The use of end-tidal argon to detect venous air embolism: foiled by "fake oxygen!".

Venous air-embolism (VAE) potentially catastrophic complication surgery. Based on previous data using changes in end-tidal nitrogen as an indicator of VAE, we surmised that changes in end-tidal argon (EtAr) may be an indicator of VAE. We sought to determine if a commercial mass-spectrometer (PCT Proline Analyzer 61700-8 Class 85, Ametek, Pittsburgh, PA 15238) could be used to detect changes in EtAr in an invitro model.

Ion Association Assisted Lithium Ion "Claw".

N-Methoxycarbonyl-1H-azepine-2,7-dicarboxaldehyde (I) was synthesized via the SeO(2)-mediated oxidation of N-methoxycarbonyl-2,7-dimethyl-1H-azepine. The reductions of I in tetrahydrofuran with (6)Li or (7)Li resulted in anion radicals, which are tightly associated with the lithium cations. EPR and ab initio calculations both show a nonequivalency in all of the protons in I(-*),Li(+) due to the closer approach of the Li(+) to one of the carbonyls and a twist of the ester carbonyl group (slow rotation of the carbamate group) toward the Li(+).