Effects of lung protective ventilation on the inflammatory transmitters in peripheral blood and bronchoalveolar lavage fluid of dogs with acute respiratory distress syndrome caused by pulmonary and extrapulmonary insults

Lixin XIE; Youning LIU; Xiaowei ZHAO; Liangan CHEN; Fengying HAO; Lu CAO

ABSTRACT

BACKGROUND:

Lung protective ventilation strategies and positive endexpiratory pressure (PEEP) have been widely used as an effective ventilation pattern in clinical practice of administration of acute respiratory distress syndrome (ARDS) in recent years, but there arestill great arguments on the therapeutic effects.

OBJECTIVE:

To observe the changes of oxygenation index and inflammatory transmitters in peripheral blood and bronchoalveolar lavage fluid(BALF) of different lung areas [superior area of lung (upper lobe), ventral side of inferior lung (heart lobe), and dorsalis inferior lung (diaphragm lobe)] of ARDS dogs caused by pulmonary and extrapulmonary insults under lung protective ventilation treatment.

DESIGN:

A randomized control animal study.

SETTING:

Department of Respiratory Medicine, the General Hospital of Chinese PLA.MATERIALS Twenty-four adult healthy male mongrel dogs were randomly divided into four groups with 6 dogs in each pulmonary ARDS experimental group, pulmonary ARDS control group, extrapulmonary ARDS experimental group and extrapulmonary ARDS control group.

METHODS:

Models of extrapulmonary ARDS were induced by intravenous injection of oleic acid (0.1-0.15 mg/kg), and the pulmonary ARDS models were established by intratracheal administration of diocty sulfosuccinate sodium salt. After lung injury, the experimental groups received lung protective ventilation treatment (tidal volume 8 mL/kg, PEEP 0.981 kPa)for 3 hours, and the control groups also received ventilation of large tidal volume (tidal volume 14-17 mL/kg, PEEP 0 kPa).MAIN OUTCOME

MEASURES:

① changes of oxygenation index in each group; ② dynamically observed the changes of the inflammatory transmitters [tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL1β) and interleukin-6 (IL-6)] in pe. Ripheral blood and BALF of different lung areas (upper lobe, heart lobe and diaphragm lobe) of ARDS dogs under lung protective ventilation treatment.

RESULTS:

All the 24 dogs were involved in the analysis of results. ①After lung injury, the oxygenation indexes were significantly decreased in all the groups, and the oxygenation indexes after lung protective ventilation in the experimental groups were obviously higher than those in the control groups (P ＜ 0.05). At 2 and 3 hours after lung protective ventilation, the oxygenation indexes in the extrapulmonary ARDS experimental group were markedly higher than those in the pulmonary ARDS experimental group (P＜ 0.05). ② After lung injury, the levels of the inflammatory transmitters in peripheral blood were all obviously increased in all the groups, which were decreased to different extent after the lung protective ventilation treatment,but the therapeutic effect in the pulmonary ARDS experimental group was not as good as that in the extrapulmonary ARDS experimental group. ③The levels of inflammatory transmitters in BALF of lung upper lobe and heart lobe were obviously higher in pulmonary ARDS dogs than in extrapulmonary ARDS dogs.

CONCLUSION:

The ameliorations of the release of inflammatory transmitters and oxygenation index at different areas are obviously different between ARDS dogs caused by pulmonary and extrapulmonary insults, and lung protective ventilation has good effect on extrapulmonary ARDS dogs,but has bad effect on pulmonary ARDS ones.