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.

Rapid fabrication of silk films with controlled architectures via electrogelation.

Current methods to produce silk films include casting and spin coating. Here we introduce a new method for the fabrication of silk films: electrogelation. Through use of a closed-loop anode, films with high surface smoothness and optical transparency are produced. Bending the electrode loop allows films with three-dimensional topologies to be formed, possessing thicknesses capable of descending into the submicron thin film regime.

Electronic sensor and actuator webs for large-area complex geometry cardiac mapping and therapy.

Curved surfaces, complex geometries, and time-dynamic deformations of the heart create challenges in establishing intimate, nonconstraining interfaces between cardiac structures and medical devices or surgical tools, particularly over large areas. We constructed large area designs for diagnostic and therapeutic stretchable sensor and actuator webs that conformally wrap the epicardium, establishing robust contact without sutures, mechanical fixtures, tapes, or surgical adhesives. These multifunctional web devices exploit open, mesh layouts and mount on thin, bio-resorbable sheets of silk to facilitate handling in a way that yields, after dissolution, exceptionally low mechanical moduli and thicknesses. In vivo studies in rabbit and pig animal models demonstrate the effectiveness of these device webs for measuring and spatially mapping temperature, electrophysiological signals, strain, and physical contact in sheet and balloon-based systems that also have the potential to deliver energy to perform localized tissue ablation.

Self-treatment: illicit buprenorphine use by opioid-dependent treatment seekers.

Outpatient-based opioid treatment (OBOT) with buprenorphine is an important treatment for people with opioid dependence. No quantitative empirical research has examined rationales for use of illicit buprenorphine by U.S. opioid-dependent treatment seekers. The current study sequentially screened OBOT admissions (n = 129) during a 6-month period in 2009. This study had two stages: (a) a cross-sectional epidemiological analysis of new intakes and existing patients already receiving a legal OBOT prescription (n = 78) and (b) a prospective longitudinal cohort design that followed 76% of the initial participants for 3 months of treatment (n = 42). The primary aims were to establish 2009 prevalence rates for illicit buprenorphine use among people seeking OBOT treatment, to use quantitative methods to investigate reasons for this illicit use, and to examine the effect of OBOT treatment on illicit buprenorphine use behavior. These data demonstrate a decrease in illicit use when opioid-dependent treatment seekers gain access to legal prescriptions. These data also suggest that the use of illicit buprenorphine rarely represents an attempt to attain euphoria. Rather, illicit use is associated with attempted self-treatment of symptoms of opioid dependence, pain, and depression.