1Intensive Care Unit Department, Emergency Medicine Discipline, Hospital das Clínicas, Faculty of Medicine, University of São Paulo, São Paulo, Brazil.2Intensive Care Unit, Hospital Alemão Oswaldo Cruz, São Paulo, Brazil.3Respiratory Intensive Care Unit Department, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.4Research and Education Institute, Hospital Sírio-Libanês, São Paulo, Brazil.5Post-graduation Program in Medical Sciences Department, Faculty of Medicine, University of Ceará, Ceará, Brazil.6Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA.