Prediction of Prolonged ICU Stay in Cardiac Surgery Patients as a Useful Method to Identify Nutrition Risk in Cardiac Surgery Patients: A Post Hoc Analysis of a Prospective Observational Study

Abstract

Background: Cardiovascular surgery patients with a prolonged intensive care unit (ICU) stay may benefit most from early nutrition support. Using established scoring systems for nutrition assessment and operative risk stratification, we aimed to develop a model to predict a prolonged ICU stay ≥5 days in order to identify patients who will benefit from early nutrition interventions.

Methods: This is a retrospective analysis of a prospective observational study of patients undergoing elective valvular, coronary artery bypass grafting, or combined cardiac surgery. The nutrition risk was assessed by well-established screening tools. Patients' preoperative EuroSCORE (European System for Cardiac Operative Risk Evaluation), primary disease, and intraoperative cardiopulmonary bypass (CPB) time were included as independent variables in a multivariate logistic regression analysis to predict a prolonged ICU stay (>4 days).

Results: The number of cardiac surgery patients included was 1193. Multivariate analysis revealed that for prediction of ICU stay >4 days, both Nutritional Risk Screening 2002 (area under the curve (AUC): 0.716, P = .020) and Mini Nutritional Assessment (MNA) score (AUC: 0.715, P = .037) were significant, whereas for prediction of ICU stay >5 days, only the MNA score showed significant results (AUC: 0.762, P = .011).

Conclusion: Present data provide first evidence about the combined use of EuroSCORE, primary disease, CPB time, and nutrition risk screening tools for prediction of prolonged ICU stay in cardiac surgery patients. If prospectively evaluated in adequately designed studies, this model may help to identify patients with prolonged ICU stay to initiate early postoperative nutrition therapy and thus, facilitate an enhanced recovery.

Keywords: ICU stay; cardiac disease; cardiac surgery; nutrition; nutrition assessment; nutrition screening tools; nutrition support practice; outcomes quality; outcomes research; parenteral nutrition; prediction model; research and diseases.

Figure 1

Conceptual model to identify patients with prolonged ICU stay and adapt ICU nutrition management accordingly. CK‐MB, creatine kinase MB; CPB, cardiopulmonary bypass; CRP, C‐reactive protein; EuroSCORE, European System for Cardiac Operative Risk Evaluation; ICU, intensive care unit; IL, interleukin; MNA, Mini Nutritional Assessment; NRS‐2002, Nutritional Risk Screening 2002; PCT, procalcitonin; TNF, tumor necrosis factor.

Figure 2

ROC curves for selected models including NRS‐2002 for prediction of ICU stay >4 and >5 days. CPB, cardiopulmonary bypass; EuroSCORE, European System for Cardiac Operative Risk Evaluation; ICU, intensive care unit; NRS‐2002, Nutritional Risk Screening 2002; PrimPath, primary pathology; ROC, receiver operating characteristic. P: Wald χ² test; significant values (P < .05) are depicted in bold.

Figure 3

ROC curves for predicting ICU stay >5 days by underlying pathology, including nutrition parameters, EuroSCORE, and CPB time. CAD, coronary artery disease; CPB, cardiopulmonary bypass; EuroSCORE, European System for Cardiac Operative Risk Evaluation; HVD, heart valvular disease; MNA, Mini Nutritional Assessment; NRS‐2002, Nutritional Risk Screening 2002; ROC, receiver operating characteristic. P: Wald χ² test; significant values (P < .05) are depicted in bold.

Figure 3

ROC curves for predicting ICU stay >5 days by underlying pathology, including nutrition parameters, EuroSCORE, and CPB time. CAD, coronary artery disease; CPB, cardiopulmonary bypass; EuroSCORE, European System for Cardiac Operative Risk Evaluation; HVD, heart valvular disease; MNA, Mini Nutritional Assessment; NRS‐2002, Nutritional Risk Screening 2002; ROC, receiver operating characteristic. P: Wald χ² test; significant values (P < .05) are depicted in bold.

Figure 4

Schematic illustration of perioperative risk factors for a prolonged ICU stay of cardiac surgery patients. The figure depicts the perioperative variable, which should be considered to estimate an increased risk for a prolonged ICU stay (CPB time >108 min, EuroSCORE >9, nutrition risk should be assessed with MNA). CPB, cardiopulmonary bypass; EuroSCORE, European System for Cardiac Operative Risk Evaluation; ICU, intensive care unit; MNA, Mini Nutritional Assessment.