Pre-operative mild cognitive dysfunction predicts risk for post-operative delirium after elective cardiac surgery

Postoperative Outcomes in Elderly Patients Undergoing Cardiac Surgery With Preoperative Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Older patients with preoperative cognitive impairment are at risk for increased postoperative complications after noncardiac surgery. This systematic review and meta-analysis aimed to determine the association between preoperative cognitive impairment and dementia and postoperative outcomes in older surgical patients after cardiac surgery.

METHODS

Eight electronic databases were searched from inception to January 4, 2022. Inclusion criteria were cardiac surgery patients ≥60 years of age; preoperative cognitive impairment; ≥1 postoperative complication reported; comparator group with no preoperative cognitive impairment; and written in English. Using a random-effects model, we calculated effect sizes as odds ratio (OR) and standardized mean differences (SMDs). Risk of random error was assessed by applying trial sequential analysis.

RESULTS

Sixteen studies (62,179 patients) were included. Preoperative cognitive impairment was associated with increased risk of delirium in older patients after cardiac surgery (70.0% vs 20.5%; OR, 8.35; 95% confidence interval [CI], 4.25-16.38; I2, 0%; P < .00001). Cognitive impairment was associated with increased hospital length of stay (LOS; SMD, 0.36; 95% CI, 0.20-0.51; I2, 22%; P < .00001) and intensive care unit (ICU) LOS (SMD, 0.39; 95% CI, 0.09-0.68; I2, 70%; P = .01). No significant association was seen for 30-day mortality (1.7% vs 1.1%; OR, 2.58; 95% CI, 0.64-10.44; I2, 55%; P = .18).

CONCLUSIONS

In older patients undergoing cardiac surgery, cognitive impairment was associated with an 8-fold increased risk of delirium, a 5% increase in absolute risk of major postoperative bleeding, and an increase in hospital and ICU LOS by approximately 0.4 days. Further research on the feasibility of implementing routine neurocognitive testing is warranted.

Predisposing and Precipitating Factors Associated With Delirium: A Systematic Review

IMPORTANCE

Despite discrete etiologies leading to delirium, it is treated as a common end point in hospital and in clinical trials, and delirium research may be hampered by the attempt to treat all instances of delirium similarly, leaving delirium management as an unmet need. An individualized approach based on unique patterns of delirium pathophysiology, as reflected in predisposing factors and precipitants, may be necessary, but there exists no accepted method of grouping delirium into distinct etiologic subgroups.

OBJECTIVE

To conduct a systematic review to identify potential predisposing and precipitating factors associated with delirium in adult patients agnostic to setting.

EVIDENCE REVIEW

A literature search was performed of PubMed, Embase, Web of Science, and PsycINFO from database inception to December 2021 using search Medical Subject Headings (MeSH) terms consciousness disorders, confusion, causality, and disease susceptibility, with constraints of cohort or case-control studies. Two reviewers selected studies that met the following criteria for inclusion: published in English, prospective cohort or case-control study, at least 50 participants, delirium assessment in person by a physician or trained research personnel using a reference standard, and results including a multivariable model to identify independent factors associated with delirium.

FINDINGS

A total of 315 studies were included with a mean (SD) Newcastle-Ottawa Scale score of 8.3 (0.8) out of 9. Across 101 144 patients (50 006 [50.0%] male and 49 766 [49.1%] female patients) represented (24 015 with delirium), studies reported 33 predisposing and 112 precipitating factors associated with delirium. There was a diversity of factors associated with delirium, with substantial physiological heterogeneity.

CONCLUSIONS AND RELEVANCE

In this systematic review, a comprehensive list of potential predisposing and precipitating factors associated with delirium was found across all clinical settings. These findings may be used to inform more precise study of delirium's heterogeneous pathophysiology and treatment.

Outcomes of postoperative delirium in patients undergoing cardiac surgery: A systematic review and meta-analysis

Background

Postoperative delirium (POD) is an acute brain dysfunction that is frequently observed in patients undergoing cardiac surgery. Increasing evidence indicates POD is related to higher mortality among cardiac surgical patients, but the results remain controversial. Moreover, a quantitative evaluation of the influence of POD on hospital days, intensive care unit (ICU) time, and mechanical ventilation (MV) time has not been performed.

Objective

This study aimed to evaluate the correlation between POD and outcomes in patients undergoing cardiac surgery by a systematic review and meta-analysis.

Materials and methods

A total of 7 electronic databases (Cochrane Library, PubMed, EMBASE, CINAHL Complete, MEDLINE, Wan-fang database, and China National Knowledge Infrastructure) were searched from January 1980 to July 20, 2021, with language restrictions to English and Chinese, to estimate the impact of the POD on outcome in patients who underwent cardiac surgery. The meta-analysis was registered with PROSPERO (Registration: CRD42021228767).

Results

Forty-two eligible studies with 19785 patients were identified. 3368 (17.0%) patients were in the delirium group and 16417 (83%) were in the non-delirium group. The meta-analysis showed that compared to patients without POD, patients with POD had 2.77-fold higher mortality (OR = 2.77, 95% CI 1.86-4.11, P < 0.001), 5.70-fold higher MV (>24h) rate (OR = 5.70, 95% CI 2.93-11.09, P < 0.001); and longer MV time (SMD = 0.83, 95% CI 0.57-1.09, P < 0.001), ICU time (SMD = 0.91, 95% CI 0.60-1.22, P < 0.001), hospital days (SMD = 0.62, 95% CI 0.48-0.76, P < 0.001).

Conclusion

The synthesized evidence suggests that POD is causally related to the increased risk of mortality, prolonged length of ICU and hospital stay, and a longer duration of MV time. Future research should focus on the interventions for POD, to reduce the incidence.

Systematic review registration

[www.crd.york.ac.uk/PROSPERO], identifier [CRD42021228767].

Prediction of Postoperative Delirium After Cardiac Surgery with A Quick Test of Cognitive Speed, Mini-Mental State Examination and Hospital Anxiety and Depression Scale

Purpose

To evaluate if preoperative assessment with A Quick Test of Cognitive Speed (AQT) could increase the accuracy of predicting delirium after cardiac surgery compared to Mini-Mental State Examination (MMSE), and examine if a composite of variables, including cognitive function and depressive symptoms, could be useful to predict delirium.

Patients and Methods

Cardiac surgery was performed in 218 patients (mean age 72 years). Preoperative evaluation involved AQT, MMSE and Hospital Anxiety And Depression Scale (HADS). Postoperative delirium was assessed using Nursing Delirium Screening Scale (Nu-DESC) and Confusion Assessment Method-ICU (CAM-ICU). Logistic regression was performed to detect predictors of postoperative delirium and receiver operator characteristic curves (ROC) with area under the curve (AUC) to determine the accuracy.

Results

Postoperative delirium occurred in 47 patients (22%) who had lower MMSE scores (median (range), 27 (19–30) vs 28 (20–30), p=0.009) and slower AQT (median (range), 76 (48–181) vs 70 (40–182) seconds, p=0.030) than patients without delirium. Predictive power measured as AUC (95% CI) was 0.605 (0.51–0.70) for AQT and 0.623 (0.53–0.72) for MMSE. Logistic regression (OR, 95% CI) showed MMSE <27 points (2.72, 1.27–5.86), AQT >70 sec (2.26, 1.03–4.95), HADS-D >4 points (2.60, 1.21–5.58) and longer cardiopulmonary bypass-time (1.007, 1.002–1.013) to be associated with postoperative delirium. Combining these parameters yielded an AUC of 0.736 (0.65–0.82).

Conclusion

The ability of predicting delirium using AQT was similar to MMSE, and only slightly higher by combining AQT and MMSE. Adding HADS-D and cardiopulmonary bypass-time to MMSE and AQT increased the predictive power to a borderline acceptable discriminatory value. Preoperative cognitive tests and screening for depressive symptoms may help identify patients at risk of postoperative delirium. Yet, there is still a need to establish useful preoperative tests.

Gender Differences and Postoperative Delirium in Adult Patients Undergoing Cardiac Valve Surgery

Background: Postoperative delirium (POD) is common in patients following cardiac surgery. According to studies on non-cardiac surgery, males suffered from higher incidence of POD. However, there is no report about effect of gender differences on POD occurrence in cardiac surgery patients. The aim of this study was to investigate the effect of gender differences on POD occurrence in adult patients after cardiac valve surgery.

Methods: This is a retrospective case-control study. We recorded the clinical data in adult patients who underwent elective cardiac valve surgery from May 2019 to October 2020. POD was assessed by the Confusion Assessment Method for Intensive Care Unit. Univariate analysis was used to screen the potential risk factors. Collinearity analysis was conducted to detect overlapping predictor variables on the outcomes. A multivariate logistic regression with odds ratio (OR) and 95% confidence interval (CI) was used to identify the independent risk factors. The Hosmer-Lemeshow test was performed to show the good calibration of the logistic regression model.

Results: In total, we recorded the perioperative data in 431 adult patients, including 212 males and 219 females. Sixty patients suffered from POD, including 39 males and 21 females. Twenty-one perioperative variables were selected, and 11 were screened by univariate analysis. We did not detect the severe collinearity among the 11 variables. Male gender was identified as a significant risk factor in POD occurrence in patients undergoing cardiac surgery (Adjusted OR: 2.213, 95% CI: 1.049–4.670, P = 0.037). The Hosmer-Lemeshow test demonstrated good calibration of the logistic regression model (χ² = 7.238, P = 0.511). Besides, compared with females, the relationship of male and delirium subtypes was as follows: (1) hyperactive: adjusted OR: 3.384, 95% CI: 1.335–8.580, P = 0.010; (2) hypoactive: adjusted OR: 0.509, 95% CI: 0.147–1.766, P = 0.287. A Stratification analysis by age demonstrated that the males showed higher POD incidence in patients aged younger than 60 years (adjusted OR: 4.384, 95% CI: 1.318–14.586, P = 0.016).

Conclusions: Male gender is an important risk factor in POD occurrence in patients following cardiac surgery. Furthermore, the incidence of hyperactive delirium is higher in males. Besides, the male patients aged younger than 60 years are at high risk of POD. We should pay more attention to the male patients to prevent their POD occurrence.

Postoperative delirium after cardiac surgery of elderly patients as an independent risk factor for prolonged length of stay in intensive care unit and in hospital

Background

Postoperative delirium (POD) is a relevant and underdiagnosed complication after cardiac surgery that is associated with increased intensive care unit (ICU) and hospital length of stay (LOS). The aim of this subgroup study was to compare the frequency of tested POD versus the coded International Statistical Classification of Diseases and Related Health Problems (ICD) diagnosis of POD and to evaluate the influence of POD on LOS in ICU and hospital.

Methods

254 elective cardiac surgery patients (mean age, 70.5 ± 6.4 years) at the University Hospital Bonn between September 2018 and October 2019 were evaluated. The endpoint tested POD was considered positive, if one of the tests Confusion Assessment Method for ICU (CAM-ICU) or Confusion Assessment Method (CAM), 4 'A's Test (4AT) or Delirium Observation Scale (DOS) was positive on one day.

Results

POD occurred in 127 patients (50.0%). LOS in ICU and hospital were significantly different based on presence (ICU 165.0 ± 362.7 h; Hospital 26.5 ± 26.1 days) or absence (ICU 64.5 ± 79.4 h; Hospital 14.6 ± 6.7 days) of POD (p < 0.001). The multiple linear regression showed POD as an independent predictor for a prolonged LOS in ICU (48%; 95%CI 31–67%) and in hospital (64%; 95%CI 27–110%) (p < 0.001). The frequency of POD in the study participants that was coded with the ICD F05.0 and F05.8 by hospital staff was considerably lower than tests revealed by the study personnel.

Conclusion

Approximately 50% of elderly patients who underwent cardiac surgery developed POD, which is associated with an increased ICU and hospital LOS. Furthermore, POD is highly underdiagnosed in clinical routine.

Physical Performance and Risk of Postoperative Delirium in Older Adults Undergoing Aortic Valve Replacement

Background

Delirium is a major risk factor for poor recovery after surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). It is unclear whether preoperative physical performance tests improve delirium prediction.

Objective

To examine whether physical performance tests can predict delirium after SAVR and TAVR, and adapt an existing delirium prediction rule for cardiac surgery, which includes Mini-Mental State Examination (MMSE), depression, prior stroke, and albumin level.

Design

Prospective cohort, 2014-2017.

Setting

Single academic center.

Subjects

A total of 187 patients undergoing SAVR (n=77) or TAVR (n=110).

Methods

The Short Physical Performance Battery (SPPB) score was calculated based on gait speed, balance, and chair stands (range: 0-12 points, lower scores indicate poor performance). Delirium was assessed using the Confusion Assessment Method. We fitted logistic regression to predict delirium using SPPB components and risk factors of delirium.

Results

Delirium occurred in 35.8% (50.7% in SAVR and 25.5% in TAVR). The risk of delirium increased for lower SPPB scores: 10-12 (28.2%), 7-9 (34.5%), 4-6 (37.5%) and 0-3 (44.1%) (p-for-trend=0.001). A model that included gait speed <0.46 meter/second (OR, 2.7; 95% CI, 1.2-6.4), chair stands time ≥11.2 seconds (OR, 3.5; 95% CI, 1.0-12.4), MMSE <24 points (OR, 2.9; 95% CI, 1.3-6.4), isolated SAVR (OR, 5.4; 95% CI, 2.1-13.8), and SAVR and coronary artery bypass grafting (OR, 15.8; 95% CI, 5.5-45.7) predicted delirium better than the existing prediction rule (C statistics: 0.71 vs 0.61; p=0.035).

Conclusion

Assessing physical performance, in addition to cognitive function, can help identify high-risk patients for delirium after SAVR and TAVR.

Comprehensive Geriatric Assessment in the Management of Older Patients With Cardiovascular Disease

Cardiovascular disease (CVD) disproportionately affects older adults. It is expected that by 2030, one in five people in the United States will be older than 65 years. Individuals with CVD now live longer due, in part, to current prevention and treatment approaches. Addressing the needs of older individuals requires inclusion and assessment of frailty, multimorbidity, depression, quality of life, and cognition. Despite the conceptual relevance and prognostic importance of these factors, they are seldom formally evaluated in clinical practice. Further, although these constructs coexist with traditional cardiovascular risk factors, their exact prevalence and prognostic impact remain largely unknown. Development of the right decision tools, which include these variables, can facilitate patient-centered care for older adults. These gaps in knowledge hinder optimal care use and underscore the need to rigorously evaluate the optimal constructs for providing care to older adults. In this review, we describe available tools to examine the prognostic role of age-related factors in patients with CVD.

Effects of an abnormal mini-mental state examination score on postoperative outcomes in geriatric surgical patients: a meta-analysis

Background

Perioperative cognitive impairment (CI) following surgeries is prevalent in geriatric surgical population aged 60 and older. This meta-analysis was designed to investigate whether the Mini-Mental State Examination (MMSE) has prognostic value on adverse outcomes in aged surgical patients.

Methods

PubMed, Cochrane, Embase and Medline through the Ovid were searched. Meta-analyses were carried out for CI versus non-cognitive impairment (NCI). Quality of evidence was assessed by the GRADE approach.

Results

One randomized controlled trial, two retrospective cohort trials, and 18 prospective cohort trials were included in the meta-analysis. Perioperative diagnosis of CI by the MMSE had higher rates of patients suffering from postoperative delirium (POD) [odd ratio (OR) 5.02, 95% confidence interval (CI) 3.27, 7.71, P < 0.00001], in-hospital mortality (OR 7.51, 95% CI 2.17, 26.02, P = 0.001), mortality within 1 year (OR 2.53, 95% CI 1.95,3.29, P < 0.00001). Postoperative CI patients had no extended length of stay in orthopedic [standardized mean difference (SMD) -0.10, 95% CI -0.20, 0.17, P = 0.91)] nor rehabilitation wards ((SMD, 0.04; 95% CI, − 0.23 to 0.31; P = 0.78).

Conclusion

Older patients with perioperative CI were more likely to suffer from POD and mortality. The MMSE showed certain value on risk stratification and prognosis evaluation in geriatric surgical population.

Trial registration

PROSPERO CRD42018108739.

Electronic supplementary material

The online version of this article (10.1186/s12871-019-0735-5) contains supplementary material, which is available to authorized users.

Protocol for a prospective cohort study of assessing postoperative cognitive changes after total hip and knee arthroplasty in the Greater Toronto area

INTRODUCTION

Cognitive changes after anaesthesia and surgery, such as delirium and postoperative cognitive dysfunction (POCD), are common and lead to poor outcomes and increased healthcare costs. While several interventions for delirium exist, there are no effective treatment strategies for POCD. Understanding the risks and contributing factors may offer clinicians unique opportunities to better identify and develop preventative interventions for those at higher risk. Elderly patients undergoing orthopaedic surgery are at high risk of developing postoperative delirium (PD) and POCD. The incidence of POCD has not been rigorously studied in the total hip and knee arthroplasty (THA/TKA) population. Therefore, we have designed a prospective, observational cohort study to assess POCD in patients undergoing THA/TKA, both increasingly common procedures. The incidence of PD and POCD in a high volume, tertiary care arthroplasty centre will be determined and associated risk factors will be identified.

METHODS AND ANALYSIS

Cognitive function will be tested with a computer-based cognitive assessment tool [CogState Brief Battery], preoperatively at baseline and postoperatively while in hospital at (<3 days), 6 weeks and 4.5 months. The primary outcome is the incidence of postoperative cognitive decline at 4.5 months. Logistic regression analysis is planned to test the association of POCD with several potential risk factors. In addition, delirium will be assessed preoperatively and postoperatively in the hospital using the Confusion Assessment Method (3D-CAM).

ETHICS AND DISSEMINATION

The protocol for this prospective observational study was approved by the Sunnybrook Health Sciences Centre Research Ethics Board (REB#: 040-2017). Recruitment commenced in May 2017 and will continue until 2019. The results will be disseminated in a peer-reviewed journal and in scientific meetings.

TRIAL REGISTRATION NUMBER

NCT03147937.

Trajectory of severity of postoperative delirium symptoms and its prospective association with cognitive function in patients with gastric cancer: results from a prospective observational study

PURPOSE

Delirium is a common neurocognitive complication in cancer. Despite this, the studies examining the trajectory of the severity of delirium symptoms and its impact on health outcome in gastric cancer is rather limited. This study examined the trajectory of delirium symptom severity (DSS) following resection surgery for gastric cancer and its prospective association with cognitive function.

METHODS

A three-wave prospective observational study was conducted with 242 gastric cancer patients admitted for resection surgery at a teaching hospital in South Korea from May 2016 to November 2017. DSS was assessed by the clinical staff before and 1, 2, 3, and 7 days after surgery using the Delirium Rating Scale-Revised-98. A survey including the Functional Assessment of Cancer Therapy-Cognitive Scale (FACT-Cog) and Mini-Mental State Examination (MMSE) was administered before surgery (T0), 7 days after (T1), and 3 to 6 months after surgery (T2).

RESULTS

Out of 242 participants, 48.8% (118) completed the survey at all three time points, 43.4% (105) did so for two time points, and 7.9% (19) for one time point. No cases of full delirium were observed over four postoperative time points. Latent growth curve modeling analyses indicated that DSS declined over 3 days after surgery. Age and anesthesia time were positively associated with the initial level of DSS. A medication history for memory complaints was related to a slower recovery from delirium symptoms. While the use of propofol as an anesthetic agent was associated with lower initial DSS, it predicted a slower recovery from DSS. A higher initial DSS predicted a lower T1 MMSE score.

CONCLUSIONS

Severity of postoperative delirium symptoms predicts a short-term and objective cognitive function post-surgery. Monitoring and timely treatment of postoperative delirium symptoms is needed to diminish cognitive consequences in gastric cancer patients.

Best Practices for Postoperative Brain Health: Recommendations From the Fifth International Perioperative Neurotoxicity Working Group

As part of the American Society of Anesthesiology Brain Health Initiative goal of improving perioperative brain health for older patients, over 30 experts met at the fifth International Perioperative Neurotoxicity Workshop in San Francisco, CA, in May 2016, to discuss best practices for optimizing perioperative brain health in older adults (ie, >65 years of age). The objective of this workshop was to discuss and develop consensus solutions to improve patient management and outcomes and to discuss what older adults should be told (and by whom) about postoperative brain health risks. Thus, the workshop was provider and patient oriented as well as solution focused rather than etiology focused. For those areas in which we determined that there were limited evidence-based recommendations, we identified knowledge gaps and the types of scientific knowledge and investigations needed to direct future best practice. Because concerns about perioperative neurocognitive injury in pediatric patients are already being addressed by the SmartTots initiative, our workshop discussion (and thus this article) focuses specifically on perioperative cognition in older adults. The 2 main perioperative cognitive disorders that have been studied to date are postoperative delirium and cognitive dysfunction. Postoperative delirium is a syndrome of fluctuating changes in attention and level of consciousness that occurs in 20%-40% of patients >60 years of age after major surgery and inpatient hospitalization. Many older surgical patients also develop postoperative cognitive deficits that typically last for weeks to months, thus referred to as postoperative cognitive dysfunction. Because of the heterogeneity of different tools and thresholds used to assess and define these disorders at varying points in time after anesthesia and surgery, a recent article has proposed a new recommended nomenclature for these perioperative neurocognitive disorders. Our discussion about this topic was organized around 4 key issues: preprocedure consent, preoperative cognitive assessment, intraoperative management, and postoperative follow-up. These 4 issues also form the structure of this document. Multiple viewpoints were presented by participants and discussed at this in-person meeting, and the overall group consensus from these discussions was then drafted by a smaller writing group (the 6 primary authors of this article) into this manuscript. Of course, further studies have appeared since the workshop, which the writing group has incorporated where appropriate. All participants from this in-person meeting then had the opportunity to review, edit, and approve this final manuscript; 1 participant did not approve the final manuscript and asked for his/her name to be removed.

Clinical outcomes in older surgical patients with mild cognitive impairment

INTRODUCTION

Older adults, including those with mild cognitive impairment (MCI), are increasingly undergoing surgery.

METHODS

Relative risks (RRs) of MCI alone or with delirium on adverse outcomes were estimated in an ongoing prospective, observational cohort study of 560 nondemented adults aged ≥70 years.

RESULTS

MCI (n = 61, 11%) was associated with increased RR of delirium (RR = 1.9, P < .001) and delirium severity (RR = 4.6, P < .001). Delirium alone (n = 107), but not MCI alone (n = 34), was associated with multiple adverse outcomes including more major postoperative complication(s) (RR = 2.5, P = .002) and longer length of stay (RR = 2.2, P < .001). Patients with concurrent MCI and delirium (n = 27) were more often discharged to a postacute facility (RR = 1.4, P < .001) and had synergistically increased risk for new impairments in cognitive functioning (RR = 3.6, P < .001).

DISCUSSION

MCI is associated with increased risk of delirium incidence and severity. Patients with delirium and MCI have synergistically elevated risk of developing new difficulties in cognitively demanding tasks.

Systematic review of prediction models for delirium in the older adult inpatient

OBJECTIVE

To identify existing prognostic delirium prediction models and evaluate their validity and statistical methodology in the older adult (≥60 years) acute hospital population.

DESIGN

Systematic review.

DATA SOURCES AND METHODS

PubMed, CINAHL, PsychINFO, SocINFO, Cochrane, Web of Science and Embase were searched from 1 January 1990 to 31 December 2016. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses and CHARMS Statement guided protocol development.

INCLUSION CRITERIA

age >60 years, inpatient, developed/validated a prognostic delirium prediction model.

EXCLUSION CRITERIA

alcohol-related delirium, sample size ≤50. The primary performance measures were calibration and discrimination statistics. Two authors independently conducted search and extracted data. The synthesis of data was done by the first author. Disagreement was resolved by the mentoring author.

RESULTS

The initial search resulted in 7,502 studies. Following full-text review of 192 studies, 33 were excluded based on age criteria (<60 years) and 27 met the defined criteria. Twenty-three delirium prediction models were identified, 14 were externally validated and 3 were internally validated. The following populations were represented: 11 medical, 3 medical/surgical and 13 surgical. The assessment of delirium was often non-systematic, resulting in varied incidence. Fourteen models were externally validated with an area under the receiver operating curve range from 0.52 to 0.94. Limitations in design, data collection methods and model metric reporting statistics were identified.

CONCLUSIONS

Delirium prediction models for older adults show variable and typically inadequate predictive capabilities. Our review highlights the need for development of robust models to predict delirium in older inpatients. We provide recommendations for the development of such models.

Risk factors and outcome of postoperative delirium after transcatheter aortic valve replacement

BACKGROUND

POD is associated with a worse postoperative course in patients after cardiac surgery, but its incidence and effects after TAVR are not well-understood. The aim of the present study was to analyze incidence, risk factors, and in-hospital outcomes of postoperative delirium (POD) after transfemoral (TF-AVR) and transapical (TA-AVR) transcatheter aortic valve replacement (TAVR) in a nationwide cohort.

METHODS AND RESULTS

Administrative data on all patients undergoing isolated TAVR in Germany in 2014 were analyzed. 9038 TF-AVR and 2522 TA-AVR procedures were performed. POD incidence was 7% after TF-AVR and 12% after TA-AVR. Atrial fibrillation (TF: OR 1.35, p < 0.001; TA: OR 1.53, p = 0.001) and NYHA III/IV (TF: OR 1.23, p = 0.017, TA: OR 1.51, p = 0.001) were independent risk factors for POD. Dementia was a risk factor only in TF-AVR (OR 3.04, p < 0.001). Female sex was protective (TF: OR 0.56, p < 0.001, TA: OR 0.51, p < 0.001). We found the occurrence of POD to be associated with more postoperative complications such as stroke and bleeding. Consequently, patients with POD were ventilated and hospitalized longer and suffered an increased risk of in-hospital mortality (unadjusted OR TF: 1.83, p = 0.001, TA: 1.82, p = 0.01). After adjusting for postoperative events and comorbidities, POD's effect on in-hospital mortality disappeared. In contrast, stroke and bleeding remained independent predictors for mortality irrespective of POD.

CONCLUSIONS

Patients with POD after TAVR are at increased risk for in-hospital mortality. However, after adjusting for postoperative events and comorbidities, stroke and bleeding, but not POD, are independent mortality predictors.

The relationship between cerebral oxygen saturation and quantitative metrics of neurological function after coronary bypass surgery: a feasibility study

BACKGROUND

It is well-known that patients undergoing coronary artery bypass grafting (CABG) surgery may experience neurological dysfunction following their operation. However, the nature of this dysfunction has not been properly quantified. Furthermore, the relationship between postoperative impairment and cerebral oxygen saturation during surgery has remained unclear. This study aims to define the feasibility of using robotic technology to quantify post-CABG neurocognitive function, and to correlate these objective metrics with intraoperative cerebral oxygenation.

METHODS

Neurological function was tested using robotic technology and a standardized questionnaire before and 3 months after surgery. In addition, frontal lobe cerebral oxygenation was recorded using the FORESIGHT near-infrared spectrometer for the duration of the operation. Pre- and postoperative neurological assessment was performed for 24 participants. Of those 24, 20 participants had cerebral oxygenation recorded during their surgery.

RESULTS

The cerebral oximeter captured 97.2% of the data. Majority of patients experienced no significant decline in overall neurocognitive function. Abnormal postoperative scores were most frequent in a sensorimotor task that involved additional cognitive load. In this reverse visually guided reaching task, postoperative scores significantly correlated with mean and minimum intraoperative cerebral oxygenation values, with lower values being associated with worse performance.

CONCLUSIONS

It is feasible to use robotic technology as a quantitative and objective neurocognitive assessment method for patients undergoing CABG. The relationship between quantitative metrics of neurocognitive function and intraoperative cerebral oxygenation warrants further investigation.

Identifying Older Adults at Risk of Delirium Following Elective Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Postoperative delirium is a common preventable complication experienced by older adults undergoing elective surgery. In this systematic review and meta-analysis, we identified prognostic factors associated with the risk of postoperative delirium among older adults undergoing elective surgery.

METHODS

Medline, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, and AgeLine were searched for articles published between inception and April 21, 2016. A total of 5692 titles and abstracts were screened in duplicate for possible inclusion. Studies using any method for diagnosing delirium were eligible. Two reviewers independently completed all data extraction and quality assessments using the Cochrane Risk-of-Bias Tool for randomized controlled trials (RCTs) and the Newcastle-Ottawa Scale (NOS) for cohort studies. Random effects meta-analysis models were used to derive pooled effect estimates.

RESULTS

Forty-one studies (9384 patients) reported delirium-related prognostic factors. Among our included studies, the pooled incidence of postoperative delirium was 18.4% (95% confidence interval [CI] 14.3-23.3%, number needed to follow [NNF] = 6). Geriatric syndromes were important predictors of delirium, namely history of delirium (odds ratio [OR] 6.4, 95% CI 2.2-17.9), frailty (OR 4.1, 95% CI 1.4-11.7), cognitive impairment (OR 2.7, 95% CI 1.9-3.8), impairment in activities of daily living (ADLs; OR 2.1, 95% CI 1.6-2.6), and impairment in instrumental activities of daily living (IADLs; OR 1.9, 95% CI 1.3-2.8). Potentially modifiable prognostic factors such as psychotropic medication use (OR 2.3, 95% CI 1.4-3.6) and smoking status (OR 1.8 95% CI 1.3-2.4) were also identified. Caregiver support was associated with lower odds of postoperative delirium (OR 0.69, 95% CI 0.52-0.91).

DISCUSSION

Though caution must be used in interpreting meta-analyses of non-randomized studies due to the potential influence of unmeasured confounding, we identified potentially modifiable prognostic factors including frailty and psychotropic medication use that should be targeted to optimize care.

Identifying older adults at risk of harm following elective surgery: a systematic review and meta-analysis

BACKGROUND

Elective surgeries can be associated with significant harm to older adults. The present study aimed to identify the prognostic factors associated with the development of postoperative complications among older adults undergoing elective surgery.

METHODS

Medline, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, and AgeLine were searched for articles published between inception and April 21, 2016. Prospective studies reporting prognostic factors associated with postoperative complications (composite outcome of medical and surgical complications), functional decline, mortality, post-hospitalization discharge destination, and prolonged hospitalization among older adults undergoing elective surgery were included. Study characteristics and prognostic factors associated with the outcomes of interest were extracted independently by two reviewers. Random effects meta-analysis models were used to derive pooled effect estimates for prognostic factors and incidences of adverse outcomes.

RESULTS

Of the 5692 titles and abstracts that were screened for inclusion, 44 studies (12,281 patients) reported on the following adverse postoperative outcomes: postoperative complications (n =28), postoperative mortality (n = 11), length of hospitalization (n = 21), functional decline (n = 6), and destination at discharge from hospital (n = 13). The pooled incidence of postoperative complications was 25.17% (95% confidence interval (CI) 18.03-33.98%, number needed to follow = 4). The geriatric syndromes of frailty (odds ratio (OR) 2.16, 95% CI 1.29-3.62) and cognitive impairment (OR 2.01, 95% CI 1.44-2.81) were associated with developing postoperative complications; however, there was no association with traditionally assessed prognostic factors such as age (OR 1.07, 95% CI 1.00-1.14) or American Society of Anesthesiologists status (OR 2.62, 95% CI 0.78-8.79). Besides frailty, other potentially modifiable prognostic factors, including depressive symptoms (OR 1.77, 95% CI 1.22-2.56) and smoking (OR 2.43, 95% CI 1.32-4.46), were also associated with developing postoperative complications.

CONCLUSION

Geriatric syndromes are important prognostic factors for postoperative complications. We identified potentially modifiable prognostic factors (e.g., frailty, depressive symptoms, and smoking) associated with developing postoperative complications that can be targeted preoperatively to optimize care.

Preoperative medication use and postoperative delirium: a systematic review

BACKGROUND

Medications are frequently reported as both predisposing factors and inducers of delirium. This review evaluated the available evidence and determined the magnitude of risk of postoperative delirium associated with preoperative medication use.

METHODS

A systematic search in Medline and EMBASE was conducted using MeSH terms and keywords for postoperative delirium and medication. Studies which included patients 18 years and older who underwent major surgery were included. The methodological quality of included studies was assessed independently by two authors using the Newcastle-Ottawa quality assessment scale for cohort studies.

RESULTS

Twenty-nine studies; 25 prospective cohort, three retrospective cohort and one post hoc analysis of RCT data were included. Only four specifically aimed to assess medicines as an independent predictor of delirium, all other studies included medicines among a number of potential predictors of delirium. Of the studies specifically testing the association with a medication class, preoperative use of beta-blockers (OR = 2.06[1.18-3.60]) in vascular surgery and benzodiazepines RR 2.10 (1.23-3.59) prior to orthopedic surgery were significant. However, evidence is from single studies only. Where medicines were included as one possible factor among many, hypnotics had a similar risk estimate to the benzodiazepine study, with one significant and one non-significant result. Nifedipine use prior to cardiac surgery was found to be significantly associated with delirium. The non-specific grouping of psychoactive medication use preoperatively was generally higher with an associated two-to-seven-fold higher risk of postoperative delirium, while only two studies included narcotics without other agents, with one significant and one non-significant result.

CONCLUSIONS

There was a limited number of high quality studies in the literature quantifying the direct association between preoperative medication use and postsurgical delirium. More studies are required to evaluate the association of specific preoperative medications on the risk of postoperative delirium so that comprehensive guidelines for medicine use prior to surgery can be developed to aid delirium prevention.

TRIAL REGISTRATION

This systematic review has been registered on PROSPERO International prospective register of systematic reviews (Registration number: CRD42016051245 ).

Post-Operative Cognitive Dysfunction: An exploration of the inflammatory hypothesis and novel therapies

Post-Operative Cognitive Dysfunction (POCD) is a highly prevalent condition with significant clinical, social and financial impacts for patients and their communities. The underlying pathophysiology is becoming increasingly understood, with the role of neuroinflammation and oxidative stress secondary to surgery and anaesthesia strongly implicated. This review aims to describe the putative mechanisms by which surgery-induced inflammation produces cognitive sequelae, with a focus on identifying potential novel therapies based upon their ability to modify these pathways.

Association between baseline cognitive impairment and postoperative delirium in elderly patients undergoing surgery for adult spinal deformity

OBJECTIVE Postoperative delirium is common in elderly patients undergoing spine surgery and is associated with a longer and more costly hospital course, functional decline, postoperative institutionalization, and higher likelihood of death within 6 months of discharge. Preoperative cognitive impairment may be a risk factor for the development of postoperative delirium. The aim of this study was to investigate the relationship between baseline cognitive impairment and postoperative delirium in geriatric patients undergoing surgery for degenerative scoliosis. METHODS Elderly patients 65 years and older undergoing a planned elective spinal surgery for correction of adult degenerative scoliosis were enrolled in this study. Preoperative cognition was assessed using the validated Saint Louis University Mental Status (SLUMS) examination. SLUMS comprises 11 questions, with a maximum score of 30 points. Mild cognitive impairment was defined as a SLUMS score between 21 and 26 points, while severe cognitive impairment was defined as a SLUMS score of ≤ 20 points. Normal cognition was defined as a SLUMS score of ≥ 27 points. Delirium was assessed daily using the Confusion Assessment Method (CAM) and rated as absent or present on the basis of CAM. The incidence of delirium was compared in patients with and without baseline cognitive impairment. RESULTS Twenty-two patients (18%) developed delirium postoperatively. Baseline demographics, including age, sex, comorbidities, and perioperative variables, were similar in patients with and without delirium. The length of in-hospital stay (mean 5.33 days vs 5.48 days) and 30-day hospital readmission rates (12.28% vs 12%) were similar between patients with and without delirium, respectively. Patients with preoperative cognitive impairment (i.e., a lower SLUMS score) had a higher incidence of postoperative delirium. One- and 2-year patient reported outcomes scores were similar in patients with and without delirium. CONCLUSIONS Cognitive impairment is a risk factor for the development of postoperative delirium. Postoperative delirium may be associated with decreased preoperative cognitive reserve. Cognitive impairment assessments should be considered in the preoperative evaluations of elderly patients prior to surgery.

Delayed Recall and Working Memory MMSE Domains Predict Delirium following Cardiac Surgery

BACKGROUND

Reduced preoperative cognition is a risk factor for postoperative delirium. The significance for type of preoperative cognitive deficit, however, has yet to be explored and could provide important insights into mechanisms and prediction of delirium.

OBJECTIVE

Our goal was to determine if certain cognitive domains from the general cognitive screener, the Mini-Mental State Exam (MMSE), predict delirium after cardiac surgery.

METHODS

Patients completed a preoperative MMSE prior to undergoing elective cardiac surgery. Following surgery, delirium was assessed throughout ICU stay using the Confusion Assessment Method for ICU delirium and the Richmond Agitation and Sedation Scale.

RESULTS

Cardiac surgery patients who developed delirium (n = 137) had lower total MMSE scores than patients who did not develop delirium (n = 457). In particular, orientation to place, working memory, delayed recall, and language domain scores were lower. Of these, only the working memory and delayed recall domains predicted delirium in a regression model adjusting for history of chronic obstructive pulmonary disease, age, sex, and duration of cardiopulmonary bypass. For each word not recalled on the three-word delayed recall assessment, the odds of delirium increased by 50%. For each item missed on the working memory index, the odds of delirium increased by 36%. Of the patients who developed delirium, 47% had a primary impairment in memory, 21% in working memory, and 33% in both domains. The area under the receiver operating characteristics curve using only the working memory and delayed recall domains was 0.75, compared to 0.76 for total MMSE score.

CONCLUSION

Delirium risk is greater for individuals with reduced MMSE scores on the delayed recall and working memory domains. Research should address why patients with memory and executive vulnerabilities are more prone to postoperative delirium than those with other cognitive limitations.

Neurologic complications of cardiac and vascular surgery

This chapter will provide an overview of the major neurologic complications of common cardiac and vascular surgeries, such as coronary artery bypass grafting and carotid endarterectomy. Neurologic complications after cardiac and vascular surgeries can cause significant morbidity and mortality, which can negate the beneficial effects of the intervention. Some of the complications to be discussed include ischemic and hemorrhagic stroke, seizures, delirium, cognitive dysfunction, cerebral hyperperfusion syndrome, cranial nerve injuries, and peripheral neuropathies. The severity of these complications can range from mild to lethal. The etiology of complications can include a variety of mechanisms, which can differ based on the type of cardiac or vascular surgery that is performed. Our knowledge about neuropathology, prevention, and management of surgical complications is growing and will be discussed in this chapter. It is imperative for clinicians to be familiar with these complications in order to narrow the differential diagnosis, start early management, anticipate the natural history, and improve outcomes.

Administration of lidocaine to prevent cognitive deficit in patients undergoing coronary artery bypass grafting and valve plasty: a systematic review and meta-analysis

INTRODUCTION

The administration of lidocaine to maintain cognitive function following coronary artery bypass grafting (CABG) and valve plasty is a controversial concept in terms of its effectiveness. We performed a systematic review to determine the effectiveness of treatment with lidocaine in preventing the occurrence of cognitive deficit after cardiac surgery. Area covered: To review the current literature on the subject, we searched the PubMed database and the Cochrane Library database (up to May 2015) and compiled a list of retrieved articles. Our final review includes only randomized controlled trials (RCTs) that compared lidocaine to a control (placebo) following CABG and valve plasty. Statistical analysis of the odds ratio (OR) and corresponding 95% confidence interval (CI) were used to determine the overall effectiveness of lidocaine for the prevention of cognitive deficit with both procedures. The Mantel-Haenszel method was used to pool data of the outcomes of cognitive deficit occurrence into fixed-effect model meta-analyses. Five RCTs were included in this study, with a total of 688 patients. Perioperative administration of lidocaine in patients undergoing cardiac surgery reduced occurrence of cognitive deficit (OR 0.583 [95% CI 0.438-0.777]; Z = -3.680; P = 0.00; I² = 52%). No significant difference in the early occurrence of cognitive deficit was revealed in patients after cardiac surgery (OR 0.909 [95% CI 0.600-1.376]; Z = -0.451; P = 0.652; I² = 11%). Expert commentary: Cognitive deficit associated with cardiac surgery is a common postoperative event. Lidocaine is contributed to a significantly reduced occurrence of cognitive deficit. Cognitive deficit management is recommended.

Dexmedetomidine reduces postoperative delirium after joint replacement in elderly patients with mild cognitive impairment

BACKGROUND AND AIMS

Postoperative delirium (POD) is a common and serious surgical complication among the elderly, especially in those with amnestic mild cognitive impairment (aMCI). Dexmedetomidine (DEX) is neuroprotective for delirium. In this study, we determined the effect of intravenously administered DEX during general anesthesia on POD in elderly aMCI patients undergoing elective hip joint or knee joint or shoulder joint replacement surgery.

METHODS

This was a prospective, randomized parallel-group study of aMCI (n = 80) and normal elderly patients (n = 120). Prior to surgery, all subjects underwent neuropsychological assessment and were assigned to one of four groups: the aMCI DEX group (MD group, n = 40), the aMCI normal saline group (MN group, n = 40), the control DEX group (CD group, n = 60), and the control normal saline group (CN group, n = 60). The confusion assessment method was used to screen POD on postoperative days 1, 3, and 7.

RESULTS

We found patients age was positively correlated with POD incidence in the MN group (p < 0.05) but not in the CN group (p < 0.05). DEX treatment significantly decreased POD incidence in both control and aMCI groups relative to their respective placebo groups (all p < 0.05). The fraction of patients whose normal cognitive function was not restored by day 7 after surgery was significantly higher in the MN group than the MD and CN groups (all p < 0.05).

CONCLUSIONS

These findings suggested that DEX treatment during surgery significantly reduced POD incidence in both normal and aMCI elderly patients, suggesting that it may be an effective option for the prevention of POD.

Cognitive and functional status predictors of delirium and delirium severity after coronary artery bypass graft surgery: an interim analysis of the Neuropsychiatric Outcomes After Heart Surgery study

BACKGROUND

Cognitive and functional impairment increase risk for post-coronary artery bypass graft (CABG) surgery delirium (PCD), but how much impairment is necessary to increase PCD risk remains unclear.

METHODS

The Neuropsychiatric Outcomes After Heart Surgery (NOAHS) study is a prospective, observational cohort study of participants undergoing elective CABG surgery. Pre-operative cognitive and functional status based on Clinical Dementia Rating (CDR) scale and neuropsychological battery are assessed. We defined mild cognitive impairment (MCI) based on either (1) CDR global score 0.5 (CDR-MCI) or (2) performance 1.5 SD below population means on any cognitive domain on neurocognitive battery (MCI-NC). Delirium was assessed daily post-operative day 2 through discharge using the confusion assessment method (CAM) and delirium index (DI). We investigate whether MCI - either definition - predicts delirium or delirium severity.

RESULTS

So far we have assessed 102 participants (mean age 65.1 ± 9; male: 75%) for PCD. Twenty six participants (25%) have MCI-CDR; 38 (62% of those completing neurocognitive testing) met MCI-NC criteria. Fourteen participants (14%) developed PCD. After adjusting for age, sex, comorbidity, and education, MCI-CDR, MMSE, and Lawton IADL score predicted PCD on logistic regression (OR: 5.6, 0.6, and 1.5, respectively); MCI-NC did not (OR [95% CI]: 11.8 [0.9, 151.4]). Using similarly adjusted linear regression, MCI-CDR, MCI-NC, CDR sum of boxes, MMSE, and Lawton IADL score predicted delirium severity (adjusted R(2): 0.26, 0.13, 0.21, 0.18, and 0.32, respectively).

CONCLUSIONS

MCI predicts post-operative delirium and delirium severity, but MCI definition alters these relationships. Cognitive and functional impairment independently predict post-operative delirium and delirium severity.

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.

Preoperative Cognitive and Frailty Screening in the Geriatric Surgical Patient: A Narrative Review

PURPOSE

The identification of older patients who may have deficits in cognitive or functional domains will become more pressing as increasing numbers of these patients present for preoperative evaluations. The number of older adults with deficiencies in these areas is projected to grow, and more of these patients will present for assessment in preoperative clinics with the expectation that surgeries will be performed.

METHODS

We review current outcomes data for preoperative cognitive impairment and frailty.

FINDINGS

We point to a number of directions research is taking as systems for the prevention of postoperative cognitive and functional decline are being developed. We also discuss the current status of screening and examine potential instruments that can be used in the setting of the preanesthesia clinic.

IMPLICATIONS

Clinicians may anticipate that geriatric screening tools focused on cognitive and functional domains will play a direct role in the ongoing evolution of presurgical assessment and triage.

Different MMSE Score Is Associated with Postoperative Delirium in Young-Old and Old-Old Adults

Background

Postoperative delirium is one of the most common postoperative complications in geriatric patients. Mini-mental state examination (MMSE) assesses cognitive function in patients and is associated with postoperative delirium. However, whether there is an age-dependent relationship between preoperative MMSE score and postoperative delirium remains unknown.

Methods

We therefore set out to investigate the association between preoperative MMSE score and postoperative delirium in young-old (≤80 year-old, 75.46±4.69 years, 27.0% male, n = 63) and old-old (>80 year-old, 84.51±3.46 years, 20.9% male, n = 67) participants, who had repairs of hip fractures under general anesthesia. The Confusion Assessment Method and Memorial Delirium Assessment Scale were administrated before surgery, and on the first, second and fourth days after surgery, to assess the incidence and severity of the delirium, respectively. A receiver operating characteristic curve analysis was used to calculate the optimal cutoff score of MMSE in predicting postoperative delirium.

Results

Thirty-four (26.2%) of 130 patients (80.12±6.12 years, 23.8% male) developed postoperative delirium. Preoperative MMSE scores were negatively associated with higher incidences and greater severity of postoperative delirium. The optimal cutoff scores of MMSE associated with postoperative delirium for young-old and old-old participants were 18.4 and 21.4, with a sensitivity of 60% and 83.8%, and a specificity of 92.5% and 62.8%, respectively.

Conclusion

The data demonstrated the optimal cutoff score of MMSE associated with postoperative delirium in young-old adults might be lower than that in old-old adults. Pending further investigation, these findings suggest that the association between preoperative MMSE score and postoperative delirium is age-dependent.

Risk factors for delirium after on-pump cardiac surgery: a systematic review

Introduction

As evidence-based effective treatment protocols for delirium after cardiac surgery are lacking, efforts should be made to identify risk factors for preventive interventions. Moreover, knowledge of these risk factors could increase validity of etiological studies in which adjustments need to be made for confounding variables. This review aims to systematically identify risk factors for delirium after cardiac surgery and to grade the evidence supporting these associations.

Method

A prior registered systematic review was performed using EMBASE, CINAHL, MEDLINE and Cochrane from 1990 till January 2015 (http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42014007371). All studies evaluating patients for delirium after cardiac surgery with cardiopulmonary bypass (CPB) using either randomization or multivariable data analyses were included. Data was extracted and quality was scored in duplicate. Heterogeneity impaired pooling of the data; instead a semi-quantitative approach was used in which the strength of the evidence was graded based on the number of investigations, the quality of studies, and the consistency of the association reported across studies.

Results

In total 1462 unique references were screened and 34 were included in this review, of which 16 (47 %) were graded as high quality. A strong level of evidence for an association with the occurrence of postoperative delirium was found for age, previous psychiatric conditions, cerebrovascular disease, pre-existent cognitive impairment, type of surgery, peri-operative blood product transfusion, administration of risperidone, postoperative atrial fibrillation and mechanical ventilation time. Postoperative oxygen saturation and renal insufficiency were supported by a moderate level of evidence, and there is no evidence that gender, education, CPB duration, pre-existent cardiac disease or heart failure are risk factors.

Conclusion

Of many potential risk factors for delirium after cardiac surgery, for only 11 there is a strong or moderate level of evidence. These risk factors should be taken in consideration when designing future delirium prevention strategies trials or when controlling for confounding in future etiological studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1060-0) contains supplementary material, which is available to authorized users.

Mild cognitive impairment with associated inflammatory and cortisol alterations as independent risk factor for postoperative delirium

AIMS

The present study aimed to determine the impact of mild cognitive impairment (MCI) on the development of postoperative delirium and, secondly, to assess the association between MCI and raised perioperative cortisol, cytokine, cobalamin and homocysteine levels.

METHODS

The study recruited 113 consecutive adult patients scheduled for cardiac surgery with cardiopulmonary bypass. The patients were examined preoperatively with the Montreal Cognitive Assessment and Trail Making Test. A diagnosis of MCI was established based upon the criteria of the National Institute on Aging and Alzheimer's Association. Patients were screened for delirium within the first 5 days postoperatively.

RESULTS

MCI was diagnosed in 24.8% of the patients, whereas the frequency of delirium was 36%. A multivariate analysis demonstrated that individuals with MCI were at a significantly higher risk of postoperative delirium (OR = 6.33, p = 0.002). Preoperative cortisol, postoperative cortisol and IL-2 plasma levels were higher in the MCI group as compared to non-MCI subjects.

CONCLUSION

MCI is associated with a higher risk of postoperative delirium. Perioperative cortisol and inflammatory alterations observed in MCI may provide a physiological explanation for this increased risk.

Diagnostic and treatment practices of delirium in a general hospital

BACKGROUND

Despite the increase in research on delirium, it remains underdiagnosed and difficult to manage, and the outcome is poor especially in older people.

AIMS

To identify the clinically diagnosed rates of delirium, the possible aetiologies, to describe treatment, number and type of psychotropic medication used and to investigate the reasons for referral to a liaison psychiatric team.

METHODS

Retrospective study of medical records of inpatients admitted to Sligo Regional Hospital during an 18-month period.

RESULTS

One hundred and fifty-six files had a documentation of delirium (time prevalence 2%). Mean age of the sample was 82 years (SD = 7.2), 66 (42%) were male. Sixty-nine (44.2%) of the total sample had a previous history of dementia, and 57 (36.5%) had a previous history of delirium. In 67 (43.2%) samples, the cause was infection, while in 4, no specific cause was identified. Ninety (58%) were referred to the liaison service, but only in 26 (28.9 %), the reason for referral was "acute confusion" or "delirium". In a majority of referrals, the reason was an affective disorder more often depression. There were no significant differences between delirium subtypes and referrals (χ(2) = 3.868, df 3, p = 0.28). Examination of the amount of antipsychotics prescribed before, during and after delirium shows that there was a significant increase in use during the delirium (χ(2) = 17.512, df 8, p = 0.025) and decrease in z-hypnotics medication (zopiclone/zolpidem), (χ(2) = 20.114, df 4, p < 0.001), while benzodiazepines and antidepressants remained the same.

CONCLUSIONS

Delirium is often misdiagnosed and unrecognized in hospital settings; however, when identified the pharmacological management is appropriate.

Postoperative delirium following transcatheter aortic valve implantation: a historical cohort study

PURPOSE

Transcatheter aortic valve implantation (TAVI) techniques show favourable survival outcomes in high-risk patients, but the incidence of postoperative delirium is unknown. We conducted a historical cohort study to compare postoperative delirium in retrograde transfemoral (TF) versus anterograde transapical (TA) TAVI procedures. We also sought to identify independent predictors of delirium following TAVI.

METHODS

We performed a retrospective chart review on all patients who underwent TF (n = 77) or TA (n = 45) TAVI during 2008 and 2009 at St. Paul's Hospital (Vancouver, BC, Canada), the pioneering centre for these procedures. The primary outcome was a documented physician diagnosis of delirium. Abstracted data included information on demographics, medical history, surgical procedure, anesthesia, and postoperative care. We employed a multivariable logistic regression to identify independent predictors of delirium.

RESULTS

Delirium occurred in 12% of TF patients vs 53% of TA patients (P < 0.001). Preoperatively, the groups differed significantly in the rates of hypertension, pulmonary hypertension, dyslipidemia, peripheral vascular disease, congestive heart failure, previous myocardial infarction, and memory impairment. Differences in anesthetic management were also observed between the TF vs TA groups regarding inhalational anesthetics, opioids, neuromuscular blockers, antihemorrhagic drugs, and antibiotics. Independent predictors for delirium after TAVI included coronary artery disease (odds ratio [OR] 12.7; 95% confidence interval [CI] 1.0 to 154.9), cognitive impairment (OR 6.5; 95% CI 1.8 to 23.2), and cardiac arrhythmia (OR 3.5; 95% CI 1.1 to 11.6). Compared to the TF approach, TA-TAVI independently increased the risk of delirium (OR 13.8; 95% CI 3.3 to 59.0).

CONCLUSIONS

Patients undergoing TA-TAVI had a markedly increased incidence of postoperative delirium compared with patients undergoing TF-TAVI.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Evaluation of the prevalence and risk factors of delirium in cardiac surgery ICU

INTRODUCTION

Delirium is defined as an acute cognitive disorder presenting with fluctuation in cognition, apathy and non-organized thinking. It may increase morbidity, mortality, ICU stay and cost. In patients who underwent heart surgery delirium may increase post-operative complications such as respiratory insufficiency, sternum instability and need to re-operation of the sternum. The aim of this study was to evaluate the prevalence and risk factors of delirium in patients admitted to cardiac surgery.

MATERIALS AND METHODS

18 years or older patients who had undergone cardiac surgeries and stayed for more than 24 hours in ICU following surgery were recruited. All subjects were assessed for signs &amp; symptoms of delirium using CAM-ICU and its risk factors. All data were analyzed by SPSS 16 at the end of the study.

RESULTS

The prevalence of delirium in these patients was 23.5% (47 patients). The mean age of patients with delirium was more than other patients (P=0.001). The Incidence of delirium in the patients with cardiopulmonary bypass surgery (CPB) was higher than the patients without CPB (P=0.01). The Incidence of delirium in the patients with Atrial fibrillation was higher than patients without it (P=0.002). The Incidence of delirium in the patients with CVA history was higher than the patients without CVA history (P=0.032). The mean time of mechanical ventilation in the delirious patients was more than other patients (P=0.01).

CONCLUSION

Older Age, CPB, history of CVA, Atrial Fibrillation, and prolonged mechanical ventilation are considered as the risk factors of delirium in cardiac surgery patients.

Predisposing and precipitating factors of delirium after cardiac surgery: a prospective observational cohort study

OBJECTIVE

To comprehensively assess pre-, intra-, and postoperative delirium risk factors as potential targets for intervention.

BACKGROUND

Delirium after cardiac surgery is associated with longer intensive care unit (ICU) stay, and poorer functional and cognitive outcomes. Reports on delirium risk factors so far did not cover the full range of patients' presurgical conditions, intraoperative factors, and postoperative course.

METHODS

After written informed consent, 221 consecutive patients ≥ 50 years scheduled for cardiac surgery were assessed for preoperative cognitive performance, and functional and physical status. Clinical and biochemical data were systematically recorded perioperatively.

RESULTS

Of the 215 patients remaining for analysis, 31% developed delirium in the intensive care unit. Using logistic regression models, older age [73.3 (71.2-75.4) vs 68.5 (67.0-70.0); P = 0.016], higher Charlson's comorbidity index [3.0 (1.5-4.0) vs 2.0 (1.0-3.0) points; P = 0.009], lower Mini-Mental State Examination (MMSE) score (MMSE, [27 (23-29) vs 28 (27-30) points; P = 0.021], length of cardiopulmonary bypass (CPB) [CPB; 133 (112-163) vs 119 (99-143) min; P = 0.004], and systemic inflammatory response syndrome in the intensive care unit [25 (36.2%) vs 13 (8.9%); P = 0.001] were independently associated with delirium. Combining age, MMSE score, Charlson's comorbidity index, and length of CPB in a regression equation allowed for a prediction of postoperative delirium with a sensitivity of 71.19% and a specificity of 76.26% (receiver operating analysis, area under the curve: 0.791; 95% confidence interval: 0.727-0.845).

CONCLUSIONS

Further research will evaluate if modification of these risk factors prevents delirium and improves outcomes.

Pre-existing cerebral infarcts as a risk factor for delirium after coronary artery bypass graft surgery

OBJECTIVES

Delirium is a common and critical clinical syndrome in older patients. We examined whether abnormalities in the brain that could be assessed by magnetic resonance imaging predisposed patients to develop delirium after coronary artery bypass graft surgery. We also analysed the association between delirium and cognitive dysfunction after coronary artery bypass graft surgery.

METHODS

Data were collected prospectively on 153 patients aged 60 years or older who consecutively underwent elective isolated coronary artery bypass graft surgery. All patients were assessed for prior cerebral infarctions and craniocervical artery stenosis by magnetic resonance imaging (MRI) and angiography of their brains. Atherosclerosis of the ascending aorta was examined by epiaortic ultrasound at the time of surgery. Individual cognitive status was measured using four tests in all the patients before surgery and on the seventh postoperative day. A single psychiatrist diagnosed delirium using the Diagnostic and Statistical Manual of Mental Disorders 4th edition IV criteria.

RESULTS

Postoperative delirium occurred in 16 patients (10.5%). Compared with patients who did not develop postoperative delirium, delirious patients had significantly higher rates of peripheral artery disease, preoperative decline in global cognitive function and pre-existing multiple cerebral infarctions on MRI. In addition, 9 (56%) of the delirious patients suffered postoperative cognitive dysfunction. Stepwise logistic regression analysis found significant independent predictors of postoperative delirium to be preoperative cerebral infarcts on MRI (odds ratio [OR], 2.26; 95% confidence interval [CI] 1.10-4.78), preoperative decline in global cognitive function (OR 4.54; 95% CI 1.21-16.51) and atherosclerosis of the ascending aorta (OR 2.44; 95% CI 1.03-5.62).

CONCLUSIONS

Our findings suggested that postoperative delirium was associated with pre-existing multiple cerebral infarctions on MRI, preoperative decline in global cognitive function and ascending aortic atherosclerosis in elderly patients undergoing coronary artery bypass graft surgery and increased risk of postoperative cognitive dysfunction.

Meta-analysis of factors which influence delirium following cardiac surgery

BACKGROUND

The aim of this study is to determine the risk factors of delirium after cardiac surgery.

METHODS

A systematic literature search of MEDLINE, EMBASE, the Cochrane Library, and Science Citation Index limited to 2008 to 2011 and review of studies was conducted. Eligible studies were of randomized controlled trials or cohort studies, using delirium assessment tool, reporting at least one risk factor associated with delirium, and available to full text.

RESULTS

The search identified 106 potentially relevant publications; only 25 met selection criteria. Our systematic review revealed 33 risk factors: 17 predisposing and 16 precipitating factors for delirium after elective cardiac surgery. The most established predisposing risk factors were age, depression, and history of stroke, cognitive impairment, diabetes mellitus, and atrial fibrillation. The most established precipitating risk factors were duration of surgery, prolonged intubation, surgery type, red blood cell transfusion, elevation of inflammatory markers and plasma cortisol level, and postoperative complications. Moreover, sedation with dexmedetomidine may significantly predict the absence of postoperative delirium.

CONCLUSIONS

Postoperative delirium is related to several risk factors following cardiac surgery. Sedation with dexmedetomidine and fast-track weaning protocols may decrease the incidence of delirium in cardiac surgical patients.

Cognitive and functional predictors and sequelae of postoperative delirium in elderly patients undergoing elective joint arthroplasty

BACKGROUND

Postoperative delirium (POD) is common in the elderly and associated with adverse outcomes. The cognitive and functional sequelae of POD in elective surgical patients are not known. We sought to determine whether (1) lower scores on sensitive neurocognitive tests are an independent risk factor for POD in elderly surgical patients, and (2) POD predicts cognitive and functional decline 3 months postoperatively.

METHODS

We conducted a prospective, cohort study on patients ≥65 years old undergoing total hip or knee arthroplasty. Participants underwent preoperative neurocognitive and functional testing. POD was diagnosed using the Confusion Assessment Method. Patients who developed POD and matched controls underwent repeat neurocognitive and functional testing 3 months after surgery.

RESULTS

Four hundred eighteen patients met entry criteria, and 42 (10%) developed POD. There were no differences in baseline Mini-Mental State Examination scores, alcohol abuse, depression, and verbal intelligence between groups. Independent predictors of POD included age, history of psychiatric illness, decreased functional status, and decreased verbal memory. For all tests, changes from before to 3 months after surgery were similar between those patients with POD and matched controls.

CONCLUSIONS

Subtly reduced preoperative neurocognitive and functional status predict POD. However, in the small group that developed POD, there was no evidence of cognitive and functional decline 3 months after surgery. POD is associated with decreased preoperative cognitive reserve but, in elderly elective surgical patients, may be without adverse cognitive or functional sequelae 3 months postoperatively.