Delirium After Cardiac Surgery and Cumulative Fluid Balance: A Case-Control Cohort Study.

OBJECTIVE: To assess a novel hypothesis to explain delirium after cardiac surgery through the relationship between cumulative fluid balance and delirium. This hypothesis involved an inflammatory process combined with a hypervolemic state, which could lead to venous congestion reaching the brain. DESIGN: Retrospective case-control (1:1) cohort study. SETTING: University-affiliated tertiary cardiology center. PARTICIPANTS: Cardiac surgery intensive care unit (ICU) patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Cumulative fluid balance was evaluated at 3 times: (1) upon arrival at the ICU after surgery, (2) 24 hours post-ICU arrival, and (3) 48 hours post-ICU arrival. A generalized estimated equation was used to model the association between cumulative fluid balance and delirium occurrence 24 hours later. Covariates were selected based on the statistical differences between cases and controls on delirium risk factors and clinical characteristics. The cohort included 346 patients, of which 39 (11%), 104 (30%), and 142 patients (41%) presented delirium at 24, 48, and 72 hours post-ICU arrival, respectively. The effect of time had an odds ratio (OR) of 2.14, 95% confidence interval (CI) 1.603 to 2.851, and a p value < 0.001. The cumulative fluid balance was associated with delirium occurrence (OR 1.20, 95% CI: 1.066-1.355, p = .003). History of neurological disorder, having both hearing and visual impairment, type of procedure, perioperative cerebral oximetry, mean pulmonary artery pressure pre-cardiopulmonary bypass (CPB), and mean arterial pressure post-CPB also contributed to delirium in the model. CONCLUSION: Delirium is associated with a cumulative fluid balance, but the extent through which this plays an etiologic role remains to be determined.

Portal Hypertension Is Associated With Congestive Encephalopathy and Delirium After Cardiac Surgery.

BACKGROUND: Venous congestion might lead to congestive encephalopathy after cardiac surgery. However, objective signs of congestion have yet to be associated with delirium. Portal vein flow pulsatility is a congestion marker that may identify a subgroup of patients at risk. METHODS: We performed a retrospective study and a prospective study in patients undergoing cardiac surgery. Adult patients who underwent portal vein Doppler imaging by the attending physician during usual care in the intensive care unit were included in the retrospective cohort. For the prospective cohort, patients had a cognitive and echocardiographic evaluation the day before surgery and daily for 3 days after surgery. Delirium was independently assessed by the nursing staff in the prospective cohort. RESULTS: A total of 237 patients in the retrospective cohort and 145 patients in the prospective cohort were included, for whom 1074 portal Doppler evaluations were performed. An association was found between delirium and portal vein pulsatility in the retrospective cohort (odds ratio [OR], 2.69; confidence interval [CI], 1.47-4.90; P = 0.001). In the prospective cohort, significant associations were found between the presence of portal vein pulsatility and the development of cognitive dysfunction and asterixis assessed by the investigators (OR, 2.10; CI, 1.25-3.53; P = 0.005 and OR, 2.23; CI, 1.13; 4.41; P = 0.02, and delirium detected by the nursing staff (hazard ratio, 2.63; CI, 1.13-6.11; P = 0.025). Higher N-terminal pro-beta natriuretic peptide measurements (OR, 4.03; CI, 1.78-9.15; P = 0.001) and cerebral desaturations (OR, 2.54; CI, 1.12-5.76; P = 0.03) were associated with cognitive dysfunction. CONCLUSION: These data present an association among hepatic congestion, delirium, and encephalopathy in patients undergoing cardiac surgery. Further studies should explore whether those neurological complications may have a congestive origin in some patients.

Alterations in Portal Vein Flow and Intrarenal Venous Flow Are Associated With Acute Kidney Injury After Cardiac Surgery: A Prospective Observational Cohort Study.

Background Acute kidney injury ( AKI ) after cardiac surgery is associated with adverse outcomes. Venous congestion can impair kidney function, but few tools are available to assess its impact at the bedside. The objective of this study was to determine whether portal flow pulsatility and alterations in intrarenal venous flow assessed by Point-Of-Care ultrasound are associated with AKI after cardiac surgery. Methods and Results This single-center prospective cohort study recruited patients undergoing cardiac surgery with cardiopulmonary bypass. Hepatic and renal Doppler ultrasound assessments were performed before surgery, at the intensive care unit admission, and daily for 3 days after surgery. The primary statistical analysis was performed using proportional hazards model for time-dependent variables. Among the 145 patients included, 49 patients (33.8%) developed AKI after cardiac surgery. The detection of portal flow pulsatility was associated with an increased risk of AKI (hazard ratio: 2.09, confidence interval, 1.11-3.94, P=0.02), as were severe alterations of intrarenal venous flow (hazard ratio: 2.81, confidence interval, 1.42-5.56, P=0.003). These associations remained significant in multivariable models. The addition of these markers to preoperative risk factors and central venous pressure measurement at intensive care unit admission improved the prediction of AKI . (Continuous net reclassification improvement: 0.364, confidence interval, 0.081-0.652 for portal Doppler and net reclassification improvement: 0.343, confidence interval, 0.081-0.628 for intrarenal Doppler) Conclusions Portal flow pulsatility and intrarenal flow alterations are markers of venous congestion and are independently associated with AKI after cardiac surgery. These tools might offer valuable information to develop strategies aimed at treating or preventing congestive cardiorenal syndrome after cardiac surgery. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT 02831907.