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 α (TNF-α) level in bronchoalveolar lavage fluid using enzyme-linked immunosorbent assay were determined. Moreover, messenger RNA and protein of TNF-α 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-α level in bronchoalveolar lavage fluid (290.32 ± 29.38 vs 368.43 ± 31.26 pg/ml, P < 0.01), TNF-α 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-α 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.