Effect of lung protective ventilation strategy on oxygenation and pulmonary inflammatory response in dogs with severe smoke inhalation injury / 中国中西医结合急救杂志

ABSTRACT

Objective To observe the effect of lung protective ventilation strategy on oxygenation and pulmonary inflammatory response in dogs with severe smoke inhalation injury.Methods Twelve local healthy male dogs were selected and anesthetized underwent endotracheal intubation, the time controlled smoke was applied to replicate the model of severe smoke inhalation injury, and they were divided into two groups according to the random number table conventional ventilation group (CV group) and protective ventilation group (PV group), each receiving corresponding ventilation mode for 8 hours respectively. The blood gas analyses were detected before injury, immediately after injury and at ventilation for 2, 4, 6, 8 hours. The contents of tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10) in serum were detected by the enzyme-linked immunosorbent assay (ELISA) at each time point. Animals were killed after 8-hour ventilation, and different parts of the lung tissues were obtained for pathological examinations of lung tissues and evaluation of injury scores. The levels of inflammatory factors as TNF-α and IL-10 in lung homogenates were measured by ELISA.Results The arterial partial pressure (PaO2) levels in CV and PV groups were significantly decreased after injury compared with those before injury [mmHg (1 mmHg = 0.133 kPa) 57±19 vs. 128±31, 58±15 vs. 126±22, bothP 0.05). At 6 hours ventilation, PaO2 level in PV group was significantly higher than that in CV group (mmHg 121±11 vs. 105±11,P 0.05). The histopathological changes revealed that there were alveolar tissue edema and inflammatory cells infiltration in both groups, the degree of severity in CV group was more prominent and its pulmonary tissue injury score was higher than that in PV group (3.68±0.22 vs. 3.27±0.35, P < 0.05). The serum levels of TNF-α and IL-10 after smoke injury were significantly increased in CV and PV groups [TNF-α (μg/L) 4.32±1.13 vs. 0.35±0.11, 4.51±2.02 vs. 0.41±0.08; IL-10 (ng/L) 16.73±2.31 vs. 4.27±0.56, 18.39±3.15 vs. 4.03±1.07, allP < 0.01]. Compared with CV group, the levels of TNF-α were significantly lower at 6 hours and 8 hours of ventilation [6 hours (μg/L) 2.62±0.34 vs. 3.65±1.08, 8 hours (μg/L) 3.02±0.31 vs. 4.21±1.27, bothP < 0.05), while the contents of IL-10 were obviously increased in PV group [6 hours (ng/L) 21.07±2.95 vs. 16.11±3.02, 8 hours (ng/L) 23.57±2.69 vs. 18.28±3.21, bothP < 0.05]. The content of TNF-α in lung homogenate in CV group was significantly higher than that in PV group (μg/L 5.85±2.57 vs. 3.08±1.17,P < 0.05), but the content of IL-10 in lung homogenate of CV group was markedly lower than that in CP group (ng/L 19.64±3.16 vs. 24.05±2.09, P < 0.05).Conclusion Lung protective ventilation strategy can effectively improve oxygenation and pulmonary inflammatory response in dogs with severe smoke inhalation injury, thus the lung injury is alleviated and the strategy has protective effect on damaged lung tissues.