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Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Oxidative stress may be involved in occurrence of postoperative delirium (POD) and cognitive dysfunction (POCD). 8-iso-Prostaglandin F2 (8-iso-PGF2), an isoprostane derived from arachidonic acid via lipid peroxidation, is considered a gold standard for measuring oxidative stress. The present study aimed to investigate the ability of postoperative plasma 8-iso-PGF2 levels to predict POD and POCD in elderly patients undergoing hip fracture surgery.', 'Postoperative plasma 8-iso-PGF2 levels of 182 patients were measured by an enzyme-linked immunosorbent assay. We assessed the relationships between plasma 8-iso-PGF2 levels and the risk of POD and POCD using a multivariate analysis.', 'Plasma 8-iso-PGF2 levels and age were identified as the independent predictors for POD and POCD. Based on areas under receiver operating characteristic curve, the predictive values of 8-iso-PGF2 were obviously higher than those of age for POD and POCD. In a combined logistic-regression model, 8-iso-PGF2 significantly enhanced the areas under curve of age for prediction of POD and POCD.
Output:
Are postoperative plasma 8-iso-prostaglandin F2 levels associated with delirium and cognitive dysfunction in elderly patients after hip fracture surgery?