Acknowledgements
We thank the nurse and medical staff members of the critical care unit at Hospital Civil Fray Antonio Alcalde, and the patients and relatives for their participation. We also thank Dr. Luis Enrique Colunga Lozano, MD, MsC, (Department of Health Research Methods, Evidence and Impact. McMaster University. Hamilton, Ontario, Canada/ Department of intensive care medicine, Hospital Civil de Guadalajara “Dr. Juan I. Menchaca”. Guadalajara, Jalisco, México) for performing the Fine and Gray model with proportional hazards.