Improving Outcome in Gastrointestinal and Hepatopancreaticobiliary Surgical Oncology by Preoperative Risk Assessment and Optimization of Perioperative Care

This chapter discusses the most important challenges in the perioperative phase of the oncology patient undergoing surgery of the gastrointestinal tract. Because of the aging population, the surgeon is ever more confronted with frail patients at risk for an adverse surgical outcome. The chapter therefore reviews factors contributing to an impaired postoperative outcome such as sarcopenia, frailty, cachexia, and malnutrition and gives an insight into their pathophysiology. Next, it provides an overview of validated preoperative classification systems to identify the patients at risk for surgical complications. Furthermore, it discusses the most essential recommendations of standardized care for patients undergoing hepatopancreaticobiliary, gastric, and colorectal surgery. Special attention is paid to the use of clinical pathways in the perioperative phase that are aimed at a multimodal approach of reducing surgical morbidity by lowering the perioperative physiological and psychological stress. Recent literature is discussed regarding care in the intensive care unit, and the final paragraph focuses on improving postoperative outcome by means of prehabilitation or exercise as well as dietary interventions and optimized nutrition

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements