The Association Between Preoperative Frailty and Postoperative Delirium After Cardiac Surgery.

Delirium is common after cardiac surgery, and preoperative identification of high-risk patients could guide prevention strategies. We prospectively measured frailty in 55 patients before cardiac surgery and assessed postoperative delirium using a validated chart review. The prevalence of frailty was 30.9%. Frail patients had a higher incidence of delirium (47.1%) compared with nonfrail patients (2.6%; P < 0.001). In multivariable models, the relative risk of delirium was ≥2.1-fold greater in frail compared with nonfrail patients (relative risk, 18.3; 95% confidence interval, 2.1-161.8; P = 0.009). Frailty may identify patients who would benefit from delirium-prevention strategies because of increased baseline risk for delirium.

Blood Pressure Deviations From Optimal Mean Arterial Pressure During Cardiac Surgery Measured With a Novel Monitor of Cerebral Blood Flow and Risk for Perioperative Delirium: A Pilot Study.

OBJECTIVE: The aim of this study was to evaluate whether excursions of blood pressure from the optimal mean arterial pressure during and after cardiac surgery are associated with postoperative delirium identified using a structured examination. DESIGN: Prospective, observational study. SETTING: University hospital. PARTICIPANTS: The study included 110 patients undergoing cardiac surgery. INTERVENTIONS: Patients were monitored using ultrasound-tagged near-infrared spectroscopy to assess optimal mean arterial pressure by cerebral blood flow autoregulation monitoring during cardiopulmonary bypass and the first 3 hours in the intensive care unit. MEASUREMENTS AND MAIN RESULTS: The patients were tested preoperatively and on postoperative days 1 to 3 with the Confusion Assessment Method or Confusion Assessment Method for the Intensive Care Unit, the Delirium Rating Scale-Revised-98, and the Mini Mental State Examination. Summative presence of delirium on postoperative days 1 through 3, as defined by the consensus panel following Diagnostic and Statistical Manual of Mental Disorders-IV-TR criteria, was the primary outcome. Delirium occurred in 47 (42.7%) patients. There were no differences in blood pressure excursions above and below optimal mean arterial pressure between patients with and without summative presence of delirium. Secondary analysis showed blood pressure excursions above the optimal mean arterial pressure to be higher in patients with delirium (mean±SD, 33.2±26.51 mmHgxh v 23.4±16.13 mmHgxh; p = 0.031) and positively correlated with the Delirium Rating Scale score on postoperative day 2 (r = 0.27, p = 0.011). CONCLUSIONS: Summative presence of delirium was not associated with perioperative blood pressure excursions; but on secondary exploratory analysis, excursions above the optimal mean arterial pressure were associated with the incidence and severity of delirium on postoperative day 2.

Cerebral Autoregulation Monitoring with Ultrasound-Tagged Near-Infrared Spectroscopy in Cardiac Surgery Patients.

BACKGROUND: Individualizing mean arterial blood pressure (MAP) based on cerebral blood flow (CBF) autoregulation monitoring during cardiopulmonary bypass (CPB) holds promise as a strategy to optimize organ perfusion. The purpose of this study was to evaluate the accuracy of cerebral autoregulation monitoring using microcirculatory flow measured with innovative ultrasound-tagged near-infrared spectroscopy (UT-NIRS) noninvasive technology compared with transcranial Doppler (TCD). METHODS: Sixty-four patients undergoing CPB were monitored with TCD and UT-NIRS (CerOx™). The mean velocity index (Mx) was calculated as a moving, linear correlation coefficient between slow waves of TCD-measured CBF velocity and MAP. The cerebral flow velocity index (CFVx) was calculated as a similar coefficient between slow waves of cerebral flow index measured using UT-NIRS and MAP. When MAP is outside the autoregulation range, Mx is progressively more positive. Optimal blood pressure was defined as the MAP with the lowest Mx and CFVx. The right- and left-sided optimal MAP values were averaged to define the individual optimal MAP and were the variables used for analysis. RESULTS: The Mx for the left side was 0.31 ± 0.17 and for the right side was 0.32 ± 0.17. The mean CFVx for the left side was 0.33 ± 0.19 and for the right side was 0.35 ± 0.19. Time-averaged Mx and CFVx during CPB had a statistically significant "among-subject" correlation (r = 0.39; 95% confidence interval [CI], 0.22-0.53; P < 0.001) but had only a modest agreement within subjects (bias 0.03 ± 0.20; 95% prediction interval for the difference between Mx and CFVx, -0.37 to 0.42). The MAP with the lowest Mx and CFVx ("optimal blood pressure") was correlated (r = 0.71; 95% CI, 0.56-0.81; P < 0.0001) and was in modest within-subject agreement (bias -2.85 ± 8.54; 95% limits of agreement for MAP predicted by Mx and CFVx, -19.60 to 13.89). Coherence between ipsilateral middle CBF velocity and cerebral flow index values averaged 0.61 ± 0.07 (95% CI, 0.59-0.63). CONCLUSIONS: There was a statistically significant correlation and agreement between CBF autoregulation monitored by CerOx compared with TCD-based Mx.

Effect of Targeting Mean Arterial Pressure During Cardiopulmonary Bypass by Monitoring Cerebral Autoregulation on Postsurgical Delirium Among Older Patients: A Nested Randomized Clinical Trial.

Importance: Delirium occurs in up to 52% of patients after cardiac surgery and may result from changes in cerebral perfusion. Using intraoperative cerebral autoregulation monitoring to individualize and optimize cerebral perfusion may be a useful strategy to reduce the incidence of delirium after cardiac surgery. Objective: To determine whether targeting mean arterial pressure during cardiopulmonary bypass (CPB) using cerebral autoregulation monitoring reduces the incidence of delirium compared with usual care. Design, Setting, and Participants: This randomized clinical trial nested within a larger trial enrolled patients older than 55 years who underwent nonemergency cardiac surgery at a single US academic medical center between October 11, 2012, and May 10, 2016, and had a high risk for neurologic complications. Patients, physicians, and outcome assessors were masked to the assigned intervention. A total of 2764 patients were screened, and 199 were eligible for analysis in this study. Intervention: In the intervention group, the patient's lower limit of cerebral autoregulation was identified during surgery before CPB. On CPB, the patient's mean arterial pressure was targeted to be greater than that patient's lower limit of autoregulation. In the control group, mean arterial pressure targets were determined according to institutional practice. Main Outcomes and Measures: The main outcome was any incidence of delirium on postoperative days 1 through 4, as adjudicated by a consensus expert panel. Results: Among the 199 participants in this study, mean (SD) age was 70.3 (7.5) years and 150 (75.4%) were male. One hundred sixty-two (81.4%) were white, 26 (13.1%) were black, and 11 (5.5%) were of other race. Of 103 patients randomized to usual care, 94 were analyzed, and of 102 patients randomized to the intervention 105 were analyzed. Excluding 5 patients with coma, delirium occurred in 48 of the 91 patients (53%) in the usual care group compared with 39 of the 103 patients (38%) in the intervention group (P = .04). The odds of delirium were reduced by 45% in patients randomized to the autoregulation group (odds ratio, 0.55; 95% CI, 0.31-0.97; P = .04). Conclusions and Relevance: The results of this study suggest that optimizing mean arterial pressure to be greater than the individual patient's lower limit of cerebral autoregulation during CPB may reduce the incidence of delirium after cardiac surgery, but further study is needed. Trial Registration: ClinicalTrials.gov identifier: NCT00981474.

Altered cortical brain activity in end stage liver disease assessed by multi-channel near-infrared spectroscopy: Associations with delirium.

Delirium is a common and serious psychiatric syndrome caused by an underlying medical condition. It is associated with significant mortality and increased healthcare resource utilization. There are few biological markers of delirium, perhaps related to the etiologic heterogeneity of the syndrome. Functional near-infrared spectroscopy (fNIRS) is an optical topography system to measure changes in the concentration of oxygenated hemoglobin ([oxy-Hb]) in the cerebral cortex. We examined whether altered cortical brain activity in delirious patients with end stage liver disease (ESLD) is detected by fNIRS. We found that the [oxy-Hb] change during the verbal fluency task (VFT) was reduced in patients with ESLD compared with healthy controls (HC) in the prefrontal and bi-temporal regions. The [oxy-Hb] change during the sustained attention task (SAT) was elevated in patients with ESLD compared to HC in the prefrontal and left temporal regions. Notably, [oxy-Hb] change in the left dorsolateral prefrontal cortex during SAT showed a positive correlation with the severity of delirium. Our results suggest that [oxy-Hb] change in the prefrontal cortex during the sustained attention task measured with fNIRS might serve as a biological marker associated with delirium in ESLD patients.

The Impact of Delirium After Cardiac Surgical Procedures on Postoperative Resource Use.

BACKGROUND: Delirium is a common complication after cardiac surgical procedures and is associated with increased morbidity and mortality. However, whether rigorously assessed postoperative delirium is associated with an increased length of stay in the intensive care unit (LOS-ICU), length of stay (LOS), and hospital charges is not clear. METHODS: Patients (n = 66) undergoing coronary artery bypass or valve operations, or both, were enrolled in a nested cohort study. Rigorous delirium assessments were conducted using the Confusion Assessment Method. LOS-ICU and LOS were obtained from the medical record, and hospital charges were obtained from administrative data reported to the state. Because of the skewed distribution of outcome variables, outcomes were compared using rank-sum tests, as well as median regression incorporating propensity scores. RESULTS: Patients who developed delirium (56%) versus no delirium (43%) had increased median LOS-ICU (75.6 hours [interquartile range (IQR): 43.6 to 136.8] vs. 29.7 hours [IQR: 21.7 to 46.0]; p = 0.002), increased median LOS (9 days [IQR: 6 to 16] vs. 7 days [IQR: 5 to 8]; p = 0.006), and increased median hospital charges ($51,805 [IQR: $44,041 to $80,238] vs. $41,576 [IQR: $35,748 to $43,660]; p = 0.002). In propensity score models adjusted for patient-related and surgical characteristics and complications, the results for LOS-ICU and cost remained highly significant, although the results for LOS were attenuated on the basis of the specific statistical model. Increased severity of delirium was associated with both increased LOS-ICU and increased charges in a dose-response manner. CONCLUSIONS: Delirium after cardiac surgical procedures is independently associated with both increased LOS-ICU and higher hospital charges. Because delirium is potentially preventable, targeted delirium-prevention protocols for high-risk patients may represent an important strategy for quality improvement.

Perioperative optimal blood pressure as determined by ultrasound tagged near infrared spectroscopy and its association with postoperative acute kidney injury in cardiac surgery patients.

OBJECTIVES: Perioperative blood pressure management by targeting individualized optimal blood pressure, determined by cerebral blood flow autoregulation monitoring, may ensure sufficient renal perfusion. The purpose of this study was to evaluate changes in the optimal blood pressure for individual patients, determined during cardiopulmonary bypass (CPB) and during early postoperative period in intensive care unit (ICU). A secondary aim was to examine if excursions below optimal blood pressure in the ICU are associated with risk of cardiac surgery-associated acute kidney injury (CSA-AKI). METHODS: One hundred and ten patients undergoing cardiac surgery had cerebral blood flow monitored with a novel technology using ultrasound tagged near infrared spectroscopy (UT-NIRS) during CPB and in the first 3 h after surgery in the ICU. The correlation flow index (CFx) was calculated as a moving, linear correlation coefficient between cerebral flow index measured using UT-NIRS and mean arterial pressure (MAP). Optimal blood pressure was defined as the MAP with the lowest CFx. Changes in optimal blood pressure in the perioperative period were observed and the association of blood pressure excursions (magnitude and duration) below the optimal blood pressure [area under the curve (AUC) < OptMAP mmHgxh] with incidence of CSA-AKI (defined using Kidney Disease: Improving Global Outcomes criteria) was examined. RESULTS: Optimal blood pressure during early ICU stay and CPB was correlated (r = 0.46, P < 0.0001), but was significantly higher in the ICU compared with during CPB (75 ± 8.7 vs 71 ± 10.3 mmHg, P = 0.0002). Thirty patients (27.3%) developed CSA-AKI within 48 h after the surgery. AUC < OptMAP was associated with CSA-AKI during CPB [median, 13.27 mmHgxh, interquartile range (IQR), 4.63-20.14 vs median, 6.05 mmHgxh, IQR 3.03-12.40, P = 0.008], and in the ICU (13.72 mmHgxh, IQR 5.09-25.54 vs 5.65 mmHgxh, IQR 1.71-13.07, P = 0.022). CONCLUSIONS: Optimal blood pressure during CPB and in the ICU was correlated. Excursions below optimal blood pressure (AUC < OptMAP mmHgXh) during perioperative period are associated with CSA-AKI. Individualized blood pressure management based on cerebral autoregulation monitoring during the perioperative period may help improve CSA-AKI-related outcomes.

Delirium After Spine Surgery in Older Adults: Incidence, Risk Factors, and Outcomes.

OBJECTIVES: To characterize the incidence, risk factors, and consequences of delirium in older adults undergoing spine surgery. DESIGN: Prospective observational study. SETTING: Academic medical center. PARTICIPANTS: Individuals aged 70 and older undergoing spine surgery (N = 89). MEASUREMENTS: Postoperative delirium and delirium severity were assessed using validated methods, including the Confusion Assessment Method (CAM), CAM for the Intensive Care Unit, Delirium Rating Scale-Revised-98, and chart review. Hospital-based outcomes were obtained from the medical record and hospital charges from data reported to the state. RESULTS: Thirty-six participants (40.5%) developed delirium after spine surgery, with 17 (47.2%) having purely hypoactive features. Independent predictors of delirium were lower baseline cognition, higher average baseline pain, more intravenous fluid administered, and baseline antidepressant medication. In adjusted models, the development of delirium was independently associated with higher quintile of length of stay (odds ratio (OR) = 3.66, 95% confidence interval (CI) = 1.48-9.04, P = .005), higher quintile of hospital charges (OR = 3.49, 95% CI = 1.35-9.00, P = .01), and lower odds of discharge to home (OR = 0.22, 95% CI = 0.07-0.69, P = .009). Severity of delirium was associated with higher quintile of hospital charges and lower odds of discharge to home. CONCLUSION: Delirium is common after spine surgery in older adults, and baseline pain is an independent risk factor. Delirium is associated with longer stay, higher charges, and lower odds of discharge to home. Thus, prevention of delirium after spine surgery may be an important quality improvement goal.

The Association of Brain MRI Characteristics and Postoperative Delirium in Cardiac Surgery Patients.

PURPOSE: Delirium is common after cardiac surgery and is associated with adverse consequences, including cognitive decline. Identification of vulnerable older adults might allow for early implementation of delirium-prevention strategies. Brain MRI findings provide insight into structural brain changes that may identify vulnerable patients. The purpose of this study was to examine the association between brain MRI characteristics potentially associated with delirium vulnerability and the development of postoperative delirium in a nested cohort of patients undergoing cardiac surgery. METHODS: We identified 79 cardiac surgery patients who had brain MRI imaging after cardiac surgery, as part of an ongoing randomized trial evaluating the efficacy of blood pressure management based on cerebral autoregulation monitoring versus standard management for improving neurological outcomes. Cerebral lateral ventricular size, cortical sulcal width, and white matter hyperintensities (WMH) on brain MRI scans were graded on a validated 0 to 9 scale, and categorized into tertiles. New ischemic lesions were characterized as present or absent. Delirium was assessed using a validated chart-review. Neuropsychological testing performed before surgery was used to establish preoperative cognitive baseline. Multivariable logistic regression was used to assess the independent association between MRI characteristics and postoperative delirium. FINDINGS: The average age of patients was 70.1 ± 7.8 years old, and 72% were male. Twenty-eight of 79 (35.4%) patients developed postoperative delirium. Patients with delirium had higher unadjusted ventricular size (median 4 vs. 3, P = 0.003), and there was a trend towards higher sulcal sizes and WMH grades. Increasing tertiles of ventricular size (Odds Ratio [OR] 3.59; 95% Confidence Interval [CI] 1.59-8.12; P = 0.002) and sulcal size (OR 2.15; 95%CI 1.13-4.12; P = 0.02) were associated with postoperative delirium, with a trend for tertiles of WMH grade (OR 1.91; 95%CI 0.99-3.68; P = 0.05). In multivariable models adjusted for logistic EuroSCORE, baseline cognitive status, bypass time, and any postoperative complication, each tertile of ventricular size was associated with increased odds of postoperative delirium (OR 3.23 per tertile increase in ventricular size; 95%CI 1.21-8.60; P = 0.02). There were no differences in odds of delirium by tertiles of sulcal grade, tertiles of white matter grade, or presence of new ischemic lesions, in adjusted models. IMPLICATIONS: Increased brain ventricular size was independently associated with delirium after cardiac surgery. These results suggest that cerebral atrophy may contribute to increased vulnerability for postoperative delirium. Baseline brain MRIs may be useful in identifying cardiac surgery patients at high risk for postoperative delirium, who might benefit from targeted perioperative approaches to prevent delirium. ClinicalTrials.gov identifier: NCT00981474.

Impaired olfaction and risk of delirium or cognitive decline after cardiac surgery.

OBJECTIVES: To determine the prevalence of impaired olfaction in individuals presenting for cardiac surgery and the independent association between impaired olfaction and postoperative delirium and cognitive decline. DESIGN: Nested prospective cohort study. SETTING: Academic hospital. PARTICIPANTS: Individuals undergoing coronary artery bypass, valve surgery, or both (n = 165). MEASUREMENTS: Olfaction was measured using the Brief Smell Identification Test, with impaired olfaction defined as an olfactory score below the fifth percentile of normative data. Delirium was assessed using a validated chart review method. Cognitive performance was assessed using a neuropsychological testing battery at baseline and 4 to 6 weeks after surgery. RESULTS: Impaired olfaction was identified in 54 of 165 participants (33%) before surgery. Impaired olfaction was associated with greater adjusted risk of postoperative delirium (relative risk = 1.90, 95% confidence interval = 1.17-3.09, P = .009). There was no association between impaired olfaction and change in composite cognitive score in the overall study population. CONCLUSION: Impaired olfaction is prevalent in individuals undergoing cardiac surgery and is associated with greater adjusted risk of postoperative delirium but not cognitive decline. Impaired olfaction may identify unrecognized vulnerability to postoperative delirium in individuals undergoing cardiac surgery.

Basal salivary oxytocin level predicts extra- but not intra-personal dimensions of emotional intelligence.

A wealth of literature suggests that oxytocin is an important mediator of social cognition, but much of the research to date has relied on pharmaceutical administration methods that can raise oxytocin to artificially high levels. The present study builds upon previous work by examining whether basal oxytocin level predicts intra- and extra-personal (i.e., self- and other-focused) elements of emotional intelligence (EI), independent of shared variance with current mood. The sample included 71 healthy young adults (46 women). Assessment measures included the Mayer-Salovey-Caruso Emotional Intelligence Test Version 2.0 (MSCEIT), the Trait Meta-Mood Scale, and the Profile of Mood States. Peripheral oxytocin levels were examined with enzyme-linked immunosorbent assay from saliva after solid phase extraction. Oxytocin level was unrelated to TMMS scores but was positively associated with performance in the Experiential EI domain of the MSCEIT. However, total mood disturbance was positively related to MSCEIT scores. Hierarchical regression analysis indicated that oxytocin level added unique variance to the prediction of MSCEIT performance beyond that of current mood. These results confirm an association between endogenous levels of oxytocin in healthy adults and a subset of EI abilities, including extra-personal emotion recognition and the channeling of emotions to enhance social proficiency.