Pre-operatieve hemodynamische optimalisatie door middel van het verhogen van het zuurstof-aanbod bij hoog-risico-chirurgie

Preoperative hemodynamic optimization by means of augmenting oxygen delivery is an attractive concept to reduce morbidity after major surgery. Several prospective controlled randomised studies demonstrate a positive effect on mortality and morbidity. However, it is still uncertain which patients will benefit most from such a policy and by what means preoperative optimization is best achieved. We believe that the target of optimization should not be a prefixed value for oxygen delivery, but rather one individualized for each patient ("tune-up"). In this regard, a better preoperative fluid-status appears to be most essential

Heliolitid corals and their competitors: a case study from the Wellin patch reefs, Middle Devonian, Belgium

peer reviewedWellin patch reefs are small Upper Eifelian build?ups within the fine?grained argillaceous limestone of the Hanonet Formation. Whereas the reefs themselves are not well exposed, their fossil assemblage is accessible in the hills near the town of Wellin, approximately 40xA0km SE of Dinant in Belgium. It is especially rich in massive stromatoporoids, heliolitids and other tabulate corals. They exhibit predominantly domical and bulbous morphologies. This paper focuses primarily on the palaeoautoecology of the heliolitid corals and their relationships with other organisms. Cases of mutual overgrowth between heliolitids, other corals and stromatoporids suggest a high degree of competition for space on the reefs, possibly related to the scarcity of hard substrates. Coral and stromatoporoid growth forms, as well as the prevalence of micritic matrix, point to a relatively low energy environment. However, abundant growth interruption surfaces, sediment intercalations and rejuvenations of corals suggest episodically increased hydrodynamic regime and sediment supply. It is inferred that the patch reefs developed in a relatively shallow environment, where the reefal assemblage was regularly affected by storms. Heliolitids exhibited high sediment tolerance and relied on passive sediment removal for survival. They also could regenerate effectively and commonly overgrew their epibionts, after the colony’s growth was hampered by the sediment. This is recorded in extremely abundant growth interruption surfaces, which allow the analysis of the impact of sediment influxes on the heliolitid corals. ? 2021 Lethaia Foundation. Published by John Wiley & Sons Lt