The impact of spontaneous ventilation on non-operative lung injury in thoracic surgery: a randomized controlled rabbit model study

OBJECTIVES: One-lung ventilation (OLV) with general anaesthesia may increase adverse effects after thoracic surgery, specifically ventilator-induced lung injury. Spontaneous ventilation (SV) has no mechanical ventilation process, thus, we established a rabbit model to assess non-operative lung injury between OLV and SV. METHODS: Thirty-six rabbits were randomly divided into 6 groups: OLV and SV (0, 2 and 4 h). Blood gas analysis was performed after thoracic surgery. Lung tissue and bronchoalveolar lavage fluid were obtained from the non-operative lung. Pathological injury score in lung tissue and tumour necrosis factor alpha (TNF-alpha) level in bronchoalveolar lavage fluid using enzyme-linked immunosorbent assay were determined. Moreover, messenger RNA and protein of TNF-alpha in lung tissue were also determined by quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry. RESULTS: Compared with the OLV group, significantly higher partial pressure of carbon dioxide (47.78 +/- 3.57 vs 38.95 +/- 3.88 mmHg, P < 0.01) and partial pressure of oxygen (101.08 +/- 13.1 vs 85.6 +/- 11.07 mmHg, P < 0.01), as well as a significantly lower pathological injury score (6.83 +/- 1.17 vs 8.83 +/- 1.72, P < 0.05), TNF-alpha level in bronchoalveolar lavage fluid (290.32 +/- 29.38 vs 368.43 +/- 31.26 pg/ml, P < 0.01), TNF-alpha messenger RNA (6.31 +/- 1.13 vs 8.6 +/- 1.34, P < 0.01), immunostaining intensity in lung tissue were found at 4 h in the SV group. However, there are no significant differences between OLV and SV groups at 2 h (P > 0.05), except in TNF-alpha messenger RNA. CONCLUSIONS: Based on this rabbit model, SV for thoracic surgery is not inferior to OLV in terms of lung injury. Considering our results, when performing time-consuming thoracic procedures under OLV, surgeons should more closely examine patients for non-operative lung injury postoperatively.