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: Monitoring renal function is crucial in children undergoing chemotherapy. To date, a combination of routine serum creatinine (SCR) monitoring with occasional determination of creatinine clearance ratio (CCR) is widely used as clinical standard for this purpose. Both methods have their limitations regarding diagnostic value (SCR) or practicability (CCR), especially in young children. Diagnostic alternatives, such as glomerular filtration rate (GFR) estimation formulas have not been proved to be superior. The aim of the study was to evaluate whether serum cystatin C (CysC) may have a diagnostic impact on pediatric patients.', 'CysC, SCR, several GFR estimation formulas (Counahan-Barratt, Ghazali-Barratt, Schwartz, Shull, Traub), and CCR were studied in 80 pediatric cancer patients (age range: 0.17-17.9 years) during their chemotherapy. Special attention was given to children under the age of 3 in whom accurate urine collection for CCR is difficult.', 'All parameters correlated similarly well with CCR. Total accuracy was 66% and 67% for CysC and SCR, respectively. In very young children (<3 years), correlation with CCR was for CysC r = -0.74 with an area under the curve (AUC) of 0.646, and for SCR r = -0.27 with AUC = 0.594. Total accuracy was 60% for CysC, 50% for SCR.\Question: Is serum cystatin C a suitable marker for routine monitoring of renal function in pediatric cancer patients , especially of very young age?

SOLUTION: CysC represents a suitable marker for monitoring renal function in pediatric cancer patients. In young children (<3 years), CysC may have a better diagnostic value than SCR. Future studies should show if CysC can improve renal monitoring by replacing SCR, especially in very young children.

PROBLEM: Context: To investigate the impact of prophylactic hyperoxic ventilation with Fio2 0.6 on the physiologic limit of acute normovolemic anemia.', 'Prospective, controlled, randomized experimental study.', 'Experimental animal laboratory of a university hospital.', 'Fourteen anesthetized domestic pigs.', 'Animals were randomly ventilated with either Fio2 0.21 (group 0.21, n = 7) or Fio2 0.6 (group 0.6, n = 7), and acute anemia was induced by isovolemic blood-for-hydroxy-ethylstarch (HES) exchange using a 6% HES solution (130/0.4).', 'The blood-for-HES-exchange was continued until a sudden decrease of total body oxygen consumption indicated the onset of oxygen supply dependency (primary end point); the corresponding hemoglobin (Hb) concentration was defined as "critical" (Hb(crit)). Secondary end points were changes in myocardial function, central hemodynamics, oxygen transport, and tissue oxygenation. Compared with room air ventilation (Fio2 0.21), hyperoxic ventilation with Fio2 0.6 enabled a larger blood-for-HES-exchange (139%, 124/156) of circulating blood volume vs. 87% (68/94, p < .05), until Hb(crit) was reached (1.5 g/dL [1.4/2.1] vs. 2.4 g/dL [2.0/2.8], p < .05). At Hb 2.4 g/dL (i.e., Hb(crit) in group 0.21), animals of group 0.6 still presented with superior oxygen transport, tissue oxygenation, and hemodynamic stability. However, hemodynamic and oxygen transport variables were found deteriorated more severely at Hb 1.5 g/dL (i.e., Hb(crit) of group 0.6) compared with group 0.21 at Hb 2.4 g/dL.\Question: Does hyperoxic ventilation increase the tolerance of acute normovolemic anemia in anesthetized pigs?

SOLUTION: During cell-free volume replacement, hyperoxic ventilation with Fio2 0.6 generates a readily usable plasmatic oxygen reserve and thereby increases the tolerance toward acute normovolemic anemia.

PROBLEM: Context: Volatile anesthetics exert cardioprotective effects during myocardial ischemia. This investigation examined the regional systolic and diastolic mechanical responses to brief left anterior descending coronary artery (LAD) occlusion in the central ischemic zone and in remote normal myocardium in the conscious state and during desflurane and isoflurane anesthesia.', 'Eighteen experiments were performed in nine dogs chronically instrumented for measurement of aortic and left ventricular pressure, cardiac output, LAD coronary blood flow velocity, and LAD and left circumflex coronary artery subendocardial segment length. Regional myocardial contractility was evaluated with the slope of the preload recruitable stroke work relationship determined from a series of left ventricular pressure-segment length diagrams in the LAD and left circumflex coronary artery zones. Diastolic function was assessed with a time constant of isovolumic relaxation (tau), maximum segment lengthening velocity in LAD and left circumflex coronary artery regions, and regional chamber stiffness constants derived using monoexponential and three-element exponential curve fitting in each zone. On separate experimental days, hemodynamics and indices of regional functional were obtained in the conscious state and during 1.1 and 1.6 minimum alveolar concentration end-tidal desflurane or isoflurane before and during LAD occlusion.', 'In conscious dogs, LAD occlusion abolished regional stroke work, increased chamber stiffness (monoexponential: 0.39 +/- 0.04 during control to 1.34 +/- 0.39 mm-1 during LAD occlusion), and decreased the rate of early ventricular filling in the ischemic zone. These changes were accompanied by increased contractility (slope: 103 +/- 8 during control to 112 +/- 7 mmHg during LAD occlusion), rapid filling rate (maximum segment lengthening velocity: 46 +/- 5 during control to 55 +/- 7 mm.s-1 during LAD occlusion), and chamber stiffness (monoexponential: 0.43 +/- 0.05 during control to 1.14 +/- 0.25 mm-1 during LAD occlusion) in the normal region. Increases in tau were also observed in the conscious state during the period of myocardial ischemia. Desflurane and isoflurane increased tau and decreased the slope and maximum segment lengthening velocity in a dose-related manner. Monoexponential and three-element element exponential curve fitting were unchanged by the volatile anesthetics in the absence of ischemia. Myocardial contractility and rapid filling rate were enhanced in the nonischemic region during LAD occlusion in the presence of desflurane and isoflurane. In contrast to the findings in the conscious state, ischemia-induced increases in tau and chamber stiffness in the ischemic and normal zones were attenuated during anesthesia induced by desflurane and isoflurane.\Question: Do desflurane and isoflurane exert modest beneficial actions on left ventricular diastolic function during myocardial ischemia in dogs?

SOLUTION:
The results indicate that increases in contractility of remote myocardium during brief regional ischemia were preserved in the presence of desflurane and isoflurane anesthesia. In addition, desflurane and isoflurane blunted ischemia-induced increases in tau and regional chamber stiffness in both the ischemic and nonischemic zones. These results demonstrate that the volatile anesthetics may exert important beneficial actions on left ventricular mechanics in the presence of severe abnormalities in systolic and diastolic function during ischemia.