Association Between Postoperative Complications and Real-Time Oxidative Stress Measurements Using Electron Spin Resonance: An Observational Study.

Introduction Surgical stress induces oxidative stress, which can affect postoperative recovery. Real-time monitoring of oxidative stress can provide valuable insights for perioperative management. This study aimed to investigate the relationship between perioperative oxidative stress and postoperative complications using real-time ascorbyl free radical (AFR) measurements via electron spin resonance (ESR). Methods Patients who underwent elective surgery were included in this study. Plasma samples were collected before and after surgery. Using the ESR spectrometer installed in the operating room, the intensity of the plasma AFR levels supplemented with dimethyl sulfoxide (AFR/DMSO) was measured. Clinical parameters, including the surgical Apgar score and National Surgical Quality Improvement Program-defined postoperative complications, were obtained from medical records. This study analyzed the relationship between the AFR/DMSO levels, surgical Apgar score, and postoperative complications. The perioperative factors influencing postoperative AFR/DMSO levels were also investigated. Results Postoperative AFR/DMSO levels were significantly lower than the preoperative values (0.26 vs. 0.32, P<0.001). Postoperative AFR/DMSO levels were positively correlated with the surgical Apgar score (r=0.25, P=0.002) and negatively correlated with the number of postoperative complications (r=-0.22, P=0.007). Multivariate analysis identified prolonged surgical duration and elevated postoperative inflammation markers as significant predictors of reduced postoperative AFR/DMSO. Conclusion ESR-based AFR/DMSO is a sensitive real-time indicator of oxidative stress and a valuable biomarker for predicting postoperative outcomes.