Perioperative Hyperoxia and Early Pulmonary Epithelial and Glycocalyx-Related Biomarker Trajectories in Laparoscopic Surgery: A Prospective Randomized Study

Although perioperative oxygen therapy is a routine component of general anesthesia, its early biological consequences remain incompletely understood. This prospective randomized study evaluated whether perioperative oxygen concentration influences early biomarker responses in adults undergoing elective laparoscopic lower abdominal surgery. Patients received either normoxia (FiO2 0.35) or hyperoxia (FiO2 0.80) under standardized anesthesia. Clear physiological separation between groups was confirmed by arterial blood gas analysis. The primary biomarker finding was that circulating surfactant protein-A (SP-A) increased significantly in the normoxia group, whereas no comparable increase was observed under hyperoxia. Syndecan-1 and sialic acid showed descriptively similar directional patterns; however, these secondary biomarker findings were interpreted as exploratory and were not robust after Holm correction. By contrast, tumor necrosis factor-alpha (TNF-α) levels were higher postoperatively in the hyperoxia group, while ischemia-modified albumin (IMA) and total protein did not differ significantly between groups. These findings suggest that perioperative hyperoxia was associated with different early circulating biomarker trajectories across pulmonary epithelial and glycocalyx-related domains, without establishing pulmonary or endothelial protection. Further studies are needed to determine whether these early mechanistic findings translate into clinically meaningful outcomes.