[Effects of lung protective ventilation on inhibiting inflammatory mediators released into plasma and bronchial alveolar lavage fluid in acute respiratory distress syndrome caused by pulmonary and extrapulmonary insults in dog]

Abstract

Objective: To observe the changes in oxygenation index and inflammatory mediators in plasma and bronchial alveolar lavage fluid (BALF) of different lung areas (upper lobe, heart lobe, diaphragm lobe) in acute respiratory distress syndrome (ARDS) caused by pulmonary and extra-pulmonary insults with lung protective ventilation treatment in dog.

Methods: Twenty-four male mongrel dogs were randomly divided into ARDSp (ARDS caused by pulmonary disease) experimental group, ARDSp control group, ARDSexp (ARDS caused by extra-pulmonary disease) experimental group, and ARDSexp control group. In ARDSp dogs detergent was introduced intratracheally to cause lung injury, while in ARDSexp dog's oleic acid was given intravenously to produce lung injury. After lung injury, the dogs in the experimental groups received lung protective ventilation treatment (tidal volume: 8 ml/kg, positive end-expiratory pressure (PEEP): 10 cm H2O (1 cm H2O=0.098 kPa)), and the control groups received large tidal volume ventilation (tidal volume: 14-17 ml/kg, PEEP: 0). The contents of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL- 1beta), IL-6 in plasma and BALF from different areas of dog's lung (upper lobe, heart lobe, and diaphragm lobe), and arterial blood gas under lung protective ventilation treatment were measured.

Results: After lung injury, the results of arterial oxygenation index were getting worse, and the contents of TNF-alpha, IL-1beta, and IL-6 in plasma were obviously elevated. The contents of inflammatory mediators in upper lobe and heart lobe of ARDSp dogs were higher than that of ARDSexp dogs (all P<0.05). After receiving lung protective ventilation, the symptoms in the dogs of experimental groups were gradually getting ameliorated compared to control groups, but ARDSexp experimental dogs rallied better than ARDSp experimental dogs.

Conclusion: There are statistical differences in the amount of inflammatory mediators released in BALF from different lung areas and arterial oxygenation amelioration between ARDSp dogs and ARDSexp dogs, and better effects are seen in ARDSexp dogs than ARDSp dogs under lung protective ventilation treatment.