

Abstract

Besides being one of the mechanisms responsible for ventilator-induced lung injury, atelectasis also seems to aggravate the course of experimental pneumonia. In this study, we examined the effect of reducing the degree of atelectasis by natural modified surfactant and/or open lung ventilation on bacterial growth and translocation in a piglet model of Group B streptococcal pneumonia. After creating surfactant deficiency by whole lung lavage, intratracheal instillation of bacteria induced severe pneumonia with bacterial translocation into the blood stream, resulting in a mortality rate of almost 80%. Treatment with 300 mg/kg of exogenous surfactant before instillation of streptococci attenuated both bacterial growth and translocation and prevented clinical deterioration. This goal was also achieved by reversing atelectasis in lavaged animals via open lung ventilation. Combining both exogenous surfactant and open lung ventilation prevented bacterial translocation completely, comparable to Group B streptococci instillation into healthy animals. We conclude that exogenous surfactant and open lung ventilation attenuate bacterial growth and translocation in experimental pneumonia and that this attenuation is at least in part mediated by a reduction in atelectasis. These findings suggest that minimizing alveolar collapse by exogenous surfactant and open lung ventilation may reduce the risk of pneumonia and subsequent sepsis in ventilated patients.

Recombinant Human Deoxyribonuclease Shortens Ventilation Time in Young, Mechanically Ventilated Children

“…Atelectasis in our patients may have been caused by mucus hyperviscosity, which is induced multifactorially, 24,25 i.e., by pneumonia-mediated inactivation of surfactant, 26 systemic inflammatory response after cardiopulmonary bypass, 27,28 fluid restriction and diuretics 1 (despite the known beneficial effects, e.g., in acute respiratory distress syndrome 29,30 ), or by young age or mechanical ventilation (trauma) itself. 2 Sudden mucus mobilization episodes were slightly less frequent after dornase alfa treatment than in the group given placebo.…”

The Scientific Basis for Postoperative Respiratory Care

“…The development of atelectasis leads to hypoxemia and translocation of bacteria to the bloodstream, and may be important in creating the heterogeneous lung at risk for ventilator-induced lung injury. [27][28] These physiologic findings led investigators to experiment with methods to increase lung volumes and improve cough postoperatively. These techniques are often referred to in the literature generically as postoperative physiotherapy, which includes coughing and deep breathing, incentive spirometry, percussion and postural drainage, CPAP, positive expiratory pressure (PEP), and other techniques.…”

Open is Better Than Closed

“…However, it increases the atelectasis formation and increasing inspired oxygen further causes a vicious circle with more atelectasis and more need of oxygen. Moreover, atelectasis is a locus of inflammation (8). Thus, an open lung is in my opinion a better lung than a closed lung.…”