title: Determinants of prolonged intensive care unit stay in patients after cardiac surgery: a prospective observational study.
abstract: BACKGROUND
  Prolonged intensive care unit (ICU) stay of patients after cardiac surgery has a major impact on overall cost and resource utilization. The aim of this study was to identify perioperative factors which prolong stay in ICU.
  
  
  METHODS
  All adult patients from a single, specialized cardiac center who were admitted to the ICU after cardiac surgery during a 2-month period were included. Demographic and clinical characteristics, comorbidities, preoperative use of drugs, intraoperative variables, and postoperative course were recorded. Hemodynamic and blood gas measurements were recorded at four time intervals during the first 24 postoperative hours. Routine hematologic and biochemical laboratory results were recorded preoperatively and in the first postoperative hours.
  
  
  RESULTS
  During the study period 145 adult patients underwent cardiac surgery: 65 (45%) underwent coronary artery bypass graft surgery, 38 (26%) valve surgery, 26 (18%) combined surgery and 16 (11%) other types of cardiac operation. Seventy nine (54%) patients had an ICU stay of less than 24 hours. Random forests analysis identified four variables that had a major impact on the length of stay (LOS) in ICU; these variables were subsequently entered in a logistic regression model: preoperative hemoglobin [odds ratio (OR) =0.68], duration of aortic clamping (OR =1.01) and ratio of arterial oxygen partial pressure to inspired oxygen fraction (PaO2/FiO2) (OR =0.99) and blood glucose during the first four postoperative hours (OR =1.02). ROC curve analysis showed an AUC =0.79, P<0.001, 95% CI: 0.71-0.86.
  
  
  CONCLUSIONS
  Low preoperative hemoglobin, prolonged aortic clamping time and low PaO2/FiO2ratio and blood glucose measured within the first postoperative hours, were strongly related with prolonged LOS in ICU.
authors.affiliation: Department of Nursing, Faculty of Health and Caring Professions, Technological Educational Institute of Athens, Athens, Greece.
authors.forename: Theodore
authors.initials: T
authors.lastname: Kapadohos
authors.affiliation: First Department of Intensive Care, School of Medicine, National and Kapodistrian University of Athens, Evangelismos Hospital, Athens, Greece.
authors.forename: Epameinondas
authors.initials: E
authors.lastname: Angelopoulos
authors.affiliation: Intensive Care Unit, First Department of Respiratory Medicine, School of Medicine, National and Kapodistrian University of Athens, Sotiria Hospital, Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vasileiadis
authors.affiliation: First Department of Intensive Care, School of Medicine, National and Kapodistrian University of Athens, Evangelismos Hospital, Athens, Greece.
authors.forename: Serafeim
authors.initials: S
authors.lastname: Nanas
authors.affiliation: First Department of Intensive Care, School of Medicine, National and Kapodistrian University of Athens, Evangelismos Hospital, Athens, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Kotanidou
authors.affiliation: Surgical Intensive Care Unit, Onassis Cardiac Surgery Center, Athens, Greece.
authors.forename: Andreas
authors.initials: A
authors.lastname: Karabinis
authors.affiliation: Surgical Intensive Care Unit, Onassis Cardiac Surgery Center, Athens, Greece.
authors.forename: Katerina
authors.initials: K
authors.lastname: Marathias
authors.affiliation: First Department of Intensive Care, School of Medicine, National and Kapodistrian University of Athens, Evangelismos Hospital, Athens, Greece.
authors.forename: Christina
authors.initials: C
authors.lastname: Routsi
keywords: Surgery; cardiovascular; heart; intensive care; risk