Surgical Ligation Level Of The Bronchial Artery Influences Tissue Oxygen Saturation Of The Bronchus And The Incidence Of Postoperative Bronchofistula After Pulmonary Lobectomy

Background: Lobectomy, or the removal of a lobe of the lung, is the most commonly performed lung cancer surgery. One of the most severe postoperative complications is a bronchial stump fistula, which often occurs following a right lower lobectomy. During lymph node dissection, the bronchial arteries, which supply blood to the bronchus, are cut. Subsequently, reduced blood supply to the bronchus may result in bronchofistula. We investigated the relationship between the level of the surgical ligation of the bronchial arteries and the decrease in blood flow at the bronchial stump during a right lower lobectomy. This study aimed to clarify the relationship between the anatomical amputation level of the bronchial artery and the decrease in tissue oxygen saturation at the bronchial stump, allowing us to identify a surgical procedure that reduces the risk of a bronchopleural fistula following pulmonary lobectomy and an appropriate bronchial artery amputation site that could be used in future lobectomies.Methods: We developed a new system (micro-tissue oxygen saturation) that enabled the semi-quantification of the oxygen saturation of thin tissues in pinpoint during video- assisted thoracic surgery. Changes in the blood flow at the bronchial stump were examined during lymph node dissection and bronchial artery amputation using a biological pig lobectomy model.Results: The regional oxygen saturation level at the bronchial wall was 95.5%+/- 1.0% in normal conditions. A gradual decrease in regional oxygen saturation was observed, as the cutting point of the bronchial artery was moved higher. When the bronchial artery coursing into the middle lobe bronchus was preserved, the blood flow in the bronchus was preserved at 82.8%+/- 1.3%. When the branches of the bronchial arteries running both inside and outside of the intermediate bronchial trunk were cut at high positions, regional oxygen saturation level decreased to 55.7%+/- 1.2%.Conclusions: The preservation of at least one bronchial artery at the level of the middle lobe bronchus minimizes the reduction of tissue oxygen saturation at the lower lobe bronchial stump. The ligation of bronchial arteries at a higher position results in desaturation <60%, which may increase the risk of bronchial stump fistula.