Reducing atelectasis attenuates bacterial growth and translocation in experimental pneumonia.
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.
|Keywords||*Atelectasis/complications/therapy, *Bacterial Translocation, *Disease Models, Animal, Animals, Animals, Newborn, Bacteremia/etiology/mortality, Bronchoalveolar Lavage Fluid/chemistry, Hemodynamic Processes/drug effects, Humans, Infant, Newborn, Irrigation, Pneumonia, Pneumococcal/etiology/mortality/physiopathology/*prevention & control, Positive-Pressure Respiration/*methods, Proportional Hazards Models, Proteins/analysis, Pulmonary Gas Exchange/drug effects, Pulmonary Surfactant-Associated Protein A/analysis, Pulmonary Surfactants/pharmacology/*therapeutic use, Random Allocation, Research Support, Non-U.S. Gov't, Respiratory Distress Syndrome, Newborn/etiology/prevention & control, Respiratory Mechanics/drug effects, Severity of Illness Index, Sodium Chloride, Streptococcus agalactiae/*physiology, Survival Analysis, Swine|
|Persistent URL||dx.doi.org/10.1164/rccm.200312-1779OC, hdl.handle.net/1765/13310|
van Kaam, A.H., Lachmann, R.A., Herting, E., de Jaegere, A., van Iwaarden, F., Noorduyn, L.A., … Lachmann, B.F.. (2004). Reducing atelectasis attenuates bacterial growth and translocation in experimental pneumonia.. American Journal of Respiratory and Critical Care Medicine, 1046–1053. doi:10.1164/rccm.200312-1779OC