Are antioxidant levels measured immediately postoperatively an indicator of magnitude of injury?

Background: Little is known about the changes that occur in antioxidant levels in response to surgical trauma. The antioxidant system may influence recovery and healing after operation. Miller et al described a reliable assay for total antioxidant capacity of serum. We studied changes in antioxidant levels secondary to operation using this assay. Methods: Twenty-seven patients were studied: 14 abdominal and 13 breast cancer operations. Initial blood samples were obtained when starting the preoperative intravenous line, the second in the recovery room, and every 6 hours thereafter. Results: Levels did not correlate with diagnosis, extent of operation, age, body mass index, or complications. Differences between preoperative and postoperative values in the down and up groups were significant at P = 0.002 and P = 0.023, respectively. Differences in initial levels between the down and up groups were significant at P = 0.005. Levels 12 hours after operation were stable. Conclusions: Rapid return to a baseline of approximately 1 μmole/L, regardless of the direction of initial response, supports the concept of a set point for regulation of serum’s antioxidant capacity