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Delirium is one of the most commonly occurring postoperative complications in older adults. It occurs due to the vulnerability of cerebral functioning to pathophysiological stressors. Identification of those at increased risk of developing delirium early in the surgical pathway provides an opportunity for modification of predisposing and precipitating risk factors and effective shared decision-making. No single delirium prediction tool is used widely in surgical settings. Multi-component interventions to prevent delirium involve structured risk factor modification supported by geriatrician input; these are clinically efficacious and cost effective. Barriers to the widespread implementation of such complex interventions exist, resulting in an 'implementation gap'. There is a lack of evidence for pharmacological prophylaxis for the prevention of delirium. Current evidence suggests that avoidance of peri-operative benzodiazepines, careful titration of anaesthetic depth guided by processed electroencephalogram monitoring and treatment of pain are the most effective strategies to minimise the risk of delirium. Addressing postoperative delirium requires a collaborative, whole pathway approach, beginning with the early identification of those patients who are at risk. The research agenda should continue to examine the potential for pharmacological prophylaxis to prevent delirium while also addressing how successful models of delirium prevention can be translated from one setting to another, underpinned by implementation science methodology., (© 2022 Association of Anaesthetists.)

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., Competing Interests: Conflicts of Interest: See Disclosures at the end of the article., (Copyright © 2021 International Anesthesia Research Society.)

Background: Reducing depth of anesthesia and anesthetic exposure may help prevent delirium, but trials have been conflicting. Most studies were conducted under general anesthesia or in cognitively impaired patients. It is unclear whether reducing depth of anesthesia beyond levels consistent with general anesthesia reduces delirium in cognitively intact patients. The authors' objective was to determine whether a bundled approach to reduce anesthetic agent exposure as determined by Bispectral Index (BIS) values (spinal anesthesia with targeted sedation based on BIS values) compared with general anesthesia (masked BIS) reduces delirium., Methods: Important eligibility criteria for this parallel-arm randomized trial were patients 65 yr or greater undergoing lumbar spine fusion. The intervention group received spinal anesthesia with targeted sedation to BIS greater than 60 to 70. The control group received general anesthesia (masked BIS). The primary outcome was delirium using the Confusion Assessment Method daily through postoperative day 3, with blinded assessment., Results: The median age of 217 patients in the analysis was 72 (interquartile range, 69 to 77). The median BIS value in the spinal anesthesia with targeted sedation based on BIS values group was 62 (interquartile range, 53 to 70) and in the general anesthesia with masked BIS values group was 45 (interquartile range, 41 to 50; P < 0.001). Incident delirium was not different in the spinal anesthesia with targeted sedation based on BIS values group (25.2% [28 of 111] vs. the general anesthesia with masked BIS values group (18.9% [20 of 106]; P = 0.259; relative risk, 1.22 [95% CI, 0.85 to 1.76]). In prespecified subgroup analyses, the effect of anesthetic strategy differed according to the Mini-Mental State Examination, but not the Charlson Comorbidity Index or age. Two strokes occurred among patients receiving spinal anesthesia and one death among patients receiving general anesthesia., Conclusions: Spinal anesthesia with targeted sedation based on BIS values compared with general anesthesia with masked BIS values did not reduce delirium after lumbar fusion., (Copyright © 2021, the American Society of Anesthesiologists. All Rights Reserved.)

Abstract: To determine the effect of recorded maternal voice on emergence delirium (ED) in children under general anesthesia, a three-group randomized trial was conducted. A total of 102 children were randomly assigned to mother recording group (n = 34), stranger recording group (n = 34), and control group (n = 34). All subjects were assessed for ED with the Pediatric Anesthesia Emergence Delirium Scale; pain with the Face, Legs, Activity, Cry, and Consolability Scale; and various recovery durations and hemodynamic parameters at six time points. One-way analysis of variance showed that the ED score was significantly lower in the mother recording group (F = 18.520, p = 0.000), and statistical significance was observed in the duration of eye opening (p = 0.001) and tracheal extubation (p = 0.002). Generalized estimating equations observed interaction effects on heart rate and blood pressure (both p = 0.000). Mothers' voice might help reduce ED in children under general anesthesia., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: It is unclear how preoperative neurodegeneration and postoperative changes in EEG delta power relate to postoperative delirium severity. We sought to understand the relative relationships between neurodegeneration and delta power as predictors of delirium severity., Methods: We undertook a prospective cohort study of high-risk surgical patients (>65 yr old) to identify predictors of peak delirium severity (Delirium Rating Scale-98) with twice-daily delirium assessments (NCT03124303). Participants (n=86) underwent preoperative MRI; 54 had both an MRI and a postoperative EEG. Cortical thickness was calculated from the MRI and delta power from the EEG., Results: In a linear regression model, the interaction between delirium status and preoperative mean cortical thickness (suggesting neurodegeneration) across the entire cortex was a significant predictor of delirium severity (P<0.001) when adjusting for age, sex, and performance on preoperative Trail Making Test B. Next, we included postoperative delta power and repeated the analysis (n=54). Again, the interaction between mean cortical thickness and delirium was associated with delirium severity (P=0.028), as was postoperative delta power (P<0.001). When analysed across the Desikan-Killiany-Tourville atlas, thickness in multiple individual cortical regions was also associated with delirium severity., Conclusions: Preoperative cortical thickness and postoperative EEG delta power are both associated with postoperative delirium severity. These findings might reflect different underlying processes or mechanisms., Clinical Trial Registration: NCT03124303., (Copyright © 2021 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Background: Emergence delirium (ED) in children after general anaesthesia causes significant distress in patients, their family members, and clinicians; however, electroencephalogram (EEG) markers predicting ED have not been fully investigated., Methods: This prospective, single-centre observational study enrolled children aged 2-10 yr old under sevoflurane anaesthesia. ED was assessed according to Diagnostic and Statistical Manual of Mental Disorders (DSM) IV or 5 criteria. The relative power of low-frequency (delta and theta) and high-frequency (alpha and beta) EEG waves during the emergence period was compared between the children with and without ED. The linear relationships between the relative power and peak Paediatric Assessment of Emergence Delirium (PAED) score were investigated., Results: Among the 60 patients, 22 developed ED (ED group), whereas the other 38 did not (non-ED group). The relative power of the delta wave was higher (mean [standard deviation], 0.579 [0.083] vs 0.453 [0.090], respectively, P<0.001) in the ED group, whereas that of the alpha and beta waves was lower in the ED group, than in the non-ED group (0.155 [0.063] vs 0.218 [0.088], P=0.005 and 0.114 [0.069] vs 0.186 [0.070], P<0.001, respectively). The areas under the receiver operating characteristic curves of the relative power of the delta wave, low-to-high frequency power ratio, and delta-to-alpha ratio were 0.837 (95% confidence interval, 0.737-0.938), 0.835 (0.735-0.934), and 0.768 (0.649-0.887), respectively. The relative power of the delta wave and the two ratios had a positive linear relationship with the peak PAED scores., Conclusions: Paediatric patients developing ED have increased low-frequency (delta) frontal EEG activity with reduced high-frequency (alpha and beta) activity during emergence from general anaesthesia., Clinical Trial Registration: NCT03797274., (Copyright © 2020 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Background: Cerebral oximetry has been widely used to measure regional oxygen saturation in brain tissue, especially during cardiac surgery. Despite its popularity, there have been inconsistent results on the use of cerebral oximetry during cardiac surgery, and few studies have evaluated cerebral oximetry during off pump coronary artery bypass graft surgery (OPCAB)., Methods: To evaluate the relationship between intraoperative cerebral oximetry and postoperative delirium in patients who underwent OPCAB, we included 1439 patients who underwent OPCAB between October 2004 and December 2016 and among them, 815 patients with sufficient data on regional cerebral oxygen saturation (rSO 2 ) were enrolled in this study. We retrospectively analyzed perioperative variables and the reduction in rSO 2 below cut-off values of 75, 70, 65, 60, 55, 50, 45, 40, and 35%. Furthermore, we evaluated the relationship between the reduction in rSO 2 and postoperative delirium., Results: Delirium occurred in 105 of 815 patients. In both univariable and multivariable analyses, the duration of rSO 2 reduction was significantly longer in patients with delirium at cut-offs of < 50 and 45% (for every 5 min, adjusted odds ratio (OR) 1.007 [95% Confidence interval (CI) 1.001 to 1.014] and adjusted OR 1.012 [1.003 to 1.021]; p = 0.024 and 0.011, respectively). The proportion of patients with a rSO 2 reduction < 45% was significantly higher among those with delirium (adjusted OR 1.737[1.064 to 2.836], p = 0.027)., Conclusions: In patients undergoing OPCAB, intraoperative rSO 2 reduction was associated with postoperative delirium. Duration of rSO 2 less than 50% was 40% longer in the patients with postoperative delirium. The cut-off value of intraoperative rSO 2 that associated with postoperative delirium was 50% for the total patient population and 55% for the patients younger than 68 years.

Background: A number of recent studies have reported an association between intraoperative burst suppression and postoperative delirium. These studies suggest that anesthesia-induced burst suppression may be an indicator of underlying brain vulnerability. A prominent feature of electroencephalogram (EEG) under propofol and sevoflurane anesthesia is the frontal alpha oscillation. This frontal alpha oscillation is known to decline significantly during aging and is generated by prefrontal brain regions that are particularly prone to age-related neurodegeneration. Given that burst suppression and frontal alpha oscillations are both associated with brain vulnerability, we hypothesized that anesthesia-induced frontal alpha power could also be associated with burst suppression., Methods: We analyzed EEG data from a previously reported cohort in which 155 patients received propofol (n = 60) or sevoflurane (n = 95) as the primary anesthetic. We computed the EEG spectrum during stable anesthetic maintenance and identified whether or not burst suppression occurred during the anesthetic. We characterized the relationship between burst suppression and alpha power using logistic regression. We proposed 5 different models consisting of different combinations of potential contributing factors associated with burst suppression: (1) a Base Model consisting of alpha power; (2) an Extended Mechanistic Model consisting of alpha power, age, and drug dosing information; (3) a Clinical Confounding Factors Model consisting of alpha power, hypotension, and other confounds; (4) a Simplified Model consisting only of alpha power and propofol bolus administration; and (5) a Full Model consisting of all of these variables to control for as much confounding as possible., Results: All models show a consistent significant association between alpha power and burst suppression while adjusting for different sets of covariates, all with consistent effect size estimates. Using the Simplified Model, we found that for each decibel decrease in alpha power, the odds of experiencing burst suppression increased by 1.33-fold., Conclusions: In this study, we show how a decrease in anesthesia-induced frontal alpha power is associated with an increased propensity for burst suppression, in a manner that captures individualized information above and beyond a patient's chronological age. Lower frontal alpha band power is strongly associated with higher propensity for burst suppression and, therefore, potentially higher risk of postoperative neurocognitive disorders. We hypothesize that low frontal alpha power and increased propensity for burst suppression together characterize a "vulnerable brain" phenotype under anesthesia that could be mechanistically linked to brain metabolism, cognition, and brain aging.

BACKGROUND Postoperative delirium (POD) is a frequent complication in elderly patients, usually occurring within a few days after surgery. This study investigated the effect of lung-protective ventilation (LPV) on POD in elderly patients undergoing spinal surgery and the mechanism by which LPV suppresses POD. MATERIAL AND METHODS Seventy-one patients aged ≥65 years were randomized to receive LPV or conventional mechanical ventilation (MV), consisting of intermittent positive pressure ventilation following induction of anesthesia. The tidal volume in patients who received MV was 8 ml/kg predicted body weight (PBW), and the ventilation frequency was 12 times/min. The tidal volume in patients who received LPV was 6 ml/kg PBW, the positive end-expiratory pressure was 5 cmH₂O, and the ventilation frequency was 15 times/min, with a lung recruitment maneuver performed every 30 min. Blood samples were collected immediately before anesthesia induction (T₀), 10 min (T₁) and 60 min (T₂) after turning over, immediately after the operation (T₃), and 15 min after extubation (T₄) for blood gas analysis. Simultaneous cerebral oxygen saturation (rSO₂) and cerebral desaturation were recorded. Preoperative and postoperative serum concentrations of interleukin (IL)-6, IL-10 and glial fibrillary acidic protein (GFAP) were measured by ELISA. POD was assessed by nursing delirium screening score. RESULTS Compared with the MV group, pH was lower and PaCO₂ higher in the LPV group at T₂. In addition PaO₂, SaO₂, and PaO₂/FiO₂ were higher at T₁, and T₄, and rSO₂ was higher at T₃, and T₄ in the LPV than in the MV group (P<0.05 each). Postoperative serum GFAP and IL-6 were lower and IL-10 higher in the LPV group. The incidences of cerebral desaturation and POD were significantly lower in the LPV group (P<0.05). CONCLUSIONS LPV may reduce POD in elderly patients undergoing spinal surgery by inhibiting inflammation and improving cerebral oxygen metabolism.

Background: Postoperative delirium is a common complication that hinders recovery after surgery. Intraoperative electroencephalogram suppression has been linked to postoperative delirium, but it is unknown if this relationship is causal or if electroencephalogram suppression is merely a marker of underlying cognitive abnormalities. The hypothesis of this study was that intraoperative electroencephalogram suppression mediates a nonzero portion of the effect between preoperative abnormal cognition and postoperative delirium., Methods: This is a prespecified secondary analysis of the Electroencephalography Guidance of Anesthesia to Alleviate Geriatric Syndromes (ENGAGES) randomized trial, which enrolled patients age 60 yr or older undergoing surgery with general anesthesia at a single academic medical center between January 2015 and May 2018. Patients were randomized to electroencephalogram-guided anesthesia or usual care. Preoperative abnormal cognition was defined as a composite of previous delirium, Short Blessed Test cognitive score greater than 4 points, or Eight Item Interview to Differentiate Aging and Dementia score greater than 1 point. Duration of intraoperative electroencephalogram suppression was defined as number of minutes with suppression ratio greater than 1%. Postoperative delirium was detected via Confusion Assessment Method or chart review on postoperative days 1 to 5., Results: Among 1,113 patients, 430 patients showed evidence of preoperative abnormal cognition. These patients had an increased incidence of postoperative delirium (151 of 430 [35%] vs.123 of 683 [18%], P < 0.001). Of this 17.2% total effect size (99.5% CI, 9.3 to 25.1%), an absolute 2.4% (99.5% CI, 0.6 to 4.8%) was an indirect effect mediated by electroencephalogram suppression, while an absolute 14.8% (99.5% CI, 7.2 to 22.5%) was a direct effect of preoperative abnormal cognition. Randomization to electroencephalogram-guided anesthesia did not change the mediated effect size (P = 0.078 for moderation)., Conclusions: A small portion of the total effect of preoperative abnormal cognition on postoperative delirium was mediated by electroencephalogram suppression. Study precision was too low to determine if the intervention changed the mediated effect.

Cognitive recovery after anaesthesia and surgery is a concern for older adults, their families, and caregivers. Reports of patients who were 'never the same' prompted a scientific inquiry into the nature of what patients have experienced. In June 2018, the ASA Brain Health Initiative held a summit to discuss the state of the science on perioperative cognition, and to create an implementation plan for patients and providers leveraging the current evidence. This group included representatives from the AARP (formerly the American Association of Retired Persons), American College of Surgeons, American Heart Association, and Alzheimer's Association Perioperative Cognition and Delirium Professional Interest Area. This paper summarises the state of the relevant clinical science, including risk factors, identification and diagnosis, prognosis, disparities, outcomes, and treatment of perioperative neurocognitive disorders. Finally, we discuss gaps in current knowledge with suggestions for future directions and opportunities for clinical and translational projects., (Copyright © 2019 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Objectives: To evaluate  the effectiveness of sugammadex in reducing or eliminating postoperative agitation levels, early respiratory complications and nausea/vomiting in children undergoing adenotonsillectomy., Methods: A total of 70 patients (age range: 5-13 years) who underwent an adenotonsillectomy  in the Otolaryngology Clinic, Sakarya University, Sakarya, Turkey between May 2015 and September 2017 were included in the study. The patients were randomized into a sugammadex group (Group S) and a neostigmine + atropine (Group N); each group contained 35 patients. Time to extubation, postoperative agitation levels, and early postoperative complications were evaluated and recorded. Data from both groups were statistically evaluated and compared., Results: The time to extubation was significantly shorter in Group S than Group N (p less than 0.05). Agitation scores during recovery were significantly lower in Group S than Group N (p less than 0.05). More complications were observed in Group N than in Group S; the number of patients seen coughing and experiencing nausea/vomiting in Group S was statistically significantly lower (p less than 0.05)., Conclusion: This study demonstrated that the use of sugammadex results in less time to recovery and less agitation in comparison to conventional administration of neostigmine + atropine in the reversal of neuromuscular blocking after adenotonsillectomy.

The pathophysiology of emergence delirium (ED) remains a mystery. Using a case study approach, ED is discussed from a clinical perspective. The case is a 4-year-old male who had myringotomy tube placement while anesthetized with sevoflurane. The negative outcome for this child is presented. The epidemiology of the phenomena is reviewed and definitions are examined. Several methods to assess ED are presented, accompanied by a discussion of the development of assessment tools. Research findings are included that address the possible causes of ED including preoperative anxiety, rapid awakening, pain, and a predisposition for this phenomenon in certain children. Various interventions, both pharmacologic and nonpharmacologic are considered. The impact of anesthesia on pediatric brain development is discussed and finally some possible solutions are hypothesized., (Copyright © 2018 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.)

Background: Our objective was to evaluate if changes in on-pump cerebral blood flow, relative to the pre-bypass baseline, are associated with the risk for postoperative delirium (POD) following cardiac surgery., Methods: In 47 consecutive adult patients, right middle cerebral artery blood flow velocity (MCAV) was assessed using transcranial Doppler sonography. Individual values, measured during cardiopulmonary bypass (CPB), were normalized to the pre-bypass baseline value and termed MCAV rel . An MCAV rel  > 100% was defined as cerebral hyperperfusion. Prevalence of POD was assessed using the Confusion Assessment Method for the Intensive Care Unit., Results: Overall prevalence of POD was 27%. In the subgroup without POD, 32% of patients had experienced relative cerebral hyperperfusion during CPB, compared to 67% in the subgroup with POD (p < 0.05). The mean averaged MCAV rel was 90 (±21) % in the no-POD group vs. 112 (±32) % in the POD group (p < 0.05), and patients developing delirium experienced cerebral hyperperfusion during CPB for about 39 (±35) min, compared to 6 (±11) min in the group without POD (p < 0.001). In a subcohort with pre-bypass baseline MCAV (MCAV bas ) below the median MCAV bas of the whole cohort, prevalence of POD was 17% when MCAV rel during CPB was kept below 100%, but increased to 53% when these patients actually experienced relative cerebral hyperperfusion., Conclusions: Our results suggest a critical role for cerebral hyperperfusion in the pathogenesis of POD following on-pump open-heart surgery, recommending a more individualized hemodynamic management, especially in the population at risk.

Background: Post-operative delirium (POD) is a common post-operative complication in elderly individuals and imposes a significant health and financial burden. Identifying predictive biomarkers may help understand the pathophysiology of POD. Our objective is to summarize the evidence of pre-operative biomarkers and imaging tests to predict POD in patients undergoing non-cardiac surgery., Methods: A systematic search of English language articles in MEDLINE, EMBASE, Cochrane Database, PsychINFO, PubMed and ClinicalTrials. Gov up to January 2018 was performed. Studies that used biomarkers or imaging tests to predict POD and a validated POD assessment tool were included. Animal studies, paediatric, cardiac and intracranial surgery were excluded. Risk of bias was assessed using the Quality In Prognosis Study tool., Results: Thirty-four prospective cohort studies involving 4424 patients were included. Nineteen studies described serum tests [Interleukin-6, Insulin-like Growth Factor 1, C-Reactive Protein (CRP), cholinesterases, apolipoprotein-E genotype, leptin, hypovitaminosis, hypoalbuminaemia, gamma-amino butyric acid], 10 described cerebral-spinal fluid tests (monoamine precursor, melatonin, acute phase proteins, S100B and neurofibrillary tangles), and 5 described imaging tests. Two studies had high risk of bias due to unclear outcome measurement and study participation. CRP was significantly associated with POD in 5 studies. Other biomarkers were either examined by only a single study or two or more studies with conflicting results., Conclusion: CRP is the most promising biomarker associated with POD. However, we are still in the early stages in identifying biomarkers and imaging tests that may further understanding of the pathophysiology of POD.

Purpose of Review: Central pulse pressure (PP), a marker of vascular stiffness, is a novel indicator of risk for perioperative morbidity including ischemic stroke. Appreciation for the mechanism by which vascular stiffness leads to organ dysfunction along with understanding its clinical detection may lead to improved patient management., Recent Findings: Vascular stiffness is associated with increased mortality and neurologic, cardiac, and renal injury in nonsurgical and surgical patients. Left ventricular hypertrophy and diastolic dysfunction along with microcirculatory changes in the low vascular resistance, high blood flow, cerebral and renal vasculature are seen in patients with vascular stiffness. Pulse wave velocity and the augmentation index have higher sensitivity for detecting of vascular stiffness than peripheral PP as the hemodynamic consequences of vascular stiffness are secondary to alterations in the central vasculature. Vascular stiffness alters cerebral autoregulation, resulting in a high likelihood of having a lower limit of autoregulation more than 65 mmHg during surgery. Vascular stiffness may predispose to cerebral hypoperfusion, increasing vulnerability to ischemic stroke, postoperative delirium, and acute kidney injury., Summary: Vascular stiffness leads to alterations in cerebral, cardiac, and renal hemodynamics increasing the risk of perioperative ischemic stroke and neurologic, cardiac, and renal dysfunction.

This aim of this prospective observational cohort study was to evaluate any association between postoperatively impaired cerebrovascular autoregulation and the onset of delirium following cardiac surgery. Previous studies have shown that impaired intra-operative cerebrovascular autoregulation during cardiopulmonary bypass is associated with delirium. However, postoperative changes in cerebrovascular autoregulation and its association with delirium have not been investigated. One-hundred and eight consecutive adult cardiac surgical patients without baseline cognitive dysfunction or aphasia were included in the study. Cerebrovascular autoregulation was assessed by the Pearson correlation between near-infrared spectroscopy-derived cerebral tissue oxygen saturation and mean arterial pressure to derive the tissue oximetry index. Cerebrovascular autoregulation was monitored for a minimum of 90 min on postoperative day 0 and postoperative day 1. Delirium was assessed throughout intensive care unit admission using the confusion assessment method for the intensive care unit. We observed delirium in 24 of the 108 patients studied. The mean (SD) tissue oximetry index was higher in delirious patients on postoperative day 0 compared with non-delirious patients; 0.270 (0.199) vs. 0.180 (0.142), p = 0.044, but not on postoperative day 1; 0.130 (0.160) vs. 0.150 (0.130), p = 0.543. All patients showed improvement in tissue oximetry index on postoperative day 1 compared with postoperative day 0. Logistic regression analysis demonstrated tissue oximetry index on postoperative day 0 to be independently associated with delirium; odds ratio 1.05 (95%CI 1.01-1.10), p = 0.043. In conclusion, we found an association between impaired cerebrovascular autoregulation, measured by near-infrared spectroscopy, and delirium in the early postoperative period., (© 2018 Association of Anaesthetists.)

Background: Epileptiform discharges frequently occur in children during induction of anaesthesia. However, studies analysing the impact of epileptiform discharges on postoperative emergence delirium in children are still scarce. The aim of this study is to correlate the incidence of epileptiform activity during anaesthesia induction with the occurrence of emergence delirium during stay in the recovery room., Objectives: Prospective, observational cohort study in children 0.5 to 8 years old undergoing planned surgery. Bifrontal electroencephalogram electrodes were placed before induction of anaesthesia. Visual electroencephalogram analysis was performed from start of anaesthetic agent administration until intubation with regard to epileptiform patterns: rhythmic polyspikes; periodic epileptiform discharges; delta with spikes; and suppression with spikes. Emergence delirium was assessed during stay in the recovery room using the Pediatric Assessment of Emergence Delirium Score., Design: Prospective, observational cohort study., Setting: University hospital - Germany/Berlin. Children were included between September 2015 and February 2017., Patients: A total of 62 Children, aged 0.5 to 8 years old undergoing planned surgery were included., Main Outcome Measures: Primary outcome was emergence delirium. Secondary outcomes, peri-operative Electroencephalography (EEG) data analysis. The presented study analysed an association between emergence delirium and the occurrence of epileptiform discharges during anaesthesia induction., Results: A total of 43.5% of the children developed emergence delirium and 56.5% did not. Epileptiform discharges were observed more often in children developing emergence delirium (63%) compared with children not developing emergence delirium (43%). But only the occurrence of interictal spike events - such as rhythmic polyspikes; periodic epileptiform discharges and delta with spikes - were significantly related to emergence delirium (emergence delirium-group 48% vs. nonemergence delirium-group 14%, OR = 5.6 [95% CI: 1.7 to 18.7]; P = 0.004)., Conclusion: Emergence delirium in children is significantly related to interictal spike events occurring during induction of anaesthesia., Clinical Trial: NCT02481999.

What We Already Know About This Topic: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Postoperative delirium complicates approximately 15 to 20% of major operations in patients at least 65 yr old and is associated with adverse outcomes and increased resource utilization. Furthermore, patients with postoperative delirium might also be at risk of developing long-term postoperative cognitive dysfunction. One potentially modifiable variable is use of intraoperative processed electroencephalogram to guide anesthesia. This systematic review and meta-analysis examines the relationship between processed electroencephalogram monitoring and postoperative delirium and cognitive dysfunction., Methods: A systematic search for randomized controlled trials was conducted using Ovid MEDLINE, PubMed, EMBASE, Cochrane Library, and Google search using the keywords processed electroencephalogram, Bispectral Index, postoperative delirium, postoperative cognitive dysfunction. Screening and data extraction were conducted by two independent reviewers, and risk of bias was assessed. Postoperative delirium combined-effect estimates calculated with a fixed-effects model were expressed as odds ratios with 95% CIs., Results: Thirteen of 369 search results met inclusion criteria. Postoperative cognitive dysfunction data were excluded in meta-analysis because of heterogeneity of outcome measurements; results were discussed descriptively. Five studies were included in the quantitative postoperative delirium analysis, with data pooled from 2,654 patients. The risk of bias was low in three studies and unclear for the other two. The use of processed electroencephalogram-guided anesthesia was associated with a 38% reduction in odds for developing postoperative delirium (odds ratio = 0.62; P < 0.001; 95% CI, 0.51 to 0.76)., Conclusions: Processed electroencephalogram-guided anesthesia was associated with a decrease in postoperative delirium. The mechanism explaining this association, however, is yet to be determined. The data are insufficient to assess the relationship between processed electroencephalogram monitoring and postoperative cognitive dysfunction.

Background: Emergence delirium (ED) is an acute change in cognition after general anesthesia (GA) occurring in operative room, recovery room or in postanesthesia care. The automated propofol-remifentanil titration by Bispectral Index (BIS) (AutoTIVA) avoids period of deep (BIS<40) anesthesia and could potentially decrease the ED. The aim of this study was to evaluate ED in surgical patients under AutoTIVA, manual titration of propofol-remifentanil (ManualTIVA) or volatile BIS-guided GA. Moreover, we aimed to evaluate age-related postoperative Mini-Mental State Examination (MMSE) changes., Methods: One hundred and thirty-two adult patients scheduled for elective urologic surgery were randomized in: AutoTIVA, desflurane (DES), sevoflurane (SEVO), ManualTIVA anesthesia. The MMSE was performed before GA and 15 minutes after tracheal extubation., Results: The percentage of BIS 40-60 was significantly higher in the AutoTIVA compared to DES, SEVO and ManualTIVA (87% vs. 78 %, 58%, 39%, respectively; P≤0.001). The percentage of BIS<40 was significantly lower in AutoTIVA than in the other groups (P<0.001). No difference in hemodynamics was found among groups. Postoperative MMSE scores were similar to baseline in the AutoTIVA (26 [24-28] vs. 26 [23-28]) while they markedly decreased in all other groups (P<0.001). Postoperative MMSE decreased at any age. None experienced awareness was recorded., Conclusions: Our results suggest that patients treated with AutoTIVA performed better in the cognitive test compared to the other groups receiving manual target-controlled GA due to a higher adequate level of anesthesia measured by BIS. Cognitive tests should be performed to test ED in all patients undergoing GA.

Objective: To investigate the influence of analgesic-based midazolam sedation on delirium and outcomes in critically ill patients and to analyze the risk factors of delirium., Design: Single center, prospective randomized controlled trial., Setting: A surgical intensive care unit (ICU) in a tertiary care hospital in China., Patients: Mechanically ventilated patients requiring sedation., Measurements and Main Results: Patients admitted to the surgical intensive care unit who required sedation and were undergoing mechanical ventilation for longer than 24 hours were randomly divided into three groups: 1) the remifentanil group received remifentanil and midazolam, 2) the fentanyl group received fentanyl and midazolam, and 3) the control group received only midazolam. The analgesic effect, sedation depth, and presence of delirium were evaluated. To compare the effect of different therapies on the occurrence of delirium, days of mechanical ventilation, length of the ICU stay, and 28-day mortality were measured along with the risk factors for delirium. A total of 105 patients were enrolled, and 35 patients were included in each group. Compared to the control group, patients who received remifentanil and fentanyl required less midazolam each day (P = 0.038 and <0.001, respectively). Remifentanil has a significant effect on reducing the occurrence of delirium (P = 0.007). The logistic regression analysis of delirium demonstrated that remifentanil (OR 0.230, 95%Cl 0.074-0.711, P = 0.011) is independent protective factors for delirium, and high APACHE II score (OR 1.103, 95%Cl 1.007-1.208, P = 0.036) is the independent risk factor for delirium., Conclusion: Remifentanil and fentanyl can reduce the amount of midazolam required, and remifentanil could further reduce the occurrence of delirium.

We report the case of a 37-year-old female patient who required 22 surgeries following a pedestrian versus car accident. She was enrolled in a clinical study investigating emergence from anesthesia. In 10 of her 22 surgeries, we assessed her cognitive status in the postanesthesia care unit (PACU) using the Confusion Assessment Method. We observed PACU delirium in all 4 cases in which the patient received sevoflurane, but only in 1 of 6 cases in which she received propofol. The patient showed EEG α-band activity similar to that of an elderly patient who may reflect a greater risk of PACU delirium.

Objective: To gain insight in the underlying mechanism of reduced levels of consciousness due to hypoactive delirium versus recovery from anesthesia, we studied functional connectivity and network topology using electroencephalography (EEG)., Methods: EEG recordings were performed in age and sex-matched patients with hypoactive delirium (n=18), patients recovering from anesthesia (n=20), and non-delirious control patients (n=20), all after cardiac surgery. Functional and directed connectivity were studied with phase lag index and directed phase transfer entropy. Network topology was characterized using the minimum spanning tree (MST). A random forest classifier was calculated based on all measures to obtain discriminative ability between the three groups., Results: Non-delirious control subjects showed a back-to-front information flow, which was lost during hypoactive delirium (p=0.01) and recovery from anesthesia (p<0.01). The recovery from anesthesia group had more integrated network in the delta band compared to non-delirious controls. In contrast, hypoactive delirium showed a less integrated network in the alpha band. High accuracy for discrimination between hypoactive delirious patients and controls (86%) and recovery from anesthesia and controls (95%) were found. Accuracy for discrimination between hypoactive delirium and recovery from anesthesia was 73%., Conclusion: Loss of functional and directed connectivity were observed in both hypoactive delirium and recovery from anesthesia, which might be related to the reduced level of consciousness in both states. These states could be distinguished in topology, which was a less integrated network during hypoactive delirium., Significance: Functional and directed connectivity are similarly disturbed during a reduced level of consciousness due to hypoactive delirium and sedatives, however topology was differently affected., (Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

There remain unanswered questions and implications related to emergence delirium in children. Although we know that there are some predisposing factors to emergence delirium, we still are unable to predict accurately those who are at greatest risk. Emergence delirium should be considered as a ‘vital sign’, which should be followed and documented in every child in the postanaesthesia recovery period. Standardized screening tools should be adopted for paediatric emergence delirium.

Evidence regarding nursing support for delirium prevention is currently insufficient. An evaluation of changes in autonomic nervous activity over time after surgery would elucidate the features of autonomic nervous activity in patients with delirium. These results could provide a basis for effective nursing intervention and timing for preventing the onset of delirium. Here, we aimed to obtain basic data on effective nursing interventions for preventing the onset of postoperative delirium. Heart rate variability was recorded during the morning and nighttime on the day before surgery until 3 days postoperatively in elderly patients who underwent orthopedic surgery to investigate the manner in which heart rate and autonomic nervous activity changed over time. Data were collected over 11 months from July 2013 to November 2014. Surgical stress led to the maintenance of heart rate at a significantly higher value from the day of the surgery until postoperative day 3 compared to that before surgery. Moreover, the autonomic nervous activity remained unchanged during the morning, and it was significantly lower during the night from postoperative day 1 until postoperative day 3 than before the surgery. These results suggest that there is a decrease in parasympathetic nervous activity during the nighttime postoperatively.

Purpose of Review: The aim of this study was to review current literature on identification of patients at risk for postoperative delirium (POD) and to summarize recent findings on prophylaxis and treatment., Recent Findings: Age and preoperative cognitive impairment are among the most important risk factors of POD. POD is the result of a complex interplay of predisposing and precipitating factors. Thus, both prophylaxis and treatment require multicomponent intervention programs. No single medication to prevent or treat POD is available. Avoiding too deep anesthesia, avoiding additional psychoactive substances including benzodiazepines and intravenous opioids, and effective pain management as well as early mobilization are essential., Summary: An increase of the proportion of elderly patients undergoing surgery will lead to a higher incidence of POD. Preoperative assessment should facilitate identification of patients at high risk. Perioperative management should include monitoring depth of anesthesia, preference for nonopioid pain therapy, early regular delirium monitoring starting in the recovery room, avoiding ICU-sedation, early mobilization and exercise, and cognitive training.

Postoperative delirium is a common complication that often results in poor outcomes in surgical and elderly patients. Accumulating evidences suggest that the pathophysiology of delirium results from multiple neurotransmitter system dysfunctions. To further clarify the effects of the selective serotonin (5-HT) (1A) antagonist WAY-100635 on the behaviors in scopolamine induced-delirium rats and to explore the molecular mechanism, in this study, we investigated the change of monoamine levels in the cerebrospinal fluid (CSF) and different brain regions using high-performance liquid chromatography and assessed the behavioral retrieval of delirium rats treated with WAY-100635. It was found that 5-hydroxy-3-indoleacetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid, and homovanillic acid concentrations in the CSF of scopolamine-induced delirium rats were significantly increased, among which 5-HIAA was also increased in hippocampus and basolateral amygdala (BLA), and 5-HT(1A) receptor was significantly higher in the hippocampuses and BLA than other brain regions. Furthermore, intrahippocampus and intra-BLA stereotactic injection of WAY-100635 improved the delirium-like behavior of rats. Mechanistically, after WAY-100635 treatment, significant reduction of IL-1β release into CSF and NOD-like receptor family, pyrin domain containing 3 (NLRP3) expression, phosphorylated phosphatidylinositol-3-kinase (PI3K), protein kinase B (AKT), and S6K was observed. Altogether, these results suggest that delirium rats induced by scopolamine may be correlated with an increased cerebral concentration of 5-HT and dopamine neurotransmitters system; the selective 5-HT(1A) antagoniszts can reverse the delirium symptoms at some extent through tendering PI3K/Akt/mammalian target of rapamycin complex 1 (mTOR) activation-induced NLRP3 activity and then reducing IL-1β release., (© 2016 International Union of Biochemistry and Molecular Biology.)

Objective: To explore the risk factors associated with postoperative delirium (PD) in elderly patients following total hip arthroplasty (THA) for hip fracture., Methods: This prospective study enrolled elderly patients (≥ 65 years) with hip fractures who underwent THA under general anaesthesia, and who had a complete set of postoperative observations. Detailed medical history and perioperative characteristics were recorded. During the postoperative period, patients were assessed twice daily for PD using the Confusion Assessment Method., Results: A total of 572 patients were eligible for inclusion in the study. Of these, 120 patients (21.0%) were diagnosed with PD and 452 patients (79.0%) did not experience PD. Multivariate stepwise logistic regression analyses showed that older age, a history of stroke, lower albumin, higher blood glucose, higher total bilirubin, higher C-reactive protein, longer surgery duration and higher volume of red blood cell transfusions were independent risk factors for PD., Conclusions: Correcting the modifiable risk factors might help prevent PD. Strategies might include nutritional support, tight blood glucose control, improvement of liver function, preoperative infection control and minimizing surgical injury or blood loss., (© The Author(s) 2016.)

Objective: A prospective, double-blind, randomized controlled trial to compare the effect of preoperative midazolam or ketamine on the incidence of emergence agitation (EA) following sevoflurane anaesthesia in children., Methods: Paediatric patients (2-6 years old) undergoing ophthalmic surgery were allocated to receive premedication with either 0.1 mg/kg midazolam or 1 mg/kg ketamine. Incidence of EA and postoperative pain scores were recorded at 10-min intervals in the postanaesthetic care unit (PACU). The use of EA rescue medications (fentanyl or midazolam) was recorded., Results: The incidence of EA was significantly lower in the ketamine group (n = 33) than the midazolam group (n = 34) at 10 and 20 min after transfer to PACU. There was no significant difference in overall incidence of EA. The frequency of midazolam use as rescue medication was significantly lower in the katamine group than in the midazolam group., Conclusion: Premedication with ketamine is more effective than midazolam in preventing EA during the early emergence period after sevoflurane anaesthesia in children., (© The Author(s) 2016.)