TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: Impaired neurodevelopmental outcome represents a major morbidity for survivors of infant heart surgery for congenital heart defects. Previous studies in these neonates have reported preoperative microcephaly, periventricular leukomalacia, and other findings. The hypothesis of this study is that preoperative cerebral blood flow is substantially diminished and might relate to preoperative neurologic conditions.', 'Preoperative brain magnetic resonance imaging was performed. Cerebral blood flow measurements in infants with congenital heart defects were obtained by using a novel noninvasive magnetic resonance imaging technique, pulsed arterial spin-label perfusion magnetic resonance imaging. Cerebral blood flow was measured before the operation under standard ventilation and repeated after increased carbon dioxide.', 'A total of 25 term infants were studied. The average age at the time of the operation was 4.4 +/- 4.6 days. Congenital heart defects varied widely. Microcephaly occurred in 24% (6/25). Baseline cerebral blood flow was 19.7 +/- 9.2 mL . 100 g -1 . min -1 (8.0-42.2 mL . 100 g -1 . min -1 ). Five patients had cerebral blood flow measurements of less than 10 mL . 100 g -1 . min -1 . Mean hypercarbic cerebral blood flow increased to 40.1 +/- 20.3 mL . 100 g -1 . min -1 (11.4-94.0 mL . 100 g -1 . min -1 , P < .001). Pairwise analyses found that low hemoglobin levels were associated with higher baseline cerebral blood flow values ( P = .04). Periventricular leukomalacia occurred in 28% (7/25) and was associated with decreased baseline cerebral blood flow values ( P = .05) and a smaller change in cerebral blood flow with hypercarbia ( P = .003).\Question: Is preoperative cerebral blood flow diminished in neonates with severe congenital heart defects?

SOLUTION: Structural brain abnormalities are common in these neonates before surgical intervention. Preoperative cerebral blood flow for this cohort was low and drastically reduced in some patients. Low cerebral blood flow values were associated with periventricular leukomalacia. Carbon dioxide reactivity was preserved but might be compromised by some aspects of the cardiac anatomy. The full spectrum of cerebral blood flow measurements with this technique in congenital heart defects and their long-term significance require continued investigation.

PROBLEM: Context: One anesthesiologist performance metric is the incidence of "prolonged" (15 min or longer after dressing complete) times to extubation. The authors used several methods to identify the performance outliers and assess whether targeting these outliers for reduction could improve operating room workflow.', "Time to extubation data were retrieved for 27,757 anesthetics and 81 faculty anesthesiologists. Provider-specific incidences of prolonged extubation were assessed by using unadjusted frequentist statistics and a Bayesian model adjusted for prone positioning, American Society of Anesthesiologist's base units, and case duration.", '20.31% of extubations were "prolonged," and 40% of anesthesiologists were identified as outliers using a frequentist approach, that is, incidence greater than upper 95% CI (20.71%). With an adjusted Bayesian model, only one anesthesiologist was deemed an outlier. If an average anesthesiologist performed all extubations, the incidence of prolonged extubations would change negligibly (to 20.67%). If the anesthesiologist with the highest incidence of prolonged extubations was replaced with an average anesthesiologist, the change was also negligible (20.01%). Variability among anesthesiologists in the incidence of prolonged extubations was significantly less than among other providers.\Question: Is prolonged Operative Time to Extubation a Useful Metric for Comparing the Performance of Individual Anesthesia Providers?

SOLUTION: Bayesian methodology with covariate adjustment is better suited to performance monitoring than an unadjusted, nonhierarchical frequentist approach because it is less likely to identify individuals spuriously as outliers. Targeting outliers in an effort to alter operating room activities is unlikely to have an operational impact (although monitoring may serve other purposes). If change is deemed necessary, it must be made by improving the average behavior of everyone and by focusing on anesthesia providers rather than on faculty.

PROBLEM: Context: Systemic activation of hemostasis and fibrolysis has been shown to be related to tumor progression in patients with malignancies such as lung cancer and colorectal cancer, but there has been no report of these clotting abnormalities in esophageal cancer. We investigated the clinical importance of measuring plasma levels of D-dimer (DD), which is a marker of the hypercoagulable stage, in preoperative patients with esophageal cancer.', 'Preoperative plasma DD levels were measured in 96 patients with primary esophageal cancer who were scheduled for esophagectomy with lymphadenectomy without preoperative treatment at our hospital. Results were correlated with the clinicopathological findings.', 'Significantly different plasma DD levels were found with respect to histologic T (p = 0.0015), histologic N (p < 0.0001), number of metastatic nodes (p < 0.0001), and histologic stages (p < 0.0001). The number of lymph node metastases (0/1 to 3/4 to 7/8-) was found to have the strongest association with DD level among the significant clinicopathologic factors (Spearman rank correlation 0.591, p < 0.0001). The most useful cut-off level of the plasma DD levels for diagnosis of lymph node metastasis was determined to be 0.4 microg/mL, with specificity and sensitivity for lymph node metastasis being 62.9% and 88.2%, respectively.\Question: Do plasma D-dimer levels show correlation with number of lymph node metastases in patients with esophageal cancer?

SOLUTION:
Plasma DD levels are useful for assessing lymph node metastasis in patients with esophageal cancer and should be measured preoperatively.