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. 2021 Dec 2;48(2):164–178. doi: 10.1007/s00134-021-06587-9

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© Springer-Verlag GmbH Germany, part of Springer Nature 2021

This article is made available via the PMC Open Access Subset for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.

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Fig. 1 — Timeline of important milestones in the general history of clinical trials based on references [2, 3]. A historical timeline of key critical care studies and RCTs is available elsewhere [6]