Delirium and frailty in older adults: Clinical overlap and biological underpinnings.

Frailty and delirium are two common geriatric syndromes sharing several clinical characteristics, risk factors, and negative outcomes. Understanding their interdependency is crucial to identify shared mechanisms and implement initiatives to reduce the associated burden. This literature review summarizes scientific evidence on the complex interplay between frailty and delirium; clinical, epidemiological, and pathophysiological commonalities; and current knowledge gaps. We conducted a PubMed systematic search in June 2023, which yielded 118 eligible articles out of 991. The synthesis of the results-carried out by content experts-highlights overlapping risk factors, clinical phenotypes, and outcomes and explores the influence of one syndrome on the onset of the other. Common pathophysiological mechanisms identified include inflammation, neurodegeneration, metabolic insufficiency, and vascular burden. The review suggests that frailty is a risk factor for delirium, with some support for delirium associated with accelerated frailty. The proposed unifying framework supports the integration and measurement of both constructs in research and clinical practice, identifying the geroscience approach as a potential avenue to develop strategies for both conditions. In conclusion, we suggest that frailty and delirium might be alternative-sometimes coexisting-manifestations of accelerated biological aging. Clinically, the concepts addressed in this review can help approach older adults with either frailty or delirium from a different perspective. From a research standpoint, longitudinal studies are needed to explore the hypothesis that specific pathways within the biology of aging may underlie the clinical manifestations of frailty and delirium. Such research will pave the way for future understanding of other geriatric syndromes as well.

Clinician perspectives on the perioperative roles and responsibilities of anesthesia, surgery, and primary care.

BACKGROUND: Although high-risk older patients benefit from a multidisciplinary approach to perioperative care, the specific roles and responsibilities of the clinicians involved have yet to be adequately characterized. METHODS: Qualitative analysis of semi-structured interviews with four anesthesia preoperative clinic providers, seven surgeons, and nine primary care providers in northern New England. RESULTS: The analysis revealed both distinct and overlapping roles and responsibilities. Anesthesia providers were described as a "safety net" and surgeons as "captain of the ship", in charge of getting "all the ducks in a row" to avoid surgery delays and cancellations. Primary care providers saw themselves as the "quarterback", ensuring care continuity and consideration of patient psychosocial factors. CONCLUSIONS: While all have a shared responsibility for facilitating patient-centered decision-making and a safe perioperative course, each discipline has different areas of focus and expertise. Role clarification can help optimize the distribution of responsibilities and enhance perioperative communication and collaboration.

Administration of the American Board of Anesthesiology's virtual APPLIED Examination: successes, challenges, and lessons learned.

In response to the COVID-19 pandemic, the American Board of Anesthesiology transitioned from in-person to virtual administration of its APPLIED Examination, assessing more than 3000 candidates for certification purposes remotely in 2021. Four hundred examiners were involved in delivering and scoring Standardized Oral Examinations (SOEs) and Objective Structured Clinical Examinations (OSCEs). More than 80% of candidates started their exams on time and stayed connected throughout the exam without any problems. Only 74 (2.5%) SOE and 45 (1.5%) OSCE candidates required rescheduling due to technical difficulties. Of those who experienced "significant issues", concerns with OSCE technical stations (interpretation of monitors and interpretation of echocardiograms) were reported most frequently (6% of candidates). In contrast, 23% of examiners "sometimes" lost connectivity during their multiple exam sessions, on a continuum from minor inconvenience to inability to continue. 84% of SOE candidates and 89% of OSCE candidates described "smooth" interactions with examiners and standardized patients/standardized clinicians, respectively. However, only 71% of SOE candidates and 75% of OSCE candidates considered themselves to be able to demonstrate their knowledge and skills without obstacles. When compared with their in-person experiences, approximately 40% of SOE examiners considered virtual evaluation to be more difficult than in-person evaluation and believed the remote format negatively affected their development as an examiner. The virtual format was considered to be less secure by 56% and 40% of SOE and OSCE examiners, respectively. The retirement of exam materials used virtually due to concern for compromise had implications for subsequent exam development. The return to in-person exams in 2022 was prompted by multiple factors, especially concerns regarding standardization and security. The technology is not yet perfect, especially for testing in-person communication skills and displaying dynamic exam materials. Nevertheless, the American Board of Anesthesiology's experience demonstrated the feasibility of conducting large-scale, high-stakes oral and performance exams in a virtual format and highlighted the adaptability and dedication of candidates, examiners, and administering board staff.

Implementation of a Multidisciplinary Team to Improve the Quality of Care for Older Surgical Patients at a Rural Academic Medical Center.

For the first time in history, people age older than 65 years make up >20% of the non-metro population, compared with 16% of the metro population. From 2010 to 2020 the nonmetro population age older than 65 years grew by 22%, while the working-age population declined by 4.9%, and the population aged under 18 years declined by 5.7%.1,2 Multidisciplinary geriatric surgical programs are an increasingly recognized approach to the care of older surgical patients and preliminary data suggest they can reduce length of stay. Although rural areas have the greatest proportion of patients age older than 65 years, implementation of such programs faces special challenges in rural settings with limited resources. Dartmouth-Hitchcock Medical Center is one of the most rural academic centers in the United States. Challenges include a shortage of geriatric-trained providers, long distances to access primary care and subspecialists, and extremely limited postacute care options and skilled nursing facility beds. To address the unique needs of our provider and patient population we began with a development period where we conducted stakeholder interviews. Using these data, we mapped out a workflow and developed pilot projects to address different portions of the workflow, such as preoperative screening for frailty and cognitive impairment, interdisciplinary weekly case conferences, proactive case management, delirium and geriatric surgery postoperative pathway order sets, and a variety of tools for reorientation and delirium management. Herein we describe the process of development and pragmatic clinical implementation of geriatric-focused care for older surgical patients in our rural tertiary center, including some of the main challenges we faced and the strategies we undertook to overcome them, and some of our early patient centered and clinical outcomes. This information may assist other institutions as they design geriatric-focused surgical programs to address the growing population of older adults and the need for compliance with state legislation. The clinical program described is not a research study, and the outcome data we report is for the purpose of description, and should not be interpreted as a rigorous research investigation of the effect of our intervention.

Perioperative Primary Care Utilization and Postoperative Readmission, Emergency Department Use, and Mortality in Older Surgical Patients.

BACKGROUND: Postdischarge primary care follow-up is associated with lower readmission rates after medical hospitalizations. However, the effect of primary care utilization on readmission has not been studied in surgical patients. METHODS: Retrospective cohort study of Medicare beneficiaries aged 65 and older undergoing major inpatient diagnostic or therapeutic procedures (n = 3,552,906) from 2017 through 2018, examining the association between postdischarge primary care visits within 14 days of discharge (primary exposure), and Annual Wellness Visits in the year prior (secondary exposure), with 30-day unplanned readmission (primary outcome), emergency department visits, and mortality (secondary outcomes). RESULTS: Overall, 9.5% (n = 336,837) had postdischarge visits within 14 days, 2.9% (n = 104,571) had Annual Wellness Visits in the year preceding the procedure, 9.5% (n = 336,401) were readmitted, 9% (n = 319,054) had emergency department visits, and 0.6% (n = 22,103) of the cohort died within 30 days. Our fully adjusted propensity-matched proportional hazards Cox regression analysis showed that postdischarge visits were associated with a 5% lower risk of readmission (hazard ratio [HR], 0.95, 95% confidence interval [CI], 0.93-0.97), 43% higher risk of emergency department use (HR, 1.43, 95% CI, 1.40-1.46) and no difference in mortality risk (HR, 0.98, 95% CI, 0.90-1.06), compared with not having a visit within 14 days of discharge. In a separate set of regression models, Annual Wellness Visits were associated with a 9% lower risk of readmission (HR, 0.91, 95% CI, 0.88-0.95), 45% higher risk of emergency department utilization (HR, 1.45, 95% CI, 1.40-1.49) and an 18% lower mortality risk (HR, 0.82, 95% CI, 0.75-0.89) compared with no Annual Wellness Visit in the year before the procedure. CONCLUSIONS: Both postdischarge visits and the Medicare Annual Wellness Visit appear to be extremely underutilized among the older surgical population. In those patients who do utilize primary care, compared with propensity-matched patients who do not, our study suggests primary care use is associated with modestly lower readmission rates. Prospective studies are needed to determine whether targeted primary care involvement can reduce readmission.

A Comparison of Psychometric Properties of the American Board of Anesthesiology's In-Person and Virtual Standardized Oral Examinations.

PURPOSE: The COVID-19 pandemic prompted training institutions and national credentialing organizations to administer examinations virtually. This study compared task difficulty, examiner grading, candidate performance, and other psychometric properties between in-person and virtual standardized oral examinations (SOEs) administered by the American Board of Anesthesiology. METHOD: This retrospective study included SOEs administered in person from March 2018 through March 2020 and virtually from December 2020 through November 2021. The in-person and virtual SOEs share the same structure, including 4 tasks of preoperative evaluation, intraoperative management, postoperative care, and additional topics. The Many-Facet Rasch Model was used to estimate candidate performance, examiner grading severity, and task difficulty for the in-person and virtual SOEs separately; the virtual SOE was equated to the in-person SOE by common examiners and all tasks. The independent-samples and partially overlapping-samples t tests were used to compare candidate performance and examiner grading severity between these 2 formats, respectively. RESULTS: In-person (n = 3,462) and virtual (n = 2,959) first-time candidates were comparable in age, sex, race and ethnicity, and whether they were U.S. medical school graduates. The mean (standard deviation [SD]) candidate performance was 2.96 (1.76) logits for the virtual SOE, which was statistically significantly better than that for the in-person SOE (mean [SD], 2.86 [1.75]; Welch independent-samples t test, P = .02); however, the effect size was negligible (Cohen d = 0.06). The difference in the grading severity of examiners who rated the in-person (n = 398; mean [SD], 0.00 [0.73]) vs virtual (n = 341; mean [SD], 0.07 [0.77]) SOE was not statistically significant (Welch partially overlapping-samples t test, P = .07). CONCLUSIONS: Candidate performance and examiner grading severity were comparable between the in-person and virtual SOEs, supporting the reliability and validity of the virtual oral exam in this large-volume, high-stakes setting.

Preoperative Communication Between Anesthesia, Surgery, and Primary Care Providers for Older Surgical Patients.

BACKGROUND: Suboptimal communication between clinicians remains a frequent driver of preventable adverse health care-related events, increased costs, and patient and physician dissatisfaction. METHODS: Cross-sectional surveys on preoperative interspecialty communication, tailored by stakeholder type, were administered to (1) primary care providers in northern New England, (2) anesthesia providers working in the perioperative clinic of a tertiary rural academic medical center, (3) surgeons from the same center, and (4) older surgical patients who underwent preoperative assessment at the same center. RESULTS: In total, 107/249 (43.0%) providers and 103/265 (39.9%) patients completed the survey. Preoperative communication was perceived as logistically challenging (59.8%), particularly across health systems. More than 77% of anesthesia and surgery providers indicated that they communicate frequently or sometimes, but 92.5% of primary care providers indicated that they rarely or never communicate with anesthesia providers. Some of the most common reasons for preoperative communication were discussion of complex patients, perioperative medication management, and optimization of comorbidities. Although 96.1% of older surgical patients reported that preoperative communication between providers is important, only 40.4% felt that their providers communicate very or extremely well. Many patients emphasized the importance of preoperative communication between providers to ensure transfer of critical clinical information. CONCLUSION: Surgeons and anesthesiologists infrequently communicate with primary care providers in one rural tertiary center, in contrast to patient expectations and values. These study results will help identify priorities and potentially resolvable barriers to bridging the gap between the inpatient perioperative and outpatient primary care teams. Future studies should focus on strategies to improve communication between hospital and community providers to prevent complications and readmission.

Comparing characteristics and perspectives of U.S. anesthesiology fellows in training and anesthesiologists in their first year of practice.

BACKGROUND: The purpose of this study was to evaluate relationships between demographics, professional characteristics, and perceived challenges facing the specialty of anesthesiology among physicians who entered a fellowship and those who started independent practice immediately after finishing a U.S. anesthesiology residency. METHODS: Anesthesiologists in the year after their residency graduation were invited to take an online survey during the academic years of 2016-2017, 2017-2018, and 2018-2019, with questions about their personal characteristics, the nature of their professional lives, and their perceptions of the greatest challenge facing the profession of anesthesiology. RESULTS: A total of 884 fellows-in-training and 735 anesthesiologists starting independent practice right after the completion of their residency responded. Fellows were slightly younger (mean = 33.2 vs. 34.0 years old, p < 0.001), were more likely to have a spouse who works outside the home (63.9% vs. 57.0%, p = 0.002), had fewer children (mean = 0.69 vs. 0.88, p < 0.001), worked more hours per week (mean = 56.2 vs. 52.4, p < 0.001), and were less likely to report a personal and professional life balance (66.4% vs. 72.3% positive, p = 0.005) than direct-entry anesthesiologists. Fellows and direct-entry anesthesiologists identified similar challenges in three broad themes - workforce competition (80.3% and 71.8%), healthcare system changes (30.0% and 37.9%), and personal challenges (6.4% and 8.8%). Employment security issues posed by non-physician anesthesia providers and perceived lack of appreciation of anesthesiologists' value were commonly cited. Relative weighting of challenge concerns varied between fellows and direct-entry physicians, as well as within these groups based on gender, fellowship subspecialty, location or size of practice, and frequency of supervisory roles. CONCLUSIONS: Anesthesiology fellows and direct-entry anesthesiologists had largely similar demographics and perspectives on the challenges facing anesthesiology in the United States. Group differences found in some demographics and perspectives may reflect different motivations for choosing their professional paths and their diverse professional experiences.

Association of neurocognitive disorders with morbidity and mortality in older adults undergoing major surgery in the USA: a retrospective, population-based, cohort study.

BACKGROUND: Neurocognitive disorders become increasingly common as patients age, and increasing numbers of surgical interventions are done on older patients. The aim of this study was to understand the clinical characteristics and outcomes of surgical patients with neurocognitive disorders in the USA in order to guide future targeted interventions for better care. METHODS: This retrospective cohort study used claims data for US Medicare beneficiaries aged 65 years and older with a record of inpatient admission for a major diagnostic or therapeutic surgical procedure between Jan 1, 2017, and Dec 31, 2018. Data were retrieved through a data use agreement between Dartmouth Hitchcock Medical Center and US Centers for Medicare and Medicaid Services via the Research Data Assistance Center. The exposure of interest was the presence of a pre-existing neurocognitive disorder as defined by diagnostic code within 3 years of index hospital admission. The primary outcome was mortality at 30 days, 90 days, and 365 days from date of surgery among all patients with available data. FINDINGS: Among 5 263 264 Medicare patients who underwent a major surgical procedure, 767 830 (14·59%) had a pre-existing neurocognitive disorder and 4 495 434 (85·41%) had no pre-existing neurocognitive disorder. Adjusting for demographic factors and comorbidities, patients with a neurocognitive disorder had higher 30-day (hazard ratio 1·24 [95% CI 1·23-1·25]; p<0·0001), 90-day (1·25 [1·24-1·26]; p<0·0001), and 365-day mortality (1·25 [1·25-1·26]; p<0·0001) compared with patients without a neurocognitive disorder. INTERPRETATION: Our findings suggest that the presence of a neurocognitive disorder is independently associated with an increased risk of mortality. Identification of a neurocognitive disorder before surgery can help clinicians to better disclose risks and plan for patient care after hospital discharge. FUNDING: Department of Anesthesiology and Perioperative Medicine at Dartmouth Hitchcock Medical Center.

Comparison of the frailty index and frailty phenotype and their associations with postoperative delirium incidence and severity.

BACKGROUND: Recent studies have reported an association between presurgical frailty and postoperative delirium. However, it remains unclear whether the frailty-delirium relationship differs by measurement tool (e.g., frailty index vs. frailty phenotype) and whether frailty is associated with delirium, independent of preoperative cognition. METHODS: We used the successful aging after elective surgery (SAGES) study, a prospective cohort of older adults age ≥70 undergoing major non-cardiac surgery (N = 505). Preoperative measurement of the modified mini-mental (3MS) test, frailty index and frailty phenotype were obtained. The confusion assessment method (CAM), supplemented by chart review, identified postoperative delirium. Delirium feature severity was measured by the sum of CAM-severity (CAM-S) scores. Generalized linear models were used to determine the relative risk of each frailty measure with delirium incidence and severity. Subsequent models adjusted for age, sex, surgery type, Charlson comorbidity index, and 3MS. RESULTS: On average, patients were 76.7 years old (standard deviation 5.22), 58.8% of women. For the frailty index, the incidence of delirium was 14% in robust, 17% in prefrail, and 31% in frail patients (p < 0.001). For the frailty phenotype, delirium incidence was 13% in robust, 21% in prefrail, and 27% in frail patients (p = 0.016). Frailty index, but not phenotype, was independently associated with delirium after adjustment for comorbidities (relative risk [RR] 2.13, 95% confidence interval [CI] 1.23-3.70; RR 1.61, 95% CI 0.77-3.37, respectively). Both frailty measures were associated with delirium feature severity. After adjustment for preoperative cognition, only the frailty index was associated with delirium incidence; neither index nor phenotype was associated with delirium feature severity. CONCLUSION: Both the frailty index and phenotype were associated with the development of postoperative delirium. The index showed stronger associations that remained significant after adjusting for baseline comorbidities and preoperative cognition. Measuring frailty prior to surgery can assist in identifying patients at risk for postoperative delirium.

A comparison of the American Board of Anesthesiology's in-person and virtual objective structured clinical examinations.

BACKGROUND: The American Board of Anesthesiology's Objective Structured Clinical Examination (OSCE), as a component of its initial certification process, had been administered in-person in a dedicated assessment center since its launch in 2018 until March 2020. Due to the COVID-19 pandemic, a virtual format of the exam was piloted in December 2020 and was administered in 2021. This study aimed to compare candidate performance, examiner grading severity, and scenario difficulty between these two formats of the OSCE. METHODS: The Many-Facet Rasch Model was utilized to estimate candidate performance, examiner grading severity, and scenario difficulty for the in-person and virtual OSCEs separately. The virtual OSCE was equated to the in-person OSCE by common examiners and common scenarios. Independent-samples t-test was used to compare candidate performance, and partially overlapping samples t-tests were applied to compare examiner grading severity and scenario difficulty between the in-person and virtual OSCEs. RESULTS: The in-person (n = 3235) and virtual (n = 2934) first-time candidates were comparable in age, sex, race/ethnicity, and whether U.S. medical school graduates. The virtual scenarios (n = 35, mean [0.21] ± SD [0.38] in logits) were more difficult than the in-person scenarios (n = 93, 0.00 ± 0.69, Welch's partially overlapping samples t-test, p = 0.01); there were no statistically significant differences in examiner severity (n = 390, -0.01 ± 0.82 vs. n = 304, -0.02 ± 0.93, Welch's partially overlapping samples t-test, p = 0.81) or candidate performance (2.19 ± 0.93 vs. 2.18 ± 0.92, Welch's independent samples t-test, p = 0.83) between the in-person and virtual OSCEs. CONCLUSIONS: Our retrospective analyses of first-time OSCEs found comparable candidate performance and examiner grading severity between the in-person and virtual formats, despite the virtual scenarios being more difficult than the in-person scenarios. These results provided assurance that the virtual OSCE functioned reasonably well in a high-stakes setting.

Pro-Con Debate: Judicious Benzodiazepine Administration for Preoperative Anxiolysis in Older Patients.

In this Pro-Con commentary article, we discuss the risks and benefits of administering preoperative benzodiazepines to older patients to decrease preoperative anxiety. The Pro side first focuses on the critical importance of treating preoperative anxiety and that benzodiazepines are the best tool to achieve that goal. The competing argument presented by the Con side is that myriad options exist to treat preoperative anxiety without simultaneously increasing the risk for devastating complications such as postoperative delirium. Both sides call for more high-quality investigations to determine the most effective strategies for decreasing preoperative anxiety in older adults while improving outcomes and reducing morbidity.

Update on Perioperative Delirium.

A strong association between frailty and in-hospital delirium in nonsurgical patients has been shown. Physical and cognitive frailties have been associated with decline and dysfunction in the frontal cognitive domains. Risk factors for frailty are similar to risk factors for postoperative delirium (POD). Frailty can be screened and diagnosed by various tools and instruments. Different anesthetic techniques have been studied to decrease the incidence of POD. However, no anesthetic technique has been conclusively proven to decrease the risk of POD. Patients with dementia develop delirium more often, and delirium is associated with accelerated cognitive decline.

Career decisions, training priorities, and perceived challenges for anesthesiology residents in the United States.

STUDY OBJECTIVE: This study sought to understand the timing and important factors identified by residents regarding their decision to pursue a career in anesthesiology, training areas deemed important to their future success, perceived greatest challenges facing the profession of anesthesiology, and their post-residency plans. DESIGN: The American Board of Anesthesiology administered voluntary, anonymous, repeated cross-sectional surveys to residents who began clinical anesthesia training in the U.S. from 2013 to 2016 and were subsequently followed up yearly until the completion of their residency. The analyses included data from 12 surveys (4 cohorts from clinical anesthesia years 1 to 3), including multiple-choice questions, rankings, Likert scales, and free text responses. Free responses were analyzed using an iterative inductive coding process to determine the main themes. MAIN RESULTS: The overall response rate was 36% (6480 responses to 17,793 invitations). Forty-five percent of residents chose anesthesiology during the 3rd year of medical school. "Nature of the clinical practice of anesthesiology" was the most important factor influencing their decision (average ranking of 5.93 out of 8 factors, 1 [least important] to 8 [most important]), followed by "ability to use pharmacology to acutely manipulate physiology" (5.75) and "favorable lifestyle" (5.22). "Practice management" and "political advocacy for anesthesiologists" (average rating 4.46 and 4.42, respectively, on a scale of 1 [very unimportant] to 5 [very important]) were considered the most important non-traditional training areas, followed by "anesthesiologists as leaders of the perioperative surgical home" (4.32), "structure and financing of the healthcare system" (4.27), and "principles of quality improvement" (4.26). Three out of 5 residents desired to pursue a fellowship; pain medicine, pediatric anesthesiology, and cardiac anesthesiology were the most popular choices, each accounting for approximately 20% of prospective fellows. Perceived greatest challenges facing the profession of anesthesiology included workforce competition from non-physician anesthesia providers and lack of advocacy for anesthesiologist values (referenced by 96% of respondents), changes and uncertainty in healthcare systems (30%), and personal challenges such as psychological well-being (3%). CONCLUSIONS: Most residents identified anesthesiology as their career choice during medical school. Interest in non-traditional subjects and fellowship training was common. Competition from non-physician providers, healthcare system changes, and compromised psychological well-being were perceived concerns.

Perioperative Brain Health in the Older Adult: A Patient Safety Imperative.

While people 65 years of age and older represent 16% of the population in the United States, they account for >40% of surgical procedures performed each year. Maintaining brain health after anesthesia and surgery is not only important to our patients, but it is also an increasingly important patient safety imperative for the specialty of anesthesiology. Aging is a complex process that diminishes the reserve of every organ system and often results in a patient who is vulnerable to the stress of surgery. The brain is no exception, and many older patients present with preoperative cognitive impairment that is undiagnosed. As we age, a number of changes occur in the human brain, resulting in a patient who is less resilient to perioperative stress, making older adults more susceptible to the phenotypic expression of perioperative neurocognitive disorders. This review summarizes the current scientific and clinical understanding of perioperative neurocognitive disorders and recommends patient-centered, age-focused interventions that can better mitigate risk, prevent harm, and improve outcomes for our patients. Finally, it discusses the emerging topic of sleep and cognitive health and other future frontiers of scientific inquiry that might inform clinical best practices.

Cognitive Recovery by Decade in Healthy 40- to 80-Year-Old Volunteers After Anesthesia Without Surgery.

BACKGROUND: Postoperative delirium and postoperative cognitive dysfunction are the most common complications for older surgical patients. General anesthesia may contribute to the development of these conditions, but there are little data on the association of age with cognitive recovery from anesthesia in the absence of surgery or underlying medical condition. METHODS: We performed a single-center cohort study of healthy adult volunteers 40 to 80 years old (N = 71, mean age 58.5 years, and 44% women) with no underlying cognitive dysfunction. Volunteers underwent cognitive testing before and at multiple time points after 2 hours of general anesthesia consisting of propofol induction and sevoflurane maintenance, akin to a general anesthetic for a surgical procedure, although no procedure was performed. The primary outcome was time to recovery to cognitive baseline on the Postoperative Quality of Recovery Scale (PQRS) within 30 days of anesthesia. Secondary cognitive outcomes were time to recovery on in-depth neuropsychological batteries, including the National Institutes of Health Toolbox and well-validated paper-and-pencil tests. The primary hypothesis is that time to recovery of cognitive function after general anesthesia increases across decades from 40 to 80 years of age. We examined this with discrete-time logit regression (for the primary outcome) and linear mixed models for interactions of age decade with time postanesthesia (for secondary outcomes). RESULTS: There was no association between age group and recovery to baseline on the PQRS; 36 of 69 (52%) recovered within 60-minute postanesthesia and 63 of 69 (91%) by day 1. Hazard ratios (95% confidence interval) for each decade compared to 40- to 49-year olds were: 50 to 59 years, 1.41 (0.50-4.03); 60 to 69 years, 1.03 (0.35-3.00); and 70 to 80 years, 0.69 (0.25-1.88). There were no significant differences between older decades relative to the 40- to 49-year reference decade in recovery to baseline on secondary cognitive measures. CONCLUSIONS: Recovery of cognitive function to baseline was rapid and did not differ between age decades of participants, although the number in each decade was small. These results suggest that anesthesia alone may not be associated with cognitive recovery in healthy adults of any age decade.

A Processed Electroencephalogram-Based Brain Anesthetic Resistance Index Is Associated With Postoperative Delirium in Older Adults: A Dual Center Study.

BACKGROUND: Some older adults show exaggerated responses to drugs that act on the brain. The brain's response to anesthetic drugs is often measured clinically by processed electroencephalogram (EEG) indices. Thus, we developed a processed EEG-based measure of the brain's resistance to volatile anesthetics and hypothesized that low scores on it would be associated with postoperative delirium risk. METHODS: We defined the Duke Anesthesia Resistance Scale (DARS) as the average bispectral index (BIS) divided by the quantity (2.5 minus the average age-adjusted end-tidal minimum alveolar concentration [aaMAC] inhaled anesthetic fraction). The relationship between DARS and postoperative delirium was analyzed in 139 older surgical patients (age ≥65) from Duke University Medical Center (n = 69) and Mt Sinai Medical Center (n = 70). Delirium was assessed by geriatrician interview at Duke, and by research staff utilizing the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) instrument at Mt Sinai. We examined the relationship between DARS and delirium and used the Youden index to identify an optimal low DARS threshold (for delirium risk), and its associated 95% bootstrap confidence bounds. We used multivariable logistic regression to examine the relationship between low DARS and delirium risk. RESULTS: The relationship between DARS and delirium risk was nonlinear, with higher delirium risk at low DARS scores. A DARS threshold of 28.755 maximized the Youden index for the association between low DARS and delirium, with bootstrap 95% confidence bounds of 26.18 and 29.80. A low DARS (<28.755) was associated with increased delirium risk in multivariable models adjusting for site (odds ratio [OR] [95% confidence interval {CI}] = 4.30 [1.89-10.01]; P = .001), or site-plus-patient risk factors (OR [95% CI] = 3.79 [1.63-9.10]; P = .003). These associations with postoperative delirium risk remained significant when using the 95% bootstrap confidence bounds for the low DARS threshold (P < .05 for all). Further, a low DARS (<28.755) was associated with delirium risk after accounting for opioid, midazolam, propofol, phenylephrine, and ketamine dosage as well as site (OR [95% CI] = 4.21 [1.80-10.16]; P = .002). This association between low DARS and postoperative delirium risk after controlling for these other medications remained significant (P < .05) when using either the lower or the upper 95% bootstrap confidence bounds for the low DARS threshold. CONCLUSIONS: These results demonstrate that an intraoperative processed EEG-based measure of lower brain anesthetic resistance (ie, low DARS) is independently associated with increased postoperative delirium risk in older surgical patients.

Lateralisation of subcortical functional connectivity during and after general anaesthesia.

BACKGROUND: Arousal and awareness are two important components of consciousness states. Functional neuroimaging has furthered our understanding of cortical and thalamocortical mechanisms of awareness. Investigating the relationship between subcortical functional connectivity and arousal has been challenging owing to the relatively small size of brainstem structures and thalamic nuclei, and their depth in the brain. METHODS: Resting state functional MRI scans of 72 healthy volunteers were acquired before, during, 1 h after, and 1 day after sevoflurane general anaesthesia. Functional connectivity of subcortical regions of interest vs whole brain and homotopic functional connectivity for assessment of left-right symmetry analyses of both cortical and subcortical regions of interest were performed. Both analyses used high resolution atlases generated from deep brain stimulation applications. RESULTS: Functional connectivity in subcortical loci within the thalamus and of the ascending reticular activating system was sharply restricted under anaesthesia, featuring a general lateralisation of connectivity. Similarly, left-right homology was sharply reduced under anaesthesia. Subcortical bilateral functional connectivity was not fully restored after emergence from anaesthesia, although greater restoration was seen between ascending reticular activating system loci and specific thalamic nuclei thought to be involved in promoting and maintaining arousal. Functional connectivity was fully restored to baseline by the following day. CONCLUSIONS: Functional connectivity in the subcortex is sharply restricted and lateralised under general anaesthesia. This restriction may play a part in loss and return of consciousness. CLINICAL TRIAL REGISTRATION: NCT02275026.

Processed intraoperative burst suppression and postoperative cognitive dysfunction in a cohort of older noncardiac surgery patients.

Postoperative cognitive dysfunction (POCD) is a decline in cognitive test performance which persists months after surgery. There has been great interest in the anesthesia community regarding whether variables generated by commercially available processed EEG monitors originally marketed to prevent awareness under anesthesia can be used to guide intraoperative anesthetic management to prevent POCD. Processed EEG monitors represent an opportunity for anesthesiologists to directly monitor the brain even if they have not been trained to interpret EEG waveforms. There is continued equipoise regarding whether any of the variables generated by the machines' interpretation of raw data are associated with POCD. Most literature has focused on the depth of anesthesia number, however recent studies have shown that processed depth may not be accurate in older age groups due to reduced alpha band power. Burst suppression is an encephalographic pattern of high voltage activity alternating with periods of electrical silence and is another marker of depth which can be obtained from commercial processed EEG monitors. We performed a prospective cohort study to determine whether burst suppression and burst suppression ratio as measured by the BIS Monitor (Bispectral Index, BIS Medtronic, Boulder CO), is associated with cognitive dysfunction 3 months after surgery. We recruited 167 elective surgery patients, 65 years of age and older, anticipated to require at least 2 day inpatient admission. Our main outcome measure was cognitive decline in composite z-score on the Alzheimer's Disease Research Center UDS Battery of at least 1 standard deviation 3 months after surgery relative to preoperative baseline. 14% experienced POCD, this group was older (72 [70, 74] versus 70 [67, 75] years), and had frailty scores as measured by the FRAIL Scale (2 [0, 3] versus 1 [0, 2]) and lower baseline z-scores (- 0.2 [- 0.6, 0.5] versus 0.1 [- 0.3, 0.5]). There was a univariable association between suppression ratio > 10 (SR > 10) and POCD (4.8 [0, 37.3] versus 15.4 [4.0-142.4] min), p = .038. However, after adjustment this relationship did not persist, only anesthetic technique, age, and pain remained in the model. In our cohort of older elective noncardiac surgery patients we found a marginal association between processed burst suppression (total burst suppression p = .067, SR > 5 p = .052, SR > 10.038) which did not persist in a multivariable model. Patients with POCD had almost twice the number of minutes of burst suppression, and three times the amount of time for SR > 5 and > 10. Our finding may be a limitation of the monitor's ability to detect burst suppression. The consistent trend towards more intraoperative burst suppression in patients who developed POCD suggests that future studies are needed to investigate the relationship of raw intraoperative burst suppression and POCD.Trial registry Clinical trial number and registry URL: Optimizing Postoperative Cognitive Dysfunction in the Elderly-PRESERVE, Clinical Trials Gov# NCT02650687; https://clinicaltrials.gov/ct2/show/NCT02650687 .

Palliative Care Consultation for Hospitalized Patients with Primary and Secondary Brain Tumors at a Single Academic Center.

Introduction: Studies addressing palliative care delivery in neuro-oncology are limited. Objectives: To compare inpatients with brain tumors who received palliative care (through referral or trigger) with those receiving usual care. Design: Retrospective cohort study. Setting/Subjects: Inpatients with primary or secondary brain tumors who did or did not receive palliative care at a U.S. medical center. Measurements: Sociodemographic, clinical, and utilization characteristics were compared. Results: Of 1669 brain tumor patients, 386 (23.1%) received palliative care [nontrigger: 246 (14.7%); trigger: 140 (8.4%)] and 1283 (76.9%) received usual care. Nontrigger patients were oldest (mean age 65.0 years; trigger: 61.1 years; usual care: 55.5 years; p < 0.001); sickest at baseline (mean Elixhauser comorbidity index 3.76; trigger: 3.49; usual care: 1.84; p < 0.001); and had highest in-hospital death [34 (13.8%), trigger: 10 (7.1%), usual care: 7 (0.5%); p < 0.001] and hospice discharge [54 (22.0%), trigger: 18 (12.9%), usual care: 14 (1.1%); p < 0.001]. Conclusions: Trigger criteria may promote earlier palliative care referral, yet criteria tailored for neuro-oncology are undeveloped.