Effects of Different Concentrations of Inhaled Oxygen on Lung Collapse and Oxidative Stress in Patients With One Lung Ventilation, a Single-Center Prospective, Double-Blinded, Randomized Controlled Trial.

Background: During thoracoscopic surgery, the anestheologist assure an adequate oxygen supply to the body, but at the same time, to improve the surgical field by completely collapsing the lung on the surgical side. However, incomplete lung collapse remains problematic. Increasing the inhaled oxygen concentration might accelerate gas dispersion from the alveoli, but continuous high oxygen may aggravate oxidative stress. The selection of inhaled oxygen concentration during OLV is still controversial. This study intends to explore this issue from the perspective of collapse effect and the degree of oxidative stress. Methods: This study included patients aged 18-65 undergoing thoracoscopic lobectomy, divided into two groups: one receiving 70% oxygen (70% group) and the other 100% oxygen (100% group) during surgery. Lung collapse was evaluated upon camera entry into the chest cavity, and blood samples were collected preoperatively, 30 min after OLV, and on the second postoperative day. Results: Both groups were similar in baseline characteristics. The 100% oxygen group showed significantly greater declines in lung volume and elasticity scores at 5 and 10 min post-thoracic entry compared to the 70% group ( Conclusion: High/pure inhaled oxygen may improve the lung collapse speed and provide a better field of vision for thoracic surgery. Although pure oxygen ventilation aggravated short-term oxidative stress, the effect was insignificant on the second postoperative day.