Objectives: Following cardiac surgery, a great variety in intensive care unit (ICU) stay is observed, making it often difficult to adequately predict ICU-stay preoperatively. Therefore, a study was conducted to investigate which preoperative variables are independent risk factors for a prolonged ICU-stay and whether the probable ICU-stay of an individual can be derived from these predictors.
Methods: The records of 1566 consecutive adult patients who underwent cardiac surgery at our institution were analyzed retrospectively over a two-year period from January 1, 2005 until December 31, 2006. Procedures included in the analyses were CABG, valve replacement or repair, ascending and aortic arch surgery, ventricular rupture and aneurysm repair, cardiac tumors and congenital septal defects. For this patient group, ICU-stay was registered and 57 preoperative variables were collected for analysis. Descriptives and log-rank tests were calculated and Kaplan-Meier curves drawn for all variables. Significant predictors in the univariate analyses were included in a Cox proportional hazards model.
Results: Twelve independent preoperative predictors of prolonged ICU-stay were identified: increased age, female gender, dyspnea status > NYHA II, unstable symptoms, elevated serum creatinine, extra-cardiac arterial disease, presence of arrhythmias, mitral insufficiency > CFM grade II, inotropic support, intra-aortic balloon pumping (IABP), non-elective procedures and aortic surgery. The individual effect of every predictor on ICU-stay was quantified (see table 1).
Conclusions: Twelve independent preoperative risk factors for a prolonged ICU-stay following cardiac surgery were identified and constructed into a mathematical proportional hazards model. This is the first model to preoperatively calculate the probable ICU-stay.
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