III. Ventricle diameter increase during ventricular drainage challenge - A predictor of shunt dependency after subarachnoid hemorrhage.

Hydrocephalus with the need for shunt placement is a common sequela after aneurysmal subarachnoid hemorrhage (aSAH). In 2009 Chan et al. published a formula to predict shunt dependency in SAH patients, the failure risk index (FRI). We reevaluated the FRI within the aSAH population in our hospital and wanted to identify easier measurements forecast shunt dependency. We retrospectively analyzed data from patients with aSAH treated in our neuro-intensive care unit and calculated the FRI according to the paper by Chan et al. 2013 and data were compared to the results of Chan et al. 38 patients were included in this study, 24 female and 14 male. 38% suffered a SAH WFNS I, 19% WFNS II, 24% WFNS III, 5% WFNS IV and 14% WFNS V. 17 patients underwent a shunt implantation (group 1), 21 patients did not (group 2). The calculated FRI Index did not correlate with the expectancy of shunt implantation in 22% of the cases (group 1). In group 2 the FRI index and the prediction of shunt dependency did not match in 33% of the cases. Furthermore, we found the increase of the third ventricle diameter to be predictive in 67% for failed EVD challenge and the decrease of the third ventricle diameter predictive in 67% for successful EVD challenge. In this study, we were not able to confirm the results of the FRI designed by Chan et al within our patient population. Furthermore, we consider the increase of the third ventricle diameter to be a simpler and more reliable predictor of shunt dependency.

Solvent enhancement of reaction selectivity: a unique property of cationic chiral dirhodium carboxamidates.

1,3-Dipolar cycloaddition reactions of nitrones with α,ß-unsaturated aldehydes catalyzed by a cationic chiral dirhodium(II,III) carboxamidate with (R)-menthyl (S)-2-oxopyrrolidine-5-carboxylate ligands in toluene increase reaction rates, give optimum regioselectivities, and enhance stereoselectivities compared to the same reactions performed in traditionally used halocarbon solvents. Rate and enantioselectivity enhancements were also obtained in hetero-Diels-Alder and carbonyl-ene reactions performed in toluene over those obtained in dichloromethane using the diastereomeric chiral cationic dirhodium(II,III) carboxamidate with (S)-menthyl (S)-2-oxopyrrolidine-5-carboxylate ligands. These enhancements are attributed to diminished or absent association of toluene with the catalyst which lessens the relative importance of the uncatalyzed background reaction, and they may also be a consequence of different coordination angles for aldehyde association with rhodium in the different solvent environments. Overall, the enhancement of reaction rates and selectivities with cationic chiral dirhodium(II,III) carboxamidates in toluene suggests broad applications for them in Lewis acid catalyzed reactions.