Morphological changes in the ventilated lung after thoracic surgery

There are many studies of single lung ventilation (SLV), which are mostly limited to reducing lung damage by changing ventilation strategies or comparing differences in lung damage caused by different lung isolation devices. There is no study comparing the morphological changes of ventilated lungs using different strategies of artificial lung ventilation. The aim of the study was to examine pathomorphological changes in the ventilated lung during thoracic surgery using SLV. A randomized study was performed on 40 patients who underwent thoracic surgery using SLV. After signing the informed consent, the patients were divided into two groups. In the control group (40 patients) with ventilation “by volume” (VCV), in the study group – ventilation “by pressure” (PCV) with the addition of PEEP 5 mm. During surgery in the thoracic cavity with the help of SLV performed transbronchial biopsy of the parenchyma of the ventilated lung to study the pathomorphological changes after ventilation with different modes. The biopsy was performed using a bronchoscope, which was inserted through the endotracheal tube into the lung, opposite the side of the operation (after the end of SLV and “inclusion” of the collapsed lung). The morphological changes caused by the ventilator were investigated. Pathomorphological examination of the non-collapsed lung (which participated in gas exchange during SLV) was as follows: the control group found significant changes in the alveolar wall with its edema, thickening of the interstitial lung, vascular occlusion, severe inflammatory cell infiltration and damage to alveolar structures. The alveoli collapsed and disappeared. The alveolar structures of the study group were better than the control group: pulmonary interstitial and alveolar exudates, as well as inflammatory cell infiltration were significantly reduced compared to those in the control group. The results of the study suggest that the use of PCV with “moderate” PEEP can significantly improve oxygenation and reduce acute ventilatory injury of the lungs compared to VCV during SLV.