Abstract: Objective To explore the value of peripheral blood stress disorder related indexes in the differential diagnosis of acute abdomen.Methods  300 patients with acute abdominal pain admitted from January 2018 to June 2020 (abdominal pain group).Proline peptidase activity, total oxidant status level (TOS), total antioxidant status level (TAS) and oxidative stress index(OSI) in peripheral blood were detected upon admission.According to the treatment outcome, the patients were divided into surgical treatment group (ST group,99 cases), non-surgical treatment group (MT group,102 cases) and non-specific abdominal pain group (NSAP group,99 cases).100 volunteers who underwent physical examination in our hospital were the control group.Univariate and multivariate Logistic regression were used to analyze the independent predictors of surgical treatment.Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of TOS and proline peptidase levels in surgical abdominal pain.Results (1)Peripheral blood TAS level [(36.84±10.08)μmol Trolox equiv./L VS(25.51±7.34)μmol Trolox equiv./L], OSI level [(3.68±1.77) VS (2.48±0.89)] and proline peptidase activity [(1013.58±296.84)U/L vs.(842.65±147.25)U/L] in patients with abdominal pain group were higher than those in control group Group (P>0.05).There was no significant difference in TOS level in peripheral blood between abdominal pain group and control group [(1.10±0.22)μmol H_2O2 equiv./L vs.(1.06±0.24)μmol H_2O2 equiv./L] (P> 0.05).(2) TAS level [(41.06±9.75)μmol Trolox equiv./L vs.(34.81±10.50)μmol Trolox equiv./L vs.(26.95±6.57)μmol Trolox equiv./L] and proline peptidase activity [(1207.58±254.12)U/L vs.(998.65±248.96)U/L vs.(873.65±132.04)U/L] in ST group were significantly higher than those in MT group And NSAP group.The OSI level of ST group was significantly higher than that of NSAP group [(3.90±3.87) vs.(2.42±0.65)], with statistical significance (P>0.05), but there was no statistical significance compared with MT group (3.85±1.08) (P>0.05).(3) Multifactorial Logistic regression analysis showed that plasma TOS level (OR=1.383) and proline peptidase level (OR=1.235) were independent predictors of surgical treatment in patients with emergency abdominal pain.The higher the plasma TOS level and proline peptidase level, the higher the risk of surgical treatment.(4)ROC curve analysis showed that the area under ROC curve (AUC) of plasma TOS for diagnosing surgical abdominal pain was 0.652, and the optimal diagnostic value was 39.65μmol H_2O2 equiv./L.The AUC of proline peptidase was 0.664, and the best diagnostic value was 1696.58U/L.The AUC of combined diagnosis was 0.813, the sensitivity was 78.25%, and the specificity was 59.65%.Conclusion In emergency, plasma proline protease activity and TOS levels have certain reference significance for determining whether patients need urgent surgical treatment.

Key words: acute abdomen, oxidative stress, proline enzyme