Recent Advances in Preventing and Managing Postoperative Delirium [version 1; peer review: 2 approved]

Postoperative delirium is a common and harrowing complication in older surgical patients. Those with cognitive impairment or dementia are at especially high risk for developing postoperative delirium; ominously, it is hypothesized that delirium can accelerate cognitive decline and the onset of dementia, or worsen the severity of dementia. Awareness of delirium has grown in recent years as various medical societies have launched initiatives to prevent postoperative delirium and alleviate its impact. Unfortunately, delirium pathophysiology is not well understood and this likely contributes to the current state of low-quality evidence that informs perioperative guidelines. Along these lines, recent prevention trials involving ketamine and dexmedetomidine have demonstrated inconsistent findings. Non-pharmacologic multicomponent initiatives, such as the Hospital Elder Life Program, have consistently reduced delirium incidence and burden across various hospital settings. However, a substantial portion of delirium occurrences are still not prevented, and effective prevention and management strategies are needed to complement such multicomponent non-pharmacologic therapies. In this narrative review, we examine the current understanding of delirium neurobiology and summarize the present state of prevention and management efforts

Delocalized Carbanions. IV. \u3c sup\u3e 1 \u3c/sup\u3e Structural Studies on the Alkali Metal Derivatives of 1- and 2-Methylnaphthalene

Carbon–metal bonding in 1- and 2-naphthylmethyllithium, -sodium, and -potassium was investigated using pmr spectroscopy. In tetrahydrofuran (THF), the chemical shifts of the ring protons of the carbanions relative to naphthalene (δN) increase in the upfield direction in the order Li \u3c Na \u3c K. They were found to follow the equation, where is the cation radius and δN∞ is the extrapolated chemical shift of the corresponding proton in the free anion. The term is interpreted as the amount of C–M bond delocalization in the contact ion pair. Appreciable barriers to rotation about the ring–methylene bonds in the anions show that the partial delocalization is not due to rapid equilibria between ionic and covalent forms. Lack of cation dependence of the spectra of the Li and Na compounds in hexamethlylphosphoramide (HMPA) indicated the presence of solvent separated ion pairs or free ions in this solvent. Comparison of the spectra of the Li compounds in ether and THF led to the conclusion that in ether the Li+ ions may be allylically coordinated to the methylene carbon and a ring carbon. © 1972, American Chemical Society. All rights reserved