Materials and Methods
This prospective, physiologic study was conducted in the intensive care unit (ICU) of a tertiary care university hospital between April and June 2021. Approval was obtained by local institutional review board, Comitato Etico Policlinico Gemelli. Written informed consent was obtained by patients’ legal representatives according to committee recommendations (ID UCSC915920/20). Withdrawal of consent to study participation or data analysis by patients or their legal representatives was allowed at any time during the study.