Postoperative delirium in oral and maxillofacial surgery: a scoping review.

BACKGROUND: Postoperative delirium (POD) in the oral and maxillofacial settings has gained more attention in recent decades. Due to advances in medical technology, treatment possibilities have expanded treatment for elderly and frail patients. This scoping review explores the correlation between POD and oral and maxillofacial surgery, summarizing screening and management protocols and identifying risk factors in this surgical field. METHODS: This review follows the Scoping Review extension of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA-ScR). A comprehensive literature search was performed using multiple databases, focusing on articles published from 2002 to 2023 that discuss delirium in oral and maxillofacial surgery settings. The review was registered beforehand in the Open Science Framework ( https://osf.io/r2ebc ). RESULTS: From the initial 644 articles, 68 met the inclusion criteria. These studies highlighted the significant heterogeneity in POD diagnosis methods. The review identifies multiple risk factors across the preoperative, intraoperative, and postoperative phases that influence the occurrence of POD. Significant and independent risk factors in multiple regression analysis were highlighted, creating a clinical prediction list for the occurrence of POD. CONCLUSION: It is crucial to preoperatively identify patients at risk for POD and actively modify these risks throughout the patient's hospital stay. Implementing nonpharmacological preventive measures for at-risk patients is recommended to decrease the incidence of POD. Future research should focus on creating standardized specialty-specific protocols incorporating validated assessment tools and addressing the full spectrum of risk factors associated with POD.

Incidence of emergence delirium after homeostasis-guided pediatric anesthesia for ear-nose-throat surgery.

BACKGROUND: Emergence delirium is a complication of pediatric anesthesia during the early recovery period. Children undergoing ear, nose, and throat surgery are at high risk. The Pediatric Assessment of Emergence Delirium (PAED) scale is used for diagnosis and founded to specify the degree of emergence delirium. However, there is no consensus regarding a threshold value for emergence delirium diagnosis. Homeostasis-guided pediatric general anesthesia aims to maintain physiological parameters within normal ranges. In this prospective, observational study we evaluated the incidence of emergence delirium in children undergoing elective ear, nose, and throat surgery under standardized homeostasis-guided general anesthesia. Secondarily, we identified risk factors associated with an increased PAED score. METHODS: In children aged 0-6 years, we collected data from standard monitoring, depth of anesthesia, and preoperative glucose and ketone body levels. These variables were studied as risk or protective factors for increased PAED >0 scores using multivariate logistic regression. RESULTS: Of the 105 children analyzed, only five children (4.7%) had emergence delirium according to a threshold PAED score ≥10, while 37 children (35%) had PAED scores >0. Statistical analysis of the PAED outcome identified two significant positive associations with pain (P<0.001) and preoperative blood glucose levels (P=0.006) and one negative association with preoperative ketone body levels (P<0.001). CONCLUSIONS: Our cohort observed a lower incidence of emergence delirium than in the literature. Higher pain intensity and lower blood glucose levels were risk factors for PAED > 0, whereas preoperative ketone body levels were protective.

Effect of different anesthetic modalities on postoperative delirium in elderly hip fractures: A meta-analysis.

BACKGROUND: Previous findings on the effect of general versus spinal anesthesia on postoperative delirium in elderly people with hip fractures are somewhat controversial. This article included the latest randomized controlled study for meta-analysis to evaluate the effect of general anesthesia (GA) and spinal anesthesia (SA) on delirium after hip fracture surgery in the elderly, so as to guide the clinical. METHODS: Cochrane Library, PubMed, Web Of Science, and Embase were searched from inception up to January 16, 2024. Randomized controlled trial (RCT) was included to evaluate the postoperative results of GA and SA in elderly patients (≥50 years old) undergoing hip fracture surgery. Two researchers independently screened for inclusion in the study and extracted data. Heterogeneity was assessed by the I²and Chi-square tests, and P < .1 or I² ≥ 50% indicated marked heterogeneity among studies. The Mantel-Haenszel method was used to estimate the combined relative risk ratio (RR) and the corresponding 95% confidence interval (CI) for the binary variables. RESULTS: Nine randomized controlled trials were included. There was no significant difference (RR = 0.93, 95% CI = 0.774-1.111, P > .05) in the incidence of postoperative delirium between the GA group and the SA group. In intraoperative blood transfusion (RR = 1.0, 95% CI = 0.77-1.28, Z = 0.04, P = .971), pulmonary embolism (RR = 0.795, 95% CI = 0.332-1.904, Z = 0.59, P = .606), pneumonia (RR = 1.47, 95% CI = 0.75-2.87, P = .675), myocardial infarction (RR = 0.97, 95% CI = 0.24-3.86, Z = 0.05, P = .961), heart failure (RR = 0.80, 95% CI = 0.26-2.42, Z = 0.40, P = .961), urinary retention (RR = 1.42, 95% CI = 0.77-2.61, Z = 1.11, P = .267) were similar between the 2 anesthetic techniques. CONCLUSION: There is no significant difference in the effect of GA and SA on postoperative delirium in elderly patients with hip fracture, and their effects on postoperative complications are similar.

Effect of Dexmedetomidine Combined with Remifentanil on Emergence Agitation During Awakening from Sevoflurane Anesthesia for Pediatric Liver Surgery.

BACKGROUND We aimed to assess the effect of dexmedetomidine (Dex) combined with remifentanil on emergence agitation (EA) during awakening from sevoflurane anesthesia for pediatric liver surgery. MATERIAL AND METHODS Sixty children who underwent liver surgery in our hospital were prospectively selected and randomly allocated into group A (placebo+remifentanil+sevoflurane) or group B (Dex+remifentanil+sevoflurane). Mean arterial pressure (MAP) and heart rate (HR) at different time points, agitation score during awakening, behavioral status, pain level, and the incidence of postoperative adverse effects were compared in both groups. RESULTS Children in group B had lower HR and MAP levels immediately after tracheal extubation and 5 min after tracheal extubation than those in group A. The Aono's scores, PAED agitation scores, and CHIPP scores at 15 min and 30 min of admission to the PACU were lower in group B than in group A. The incidence of agitation during postoperative anesthesia awakening was lower in group B in contrast to group A. There was no significant difference in postoperative adverse reactions between group A and group B. CONCLUSIONS In pediatric liver surgery, the use of Dex+remifentanil+sevoflurane anesthesia can reduce the incidence of EA during the awakening period, stabilize hemodynamic levels, and relieve postoperative pain, and has fewer postoperative adverse effects, which warrants clinical application.

The effect of magnesium sulfate on emergence agitation in surgical adult patients undergoing general anesthesia: A systematic review and meta-analysis of randomized controlled trials.

STUDY OBJECTIVE: Investigating the effect of magnesium sulfate (MS) on emergence agitation (EA) in adult surgical patients following general anesthesia (GA). DESIGN: Systematic literature review and meta-analysis (PROSPERO number: CRD42023461988). SETTING: Review of published literature. PATIENTS: Adults undergoing GA. INTERVENTIONS: Intravenous administration of MS. MEASUREMENTS: We searched PubMed/MEDLINE, EMBASE, the Cochrane Library, Scopus, and Web of Science for publications until September 14, 2023. The primary outcome was the incidence of EA, while the secondary outcomes included the impact of MS on postoperative agitation score (PAS), emergence variables and adverse events. Relative risk (RR) with 95% confidence interval (CI) measured dichotomous outcome, while standardized mean difference (SMD) or mean difference (MD) with 95% CI measured continuous outcomes. MAIN RESULTS: Meta-analysis of five randomized controlled trials (RCTs) indicated that MS was associated with a lower incidence of EA at various time points (0 min: RR = 0.62, 95% CI [0.41, 0.95]; p = 0.183, I2 = 43.6%; 5 min: RR = 0.29, 95% CI [0.16, 0.52]; p = 0.211, I2 = 36%; 10 min: RR = 0.14, 95% CI [0.06, 0.32]; p = 0.449, I2 = 0%; 15 min: RR = 0.11, 95% CI [0.02, 0.55]; p = 0.265, I2 = 19.5%; 30 min: RR = 0.05, 95% CI [0.00, 0.91]; the postoperative period: RR = 0.21, 95% CI [0.09, 0.49]; p = 0.724, I2 = 0%;). Additionally, MS was associated with a reduced PAS at various time points except for 0 min. However, no significant differences were observed in extubation time, the length of stay in the post-anesthesia care unit, postoperative nausea and vomiting or total complications. CONCLUSIONS: Limited available evidence suggests that MS was associated with a lower incidence of EA. Nevertheless, further high-quality studies are warranted to strengthen and validate the effect of MS in preventing EA in adult surgical patients.

The effect of deep and awake extubation on emergence agitation after nasal surgery: a randomized controlled trial.

BACKGROUND: Post-anesthetic emergence agitation is common after general anesthesia and may cause adverse consequences, such as injury as well as respiratory and circulatory complications. Emergence agitation after general anesthesia occurs more frequently in nasal surgery than in other surgical procedures. This study aimed to assess the occurrence of emergence agitation in patients undergoing nasal surgery who were extubated under deep anesthesia or when fully awake. METHODS: A total of 202 patients (18-60 years, American Society of Anesthesiologists classification: I-II) undergoing nasal surgery under general anesthesia were randomized 1:1 into two groups: a deep extubation group (group D) and an awake extubation group (group A). The primary outcome was the incidence of emergence agitation. The secondary outcomes included number of emergence agitations, sedation score, vital signs, and incidence of adverse events. RESULTS: The incidence of emergence agitation was lower in group D than in group A (34.7% vs. 72.8%; p < 0.001). Compared to group A, patients in group D had lower Richmond Agitation-Sedation Scale scores, higher Ramsay sedation scores, fewer agitation episodes, and lower mean arterial pressure when extubated and 30 min after surgery, whereas these indicators did not differ 90 min after surgery. There was no difference in the incidence of adverse events between the two groups. CONCLUSIONS: Extubation under deep anesthesia can significantly reduce emergence agitation after nasal surgery under general anesthesia without increasing the incidence of adverse events. TRIAL REGISTRATION: Registered in Clinicaltrials.gov (NCT04844333) on 14/04/2021.

Postoperative Delirium and the Older Adult: Untangling the Confusion.

Postoperative delirium is one of the most prevalent postoperative complications, affecting mostly older adults. Its incidence is expected to rise because of surgical advances, shifting demographics, and increased life expectancy. Although an acute alteration in brain function, postoperative delirium is associated with adverse outcomes, including progressive cognitive decline and dementia, that place significant burdens on patients' lives and healthcare systems. This has prompted efforts to understand the mechanisms of postoperative delirium to provide effective prevention and treatment. There are multiple mechanisms involved in the etiology of postoperative delirium that share similarities with the physiological changes associated with the aging brain. In addition, older patients often have multiple comorbidities including increased cognitive impairment that is also implicated in the genesis of delirium. These tangled connections pinpointed a shift toward creation of a holistic model of the pathophysiology of postoperative delirium. Scientific advancements integrating clinical risk factors, possible postoperative delirium biomarkers, genetic features, digital platforms, and other biotechnical and information technological innovations, will become available in the near future. Advances in artificial intelligence, for example, will aggregate cognitive testing platforms with patient-specific postoperative delirium risk stratification studies, panels of serum and cerebrospinal fluid molecules, electroencephalogram signatures, and gut microbiome features, along with the integration of novel polygenetic variants of sleep and cognition. These advances will allow for the enrollment of high-risk patients into prevention programs and help uncover new pharmacologic targets.

Scoring systems, expert assessment, and identification of risk factors for the emergence of delirium in paediatric patients: Prospective cohort study.

INTRODUCTION: Emergence delirium (ED) is a transient irritative and dissociative state that arises after the cessation of anaesthesia in patients who do not respond to calming measures. There are many risk factors for ED, but the exact cause and underlying mechanism have not been determined because the definition of ED is still unclear in consensus. This study aims to determine ED incidence, identify ED risk factors and external validation of Watcha, Cravero and expert assessment to Pediatric Anesthesia Emergence Delirium (PAED) scoring system in ED prediction. MATERIALS AND METHODS: This study is a prospective cohort study on 79 paediatrics who underwent elective surgery with general anaesthesia. Parameter measures include the incidence of ED, ED risk factors, and the relationship between PAED, Watcha, Cravero score and expert assessment. The ED risk factor was analysed using univariate and multivariate analysis. The relationship between PAED, Watcha, Cravero score, and expert assessment was determined using Receiver Operating Characteristic (ROC) curve analysis. RESULTS: The incidence of ED was 22.8%. All parameters examined in this study showed p < 0.05. Watcha's scoring correlates with the PAED scoring and shows the highest discrimination ability with AUC 0.741 and p < 0.05. CONCLUSION: The incidence of ED in paediatrics is relatively high. Compared to others, Watcha score are more reliable for ED prediction. However, some demographic and perioperative factors are not the risk factor of ED.

Risk factors for postoperative delirium in elderly patients undergoing heart valve surgery with cardiopulmonary bypass.

BACKGROUND: The aim of this study was to identify the risk factors for postoperative delirium (POD) in elderly patients undergoing heart valve surgery with cardiopulmonary bypass (CPB). METHODS: Elderly patients undergoing elective heart valve surgery with CPB in The First Affiliated Hospital of Wenzhou Medical University between March 2022 and March 2023 were selected for this investigation. They were divided into a POD group and a non-POD group. Their baseline information was collected and recorded, and the patients were subjected to neurocognitive function assessment using the Mini-Mental State Examination and the Montreal Cognitive Assessment scales before surgery. We also recorded their intraoperative indicators such as duration of surgery, duration of CPB, duration of aortic cross-clamp, blood transfusion, and postoperative indicators such as duration of mechanical ventilation, postoperative 24-hour drainage volume, and pain score. Regional cerebral oxygen saturation was monitored intraoperatively by near-infrared spectroscopy based INVOS5100C Regional Oximeter. Patients were assessed for the occurrence of POD using Confusion Assessment Method for the Intensive Care Unit, and logistic regression analysis of risk factors for POD was performed. RESULTS: The study finally included 132 patients, with 47 patients in the POD group and 85 ones in the non-POD group. There were no significant differences in baseline information and preoperative indicators between the two groups. However, marked differences were identified in duration of surgery, duration of CPB, duration of aortic cross-clamp, duration of postoperative mechanical ventilation, postoperative length of stay in cardiac intensive care unit, postoperative length of hospital stay, intraoperative blood transfusion, postoperative pain score, and postoperative 24-hour drainage volume between the two groups (p < 0.05). Additionally, the two groups had significant differences in rScO2 at each intraoperative time point and in the difference of rScO2 from baseline at each intraoperative time point (p < 0.05). Multivariate logistic regression analysis showed that duration of surgery > 285 min (OR, 1.021 [95% CI, 1.008-1.035]; p = 0.002), duration of postoperative mechanical ventilation > 23.5 h (OR, 6.210 [95% CI, 1.619-23.815]; p = 0.008), and postoperative CCU stay > 3.5 d (OR, 3.927 [95% CI, 1.046-14.735]; p = 0.043) were independent risk factors of the occurrence of POD while change of rScO2 at T1>50.5 (OR, 0.832 [95% CI 0.736-0.941]; p = 0.003) was a protective factor for POD. CONCLUSION: Duration of surgery duration of postoperative mechanical ventilation and postoperative CCU stay are risk factors for POD while change of rScO2 at T1 is a protective factor for POD in elderly patients undergoing heart valve surgery with CPB.

The Association of Preoperative Diabetes With Postoperative Delirium in Older Patients Undergoing Major Orthopedic Surgery: A Prospective Matched Cohort Study.

BACKGROUND: Postoperative delirium (POD) is a common form of postoperative brain dysfunction, especially in the elderly. However, its risk factors remain largely to be determined. This study aimed to investigate whether (1) preoperative diabetes is associated with POD after elective orthopedic surgery and (2) intraoperative frontal alpha power is a mediator of the association between preoperative diabetes and POD. METHODS: This was a prospective matched cohort study of patients aged 60 years or more, with a preoperative diabetes who underwent elective orthopedic surgery. Nondiabetic patients were matched 1:1 to diabetic patients in terms of age, sex, and type of surgery. Primary outcome was occurrence of POD, assessed using the 3-minute Diagnostic Confusion Assessment Method (3D-CAM) once daily from 6 pm to 8 pm during the postoperative days 1-7 or until discharge. Secondary outcome was the severity of POD which was assessed for all participants using the short form of the CAM-Severity. Frontal electroencephalogram (EEG) was recorded starting before induction of anesthesia and lasting until discharge from the operating room. Intraoperative alpha power was calculated using multitaper spectral analyses. Mediation analysis was used to estimate the proportion of the association between preoperative diabetes and POD that could be explained by intraoperative alpha power. RESULTS: A total of 138 pairs of eligible patients successfully matched 1:1. After enrollment, 6 patients in the diabetes group and 4 patients in the nondiabetes group were excluded due to unavailability of raw EEG data. The final analysis included 132 participants with preoperative diabetes and 134 participants without preoperative diabetes, with a median age of 68 years and 72.6% of patients were female. The incidence of POD was 16.7% (22/132) in patients with preoperative diabetes vs 6.0% (8/134) in patients without preoperative diabetes. Preoperative diabetes was associated with increased odds of POD after adjustment of age, sex, body mass index, education level, hypertension, arrhythmia, coronary heart disease, and history of stroke (odds ratio, 3.2; 95% confidence interval [CI], 1.4-8.0; P = .009). The intraoperative alpha power accounted for an estimated 20% (95% CI, 2.6-60%; P = .021) of the association between diabetes and POD. CONCLUSIONS: This study suggests that preoperative diabetes is associated with an increased risk of POD in older patients undergoing major orthopedic surgery, and that low intraoperative alpha power partially mediates such association.

Regional anaesthesia via parasternal catheters inserted preoperatively and postoperative delirium after cardiac surgery: A prospective unrandomised clinical trial.

VISUAL ABSTRACT: http://links.lww.com/EJA/A927.

Effect of three modalities on emergence agitation among post-traumatic stress disorder patients undergoing laparoscopy: a randomized controlled study.

BACKGROUND AND AIM: Emergence agitation (EA) after general anesthesia is common in patients with post-traumatic stress disorder (PTSD). Due to the recent worldwide events such as the Covid-19 pandemic and wars, PTSD is not rare. Accordingly, a reliable, cost-effective anesthetic protocol to lower the incidence of EA is crucial. Therefore, we aimed to compare three different interventions for avoiding EA in PTSD patients undergoing gynecological laparoscopic surgery. Participants were divided into four groups: 1: performing pre-operative relaxation techniques (deep breathing exercise and progressive muscle relaxation [PMR]); 2: administrating intra-operative Ketamine; 3: applying both previously mentioned strategies and 4 as controls. METHODS: This study was carried out on 144 adult women scheduled for gynecological laparoscopy, randomly allocated into four groups: three intervention groups and a control group (36 each). Women aged 18-45 years old, with a diagnosis of PTSD were included in the study. Patients with a positive history of major neurological, cardiovascular, metabolic, respiratory, or renal disease were excluded. Any patient who reported the use of psychiatric drugs were also excluded from the study. Data was analyzed using IBM SPSS Statistics software version 26. Kolmogorov- Smirnov was used to verify the normality of the distribution of variables. Odds ratio was calculated to clarify the strength and direction of the association between intervention groups and control. Data was deemed significant at a p-value ≤0.05. RESULTS: Heart rate (HR) and Mean Arterial Blood Pressure (MABP) intra-operative and post-operative till 24 hours were significantly lower in groups 1, 2, and 3 compared to group 4 (p<0.001). There was a significant statistical difference in the intraoperative HR percentage decrease. MABP percentage decrease post-operative was higher in all the intervention groups with no statistically significant difference, except for group 1 compared to group 4, which was statistically significant (12.28 ± 11.77 and 6.10 ± 7.24, p=0.025). Visual Analogue Scale measurements were significantly less in the intervention groups 1, 2, and 3 compared to group 4. On Riker sedation-agitation scores, group 1 was 85 times more likely to be non-agitated (85 (15.938 - 453.307), p<0.001), group 2 was 175 times more likely to be non-agitated (175 (19.932-1536.448), p<0.001) and group 3 was protected against agitation. CONCLUSION: Pre-operative relaxation techniques (breathing exercises and PMR) significantly lowered HR, MABP, VAS score, and EA than controls. These effects were not significantly different from intra-operative ketamine injection or the combination of both (relaxation techniques and ketamine). We recommend routine pre-operative screening for PTSD and the application of relaxation techniques (breathing exercises and PMR) in the pre-operative preparation protocol of PTSD-positive cases as well as routine practical application of preoperative relaxation techniques. Further studies on using pre-operative relaxation techniques in general could be cost-effective.

Association of preoperative neutrophil-lymphocyte ratios with the emergence delirium in pediatric patients after tonsillectomy and adenoidectomy: an observational prospective study.

PURPOSE: The study aimed to investigate potential risk factors for emergence delirium (ED) in pediatric patients after tonsillectomy and adenoidectomy (T&A). METHODS: This prospective, single-center observational study enrolled children aged 3-7 years who underwent T&A under general anesthesia. ED was assessed according to DSM-IV or V criteria. Receiver operating characteristic curve analysis was performed to evaluate the predicative and cut-off values of risk factors, including age, preoperative anxiety level, postoperative pain and neutrophil-lymphocyte ratio (NLR) for ED. Univariate and multivariate logistic regression analyses were performed to investigate risk factors for ED. RESULTS: 94 pediatric patients who underwent T&A were enrolled and 19 developed ED (an incidence of 25.3%). Receiver operating characteristic analysis indicated that preoperative NLR was a significant predictor of ED with a cut-off value of 0.8719 and an area under the curve (AUC) of 0.671 (95% confidence interval (CI) 0.546-0.796, P = 0.022). Preoperative NLR (< 0.8719) and postoperative pain were independent risk factors associated with ED (odds ratio: 0.168, 95% CI 0.033-0.858, P = 0.032; odds ratio: 7.298, 95% CI 1.563-34.083, P = 0.011) according to multivariate logistic regression analysis. CONCLUSIONS: Preoperative NLR level and postoperative pain were independent risk factors for ED in pediatric patients undergoing T&A.

Association of sleep quality on the night of operative day with postoperative delirium in elderly patients: A prospective cohort study.

BACKGROUND: Sleep disturbances in the peri-operative period have been associated with adverse outcomes, including postoperative delirium (POD). However, research on sleep quality during the immediate postoperative period is limited. OBJECTIVES: This study aimed to investigate the association between sleep quality on the night of the operative day assessed using the Sleep Quality Numeric Rating Scale (SQ-NRS), and the incidence of POD in a large cohort of surgical patients. DESIGN: A prospective cohort study. SETTING: A tertiary hospital in China. PATIENTS: This study enrolled patients aged 65 years or older undergoing elective surgery under general anaesthesia. The participants were categorised into the sleep disturbance and no sleep disturbance groups according to their operative night SQ-NRS. MAIN OUTCOME MEASURES: The primary outcome was delirium incidence, whereas the secondary outcomes included acute kidney injury, stroke, pulmonary infection, cardiovascular complications and all-cause mortality within 1 year postoperatively. RESULTS: In total, 3072 patients were included in the analysis of this study. Among them, 791 (25.72%) experienced sleep disturbances on the night of operative day. Patients in the sleep disturbance group had a significantly higher risk of developing POD (adjusted OR 1.43, 95% CI 1.11 to 1.82, P  = 0.005). Subgroup analysis revealed that age 65-75 years; male sex; ASA III and IV; haemoglobin more than 12 g l -1 ; intra-operative hypotension; surgical duration more than 120 min; and education 9 years or less were significantly associated with POD. No interaction was observed between the subgroups. No significant differences were observed in the secondary outcomes, such as acute kidney injury, stroke, pulmonary infection, cardiovascular complications and all-cause mortality within 1 year postoperatively. CONCLUSIONS: The poor subjective sleep quality on the night of operative day was independently associated with increased POD risk, especially in certain subpopulations. Optimising peri-operative sleep may reduce POD. Further research should investigate potential mechanisms and causal relationships. TRIAL REGISTRY: chictr.org.cn: ChiCTR1900028545.

Electroencephalogram Biomarkers from Anesthesia Induction to Identify Vulnerable Patients at Risk for Postoperative Delirium.

BACKGROUND: Postoperative delirium is a common complication in elderly patients undergoing anesthesia. Even though it is increasingly recognized as an important health issue, the early detection of patients at risk for postoperative delirium remains a challenge. This study aims to identify predictors of postoperative delirium by analyzing frontal electroencephalogram at propofol-induced loss of consciousness. METHODS: This prospective, observational single-center study included patients older than 70 yr undergoing general anesthesia for a planned surgery. Frontal electroencephalogram was recorded on the day before surgery (baseline) and during anesthesia induction (1, 2, and 15 min after loss of consciousness). Postoperative patients were screened for postoperative delirium twice daily for 5 days. Spectral analysis was performed using the multitaper method. The electroencephalogram spectrum was decomposed in periodic and aperiodic (correlates to asynchronous spectrum wide activity) components. The aperiodic component is characterized by its offset (y intercept) and exponent (the slope of the curve). Computed electroencephalogram parameters were compared between patients who developed postoperative delirium and those who did not. Significant electroencephalogram parameters were included in a binary logistic regression analysis to predict vulnerability for postoperative delirium. RESULTS: Of 151 patients, 50 (33%) developed postoperative delirium. At 1 min after loss of consciousness, postoperative delirium patients demonstrated decreased alpha (postoperative delirium: 0.3 µV2 [0.21 to 0.71], no postoperative delirium: 0.55 µV2 [0.36 to 0.74]; P = 0.019] and beta band power [postoperative delirium: 0.27 µV2 [0.12 to 0.38], no postoperative delirium: 0.38 µV2 [0.25 to 0.48]; P = 0.003) and lower spectral edge frequency (postoperative delirium: 10.45 Hz [5.65 to 15.04], no postoperative delirium: 14.56 Hz [9.51 to 16.65]; P = 0.01). At 15 min after loss of consciousness, postoperative delirium patients displayed a decreased aperiodic offset (postoperative delirium: 0.42 µV2 (0.11 to 0.69), no postoperative delirium: 0.62 µV2 [0.37 to 0.79]; P = 0.004). The logistic regression model predicting postoperative delirium vulnerability demonstrated an area under the curve of 0.73 (0.69 to 0.75). CONCLUSIONS: The findings suggest that electroencephalogram markers obtained during loss of consciousness at anesthesia induction may serve as electroencephalogram-based biomarkers to identify at an early time patients at risk of developing postoperative delirium.

Serum Neurofilament Light and Postoperative Delirium in Cardiac Surgery: A Preplanned Secondary Analysis of a Prospective Observational Study.

BACKGROUND: Impaired cognition is a major predisposing factor for postoperative delirium, but it is not systematically assessed. Anesthesia and surgery may cause postoperative delirium by affecting brain integrity. Neurofilament light in serum reflects axonal injury. Studies evaluating the perioperative course of neurofilament light in cardiac surgery have shown conflicting results. The authors hypothesized that postoperative serum neurofilament light values would be higher in delirious patients, and that baseline concentrations would be correlated with patients' cognitive status and would identify patients at risk of postoperative delirium. METHODS: This preplanned secondary analysis included 220 patients undergoing elective cardiac surgery with cardiopulmonary bypass. A preoperative cognitive z score was calculated after a neuropsychological evaluation. Quantification of serum neurofilament light was performed by the Simoa (Quanterix, USA) technique before anesthesia, 2 h after surgery, on postoperative days 1, 2, and 5. Postoperative delirium was assessed using the Confusion Assessment Method for Intensive Care Unit, the Confusion Assessment Method, and a chart review. RESULTS: A total of 65 of 220 (29.5%) patients developed postoperative delirium. Delirious patients were older (median [25th percentile, 75th percentile], 74 [64, 79] vs. 67 [59, 74] yr; P < 0.001) and had lower cognitive z scores (-0.52 ± 1.14 vs. 0.21 ± 0.84; P < 0.001). Postoperative neurofilament light concentrations increased in all patients up to day 5, but did not predict delirium when preoperative concentrations were considered. Baseline neurofilament light values were significantly higher in patients who experienced delirium. They were influenced by age, cognitive z score, renal function, and history of diabetes mellitus. Baselines values were significantly correlated with cognitive z scores (r, 0.49; P < 0.001) and were independently associated with delirium whenever the patient's cognitive status was not considered (hazard ratio, 3.34 [95% CI, 1.07 to 10.4]). CONCLUSIONS: Cardiac surgery is associated with axonal injury, because neurofilament light concentrations increased postoperatively in all patients. However, only baseline neurofilament light values predicted postoperative delirium. Baseline concentrations were correlated with poorer cognitive scores, and they independently predicted postoperative delirium whenever patient's cognitive status was undetermined.