Risk factors associated with the onset of delirium in a post-operative cardiac surgical ICU

Abstract

Introduction Postoperative delirium is a disabling mental disorder in patients undergoing cardiac surgery. Post-cardiac surgery delirium is both a common and costly complication in the cardiac surgical ICU. Depending on the methodology, estimates of incidence have ranged from 3 to 70%. The potential consequences of delirium after cardiac surgery include increased morbidity, decreased functional status, cognitive decline and increased long-term mortality. Despite the impact of this condition, few studies exist in literature that help to identify risk factors associated with this condition in the specific setting of cardiac surgery. In this pilot, non-pharmacological, observational study we assessed the risk associated with the development of delirium in a cohort of patients who underwent cardiac surgery Methods We prospectively included 145 patients: women 42(28,9%) and 103men(71%) who underwent cardiac surgery between April and June 2018 at the cardiothoracic surgery department of the Tor Vergata University Hospital in Rome, Italy. Data about pre-intra and post-operatory period were collected. The presence of delirium was diagnosed if the CAM–ICU scale was positive when evaluated within the third post-operatory day. Univariate logistic regression was used to evaluate perioperative risk factors associated with delirium. Odds Ratio was used to estimate the importance of each factor in the genesis of delirium. Multivariate logistic regression was applied to the positive variables to assess the independent risk factors. A value p Results Among the 145 patients evaluated, 13 developed symptoms of delirium (5,09%). We found that the risk of Delirium was associated with pre-operatory EuroSCORE II (p = 0,028) and history of previous cardiac surgery (p = 0,042). Moreover, in the intra-operatory period the risk of Delirium was associated with red blood cell transfusion, intervention for Aortic Dissection (p = 0,013), HCA with ACP (p = 0,036). In the post-operatory period risk of Delirium was associated with levels of creatinine clearance (p = 0,035) and CRP (p = 0,029). Discussion Delirium is relatively frequent in the cardiac surgical ICU. High EuroScore correlates with the onset of delirium, suggesting that delirium is a multifactorial pathology linked with pre-operatory comorbidities. The complexity of surgery has a big influence on the development of delirium, especially in the cases of aortic dissection. Interestingly, the development of delirium was associated with intra-operatory blood transfusions in agreement with similar studies in literature. Finally, our data point to a bridge between post-operatory electrolytic disturbances, as well as inflammatory response to infections as factors potentially triggering delirium onset.