Risk factors for decreased cardiac output after coronary artery bypass grafting: a prospective cohort study

Background: No previous study has investigated the predictive risk factors of the nursing diagnosis of risk for decreased cardiac output after coronary artery bypass grafting (CABG). Aims: This study aimed to identify the predictive risk factors of the nursing diagnosis of risk for decreased cardiac output after CABG. Methods: This was a prospective cohort study performed at a cardiac university hospital in São Paulo, Brazil and 257 adult patients undergoing CABG were included. Potential risk factors for low cardiac output in the immediate post-operative period were investigated using the patients’ medical records. Univariate analysis and logistic regression were used to identify the predictive risk factors of decreased cardiac output. The area under the receiver operating characteristic curve was calculated as a measure of accuracy. The variables that could not be analysed through logistic regression were analysed through Fisher’s exact test. Results: One hundred and ninety-five patients had low cardiac output in the immediate post-operative period. The predictive risk factors included age ⩾60 years, decreased left ventricle ejection fraction, not using the radial artery graft, positive fluid balance and post-operative arrhythmia that differed from the pre-operative arrhythmia. This model predicted the outcome with a sensitivity of 62.9%, a specificity of 87.2% and an accuracy of 81.5%. The variables analysed through Fisher’s exact test included heart failure, re-exploration and bleeding-related re-exploration. Conclusions: The predictive risk factors for the nursing diagnosis of risk for decreased cardiac output after CABG were found. These results can be used to direct nurses in patient monitoring, staff training and nursing team staffing.