Ethics approval and consent to participate
VITdAL-PICU was approved by the Children’s Hospital of Eastern Ontario Research Ethics Board (protocol no. 15/ 18E) on 16-Oct-2015, by the Medical University of Graz Ethics Committee (REB reference 28–619 ex 15/16) on 19-Jan-2017, by the Ethical Scientific Committee of the Concepción Health Service (REB reference 16–03-10) on 24-May-2016, and by the Western University Health Sciences Research Ethics Board (REB number 109099) on 31-Jul-2017. Written informed consent was obtained for each participant by the site investigator or trained delegate prior to any study-related procedures. For participants who were minors (under 16 years of age), informed consent was obtained from a parent and/or legal guardian. Where applicable, assent was also obtained. All methods were carried out in accordance with relevant guidelines and regulations.