Given a passage with a context and an answer, 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.
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Question: Context: The aim of the present study was to evaluate baseline regional cerebral oxygen saturation (rSO2) values and identify factors influencing preoperative rSO2 in elective minor surgery.', 'Observational analysis post-hoc.', 'Observational post-hoc analysis of data for the patient sample (n=50) of a previously conducted clinical trial in patients undergoing tumourectomy for breast cancer or inguinal hernia repair. Exclusion criteria included pre-existing cerebrovascular diseases, anaemia, baseline pulse oximetry <97% and low quality rSO2 sensor signals. Demographic data, comorbidities, and ASA physical status as well as height and weight were collected prospectively from all patients. Baseline rSO2 values were recorded while the patient breathed room air, using the INVOS 5100C monitor™️ (Covidien, Dublin, Ireland).', 'Thirty-seven women (72%) and 13 men (28%) 48 13 years of age were enrolled in this study. Baseline rSO2 was 62.01 10.38%. Baseline rSO2 was significantly different between men (67.6 11.2%) and women (60 9.4%), (P=0.023). There were also differences between baseline rSO2 and ASA physical status (ASA I: 67.6 10.7%, ASA II: 61.6 8.4%, ASA III: 55.8 13.9%, P=0.045). Baseline rSO2 had a positive correlation with body weight (r=0.347, P=0.014) and height (r=0.345, P=0.014). We also found significant differences in baseline rSO2 among patients with and without chronic renal failure (P=0.005). No differences were found in any other studied variables.
Answer: Non-modifiable patient characteristics (ASA physical status, sex, chronic renal failure, body weight and height) influence baseline rSO2.

Answer: Do baseline cerebral oximetry values depend on non-modifiable patient characteristics?

Question: Context: Women have poorer outcomes after vascular surgery as compared to men as shown by studies recently. Frailty is also an independent risk factor for postoperative morbidity and mortality. This study examines the interplay of gender and frailty on outcomes after infrainguinal vascular procedures.', 'The American College of Surgeons National Surgical Quality Improvement Program database was used to identify all patients who underwent infrainguinal vascular procedures from 2005-2012. Frailty was measured using a modified frailty index (mFI; derived from the Canadian Study of Health and Aging). Univariate and multivariate analysis were performed to investigate the association of preoperative frailty and gender, on postoperative outcomes.', 'Of 24,645 patients (92% open, 8% endovascular), there were 533 deaths (2.2%) and 6198 (25.1%) major complications within 30 d postoperatively. Women were more frail (mean mFI = 0.269) than men (mean mFI = 0.259; P < 0.001). Women and frail patients (mFI>0.25) were more likely to have a major morbidity (P < 0.001) or mortality (P < 0.001) with the highest risk in frail women. On multivariate logistic regression analysis, female gender and increasing mFI were independently significantly associated with mortality (P < 0.05) as well as major complications. The interaction of gender and frailty in multivariate analysis showed the highest adjusted 30-d mortality and morbidity in frail females at 2.8% and 30.1%, respectively and that was significantly higher (P < 0.001) than nonfrail males, nonfrail females and frail males.
Answer: Female gender and frailty are both associated with increased risk of complications and death following infrainguinal vascular procedures with the highest risk in frail females. Further studies are needed to explore the mechanisms of interaction of gender and frailty and its effect on long-term outcomes for peripheral vascular disease.

Answer: Do gender and frailty predict poor outcomes in infrainguinal vascular surgery?

Question: Context: Treatment with oxaloacetate after traumatic brain injury has been shown to decrease blood glutamate levels and protect against the neurotoxic effects of glutamate on the brain. A number of potential mechanisms have been suggested to explain oxaloacetate-induced neuroprotection. We hypothesize that the primary mechanism by which intravenous oxaloacetate provides neuroprotection is by activation of the blood glutamate-scavenging enzyme glutamate-oxaloacetate transaminase, increasing thereby the driving force for the efflux of excess glutamate from brain interstitial fluids into blood. If so, coadministration of maleate, a glutamate-oxaloacetate transaminase-blocker is expected to prevent the neuroprotective effects of oxaloacetate.', 'A neurological severity score (NSS) was measured 1 hour after closed head injury (CHI) in rats. Then, rats received 30 microL/min/100 g infusion of saline, or 1 mmol/100 g solution of oxaloacetate, maleate, or a mixture of oxaloacetate and maleate. NSS was reassessed at 24 and 48 hour after CHI. Blood glutamate and glucose levels were measured at 0, 60, 90, and 120 minutes.', 'NSS improved significantly at 24 hour (P<0.001) and 48 hour (P<0.001) only in the rats treated with oxaloacetate. Blood glutamate decreased significantly in the oxaloacetate-treated group at 90 minute (at the conclusion of oxaloacetate administration) (P<0.00001), but not in the control, maleate or oxaloacetate+maleate groups. A strong correlation r2=0.86 was found to exist between the percent decrease in blood glutamate levels and percent improvement in NSS.
Answer: The results of this study demonstrate that the primary mechanism by which oxaloacetate provides neuroprotective activity after CHI is related to its blood glutamate scavenging activity. Management of blood glutamate concentration may have important implications in the treatment of acute brain conditions, including CHI and stroke.

Answer:
Is the neuroprotective effects of oxaloacetate in closed head injury in rats mediated by its blood glutamate scavenging activity : evidence from the use of maleate?