Clinical Application of Different Doses of Hydromorphone Slow-Release Analgesia in Lumbar Fusion in Elderly Patients

INTRODUCTION

The aim of this study is to examine the analgesic efficacy of varying doses of hydromorphone hydrochloride in conjunction with absorbable gelatin sponge for postoperative pain management in elderly individuals undergoing lumbar fusion surgery. Additionally, the study aims to assess the sustained release analgesic properties of this combination and to determine the optimal dosage of hydromorphone hydrochloride for effective pain relief.

METHODS

A total of 113 elderly patients (aged ≥ 65 years old) meeting the criteria for 1-2-level posterior lumbar fusion surgery at Ganzhou City People's Hospital between July 2022 and August 2023 were randomly assigned to four groups: group A (0.2 mg hydromorphone hydrochloride 1 ml), group B (0.3 mg hydromorphone hydrochloride 1.5 ml), group C (0.4 mg hydromorphone hydrochloride 2 ml), and group D (0.9% normal saline 2 ml) for standard anesthesia induction and maintenance. Prior to suturing the incision, gelfoam was utilized to administer epidural analgesia to each group. Following the surgical procedure, an intravenous analgesia pump was utilized for pain management. The baseline infusion rate was set at 0.5 ml/h. Patient-controlled analgesia (PCA) was administered at a dose of 2 ml, with a lockout interval of 20 min, allowing the patient to self-administer as needed. Pain relief was assessed using the visual analogue scale (VAS) prior to surgery, as well as at 1 day and 3 days post-operation. The frequency of PCA requests within the initial 48-h postoperative period, the remedial analgesia with dezocine, postoperative adverse reactions, and duration of hospitalization were documented for analysis.

RESULTS

The VAS scores of groups B and C were found to be significantly lower than those of group D 1 day after the operation. Additionally, VAS scores at 3 days post-operation, remedial rate of dezocine and PCA follow-up times at 48 h in groups A, B, and C were significantly lower compared to group D (P < 0.001). There was no statistically significant difference between group B and group C in VAS scores at 1 day and 3 days post-operation, as well as PCA follow-up times at 48 h post-operation (P < 0.001). Furthermore, the VAS scores of groups B and C were lower than those of group A at 1 day and 3 days post-operation (P < 0.05). The PCA frequency of group C was also lower than that of group A at 48 h post-operation (P < 0.05).

CONCLUSION

The combination of hydromorphone hydrochloride and absorbable gelatin sponge epidural analgesia has been shown to enhance postoperative pain management. A dosage of 0.4 mg of hydromorphone hydrochloride may be considered an appropriate analgesic dose, as it can provide effective pain relief without eliciting adverse reactions.

TRIAL REGISTRATION

ChiCTR.org.cn(ChiCTR2200064863). Registered on October 20, 2022.

Postoperative cognitive dysfunction: a concept analysis

BACKGROUND

Post-operative cognitive dysfunction (POCD) is a concern for clinicians that often presents post-surgery where generalized anesthesia has been used. Its prevalence ranges from 36.6% in young adults to 42.4% in older individuals. Conceptual clarity for POCD is lacking in the currently body literature. Our two-fold purpose of this concept analysis was to (1) critically appraise the various definitions, while also providing the best definition, of POCD and (2) narratively synthesize the attributes, surrogate or related terms, antecedents (risk factors), and consequences of the concept.

METHOD

The reporting of our review was guided by the PRISMA statement and the 6-step evolutionary approach to concept analysis developed by Rodgers. Three databases, including Medline, CINAHL, and Web of Science, were searched to retrieve relevant literature on the concept of POCD. Two independent reviewers conducted abstract and full-text screening, data extraction, and appraisal. The review process yielded a final set of 86 eligible articles.

RESULT

POCD was defined with varying severities ranging from subtle-to-extensive cognitive changes (1) affecting single or multiple cognitive domains that manifest following major surgery (2), is transient and reversible, and (3) may last for several weeks to years. The consequences of POCD may include impaired quality of life, resulting from withdrawal from the labor force, increased patients' dependencies, cognitive decline, an elevated risk of dementia, rising healthcare costs, and eventual mortality.

CONCLUSION

This review resulted in a refined definition and comprehensive analysis of POCD that can be useful to both researchers and clinicians. Future research is needed to refine the operational definitions of POCD so that they better represent the defining attributes of the concept.

Cognitive and Cerebrospinal Fluid Alzheimer's Disease-related Biomarker Trajectories in Older Surgical Patients and Matched Nonsurgical Controls

BACKGROUND

Anesthesia and/or surgery accelerate Alzheimer's disease pathology and cause memory deficits in animal models, yet there is a lack of prospective data comparing cerebrospinal fluid (CSF) Alzheimer's disease-related biomarker and cognitive trajectories in older adults who underwent surgery versus those who have not. Thus, the objective here was to better understand whether anesthesia and/or surgery contribute to cognitive decline or an acceleration of Alzheimer's disease-related pathology in older adults.

METHODS

The authors enrolled 140 patients 60 yr or older undergoing major nonneurologic surgery and 51 nonsurgical controls via strata-based matching on age, sex, and years of education. CSF amyloid β (Aβ) 42, tau, and p-tau-181p levels and cognitive function were measured before and after surgery, and at the same time intervals in controls.

RESULTS

The groups were well matched on 25 of 31 baseline characteristics. There was no effect of group or interaction of group by time for baseline to 24-hr or 6-week postoperative changes in CSF Aβ, tau, or p-tau levels, or tau/Aβ or p-tau/Aβ ratios (Bonferroni P > 0.05 for all) and no difference between groups in these CSF markers at 1 yr (P > 0.05 for all). Nonsurgical controls did not differ from surgical patients in baseline cognition (mean difference, 0.19 [95% CI, -0.06 to 0.43]; P = 0.132), yet had greater cognitive decline than the surgical patients 1 yr later (β, -0.31 [95% CI, -0.45 to -0.17]; P < 0.001) even when controlling for baseline differences between groups. However, there was no difference between nonsurgical and surgical groups in 1-yr postoperative cognitive change in models that used imputation or inverse probability weighting for cognitive data to account for loss to follow up.

CONCLUSIONS

During a 1-yr time period, as compared to matched nonsurgical controls, the study found no evidence that older patients who underwent anesthesia and noncardiac, nonneurologic surgery had accelerated CSF Alzheimer's disease-related biomarker (tau, p-tau, and Aβ) changes or greater cognitive decline.

EDITOR’S PERSPECTIVE

Irreversible postoperative cognitive impairment after unruptured intracranial aneurysm treatment in the elderly

PURPOSE

Postoperative cognitive dysfunction and recovery remain unclear in older patients undergoing interventional therapies for unruptured intracranial aneurysms (UIAs). This study aimed to compare changes in postoperative cognitive function between younger and older patients and to detect factors associated with non-recovery from postoperative cognitive dysfunction.

METHODS

This study reviewed 59 consecutive patients with UIAs who underwent interventional therapies, including microsurgical clipping or endovascular treatment, from 2021 to 2022. All patients were divided into the older (aged ≥ 70 years) and younger (aged < 70 years) groups. Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB) were performed within 2 months before interventions, at 1 week postoperatively (POW1), and 3-6 months postoperatively (POM3-6).

RESULTS

MMSE and FAB scores decreased more frequently in the older group than in the younger group at POW1 (older vs. younger: MMSE: 48% vs. 21%, p < 0.05; FAB: 56% vs. 18%, p < 0.01). In the older group, the FAB Z-score decreased in POW1 and recovered by POM3-6 (p < 0.01), while the MMSE Z-score continued to decrease (p = 0.04). Age and the preoperative MSME Z-score were significantly associated with non-recovery from decreased MMSE score at POM3-6 (recovery vs. non-recovery, age: 62 years old vs. 72 years old, p = 0.03, preoperative MMSE Z-score: 0.16 vs. - 0.90, p < 0.01).

CONCLUSIONS

This retrospective study found that older patients were more likely to have a postoperative cognitive decline after UIA treatment and implicated that global cognitive function tended to decline more than executive function in the long term. In addition, this study demonstrated that lower preoperative cognitive function was associated with inadequate postoperative cognitive recovery. The findings potentially contribute to the establishment of indications for treating UIAs in older patients.

Postsurgery Subjective Cognitive and Short-Term Memory Impairment Among Middle-Aged Chinese Patients

Importance

Perioperative neurocognitive disorder, particularly postoperative cognitive impairment, is common and associated with multiple medical and social adversities, although data from China are lacking.

Objective

To examine the incidence, trajectory, and risk factors for subjective cognitive and short-term memory impairment after surgery in the Chinese population.

Design, Setting, and Participants

This cohort study used data from the China Surgery and Anesthesia Cohort to assess surgical patients aged 40 to 65 years from 2 medical centers between July 15, 2020, and March 31, 2023, with active follow-up within 1 year after the surgery. Of 11 158 patients who were successfully recruited (response rate, 94.4%), 10 149 participants were eligible and available for analysis. From this population, separate cohorts were constructed for analyzing subjective cognitive impairment (8105 noncardiac and 678 cardiac surgery patients) and short-term memory impairment (5246 noncardiac and 454 cardiac surgery patients).

Exposures

Twenty-four potential risk factors regarding comorbidities, preoperative psychological conditions, anesthesia- or surgery-related factors, and postsurgical events were included.

Main Outcomes and Measures

Outcomes included subjective cognitive function measured by the 8-Item Informant Interview to Differentiate Aging and Dementia (AD8; scores range from 0 to 8, with higher scores indicating more severe cognitive impairment) and short-term memory measured by the 3-Word Recall Test (TRT; scores range from 0 to 3, with lower scores indicating more severe short-term memory impairment) at 1, 3, 6, and 12 months after noncardiac and cardiac surgery. Generalized linear mixed models were used to identify risk factors associated with the presence of AD8 (score ≥2) or TRT (score <3) abnormality as well as the aggressively deteriorative trajectories of those cognitive measurements.

Results

For noncardiac surgery patients, the AD8 analysis included 8105 patients (mean [SD] age, 52.3 [7.1] years; 3378 [41.7%] male), and the TRT analysis included 5246 patients (mean [SD] age, 51.4 [7.0] years; 1969 [37.5%] male). The AD8 abnormality incidence rates after noncardiac surgery increased from 2.2% (175 of 8105) at 7 days to 17.1% (1059 of 6191) at 6 months after surgery, before appearing to decrease. In contrast, the TRT abnormality incidence rates followed a U-shaped pattern, with the most pronounced incidence rates seen at 7 days (38.9% [2040 of 5246]) and 12 months (49.0% [1394 of 2845]). Similar patterns were seen among cardiac surgery patients for the AD8 analysis (678 patients; mean [SD] age, 53.2 [6.3] years; 393 [58.0%] male) and TRT analysis (454 patients; mean [SD] age, 52.4 [6.4] years; 248 [54.6%] male). Among noncardiac surgery patients, the top risk factors for aggressively deteriorative AD8 trajectory and for AD8 abnormality, respectively, after surgery were preoperative sleep disturbances (Pittsburgh Sleep Quality Index ≥16 vs 0-5: odds ratios [ORs], 4.04 [95% CI, 2.20-7.40] and 4.54 [95% CI, 2.40-8.59]), intensive care unit stay of 2 days or longer (ORs, 2.43 [95% CI, 1.26-4.67] and 3.07 [95% CI, 1.67-5.65]), and preoperative depressive symptoms (ORs, 1.76 [95% CI, 1.38-2.24] and 2.23 [95% CI, 1.79-2.77]). Analyses for TRT abnormality and trajectory, as well as the analyses conducted among cardiac surgery patients, found fewer associated factors.

Conclusions and Relevance

This cohort study of middle-aged Chinese surgery patients found subjective cognitive and short-term memory impairment within 12 months after both cardiac and noncardiac surgery, with multiple identified risk factors, underscoring the potential of preoperative psychological interventions and optimized perioperative management for postoperative cognitive impairment prevention.

Processing speed test and 30-day readmission in elderly non-cardiac surgery patients- A retrospective study

Background and Aims

Preoperative cognitive function screening can help identify high-risk patients, but resource-intensive testing limits its widespread use. A novel self-administered tablet computer-based Processing Speed Test (PST) was used to assess cognitive "executive" function in non-cardiac surgery patients, but the relationship between preoperative test scores and postoperative outcomes is unclear. The primary outcome was a composite of 30-day readmission/death. The secondary outcome was a collapsed composite of discharge to a long-term care facility/death. Exploratory outcomes were 1) time to discharge alive, 2) 1-year mortality and 3) a collapsed composite of postoperative complications.

Methods

This retrospective study, after approval, was conducted in elective non-cardiac surgery patients ≥65 years old. We assessed the relationship between processing speed test scores and primary/secondary outcomes using multivariable logistic regression, adjusting for potential confounding variables.

Results

Overall 1568 patients completed the PST, and the mean ± standard deviation test score was 33 ± 10. The higher PST score is associated with better executive function. A 10-unit increase in the test score was associated with an estimated 19% lower 30-day readmission/death odds, with an odds ratio (OR) and 95% confidence interval (CI) of 0.81 (0.68, 0.96) (P = 0.015). Similarly, 10-unit increase in test score was associated with an estimated 26% lower odds of long-term care need/death, with OR (95% CI) of 0.74 (0.61, 0.91) (P = 0.004). We also found statistically significant associations between the test scores and time to discharge alive and to 1-year mortality, however, not with a composite of postoperative complications.

Conclusion

Elderly non-cardiac surgery patients with better PST scores were less likely to be readmitted, need long-term care after discharge or die within 30 days. Preoperative assessment of cognitive function using a simple self-administered test is feasible and may guide perioperative care.

The Effect of Low-Dose Esketamine on Postoperative Neurocognitive Dysfunction in Elderly Patients Undergoing General Anesthesia for Gastrointestinal Tumors: A Randomized Controlled Trial

Purpose

This study aims to evaluate the effects of the intraoperative application of low-dose esketamine on postoperative neurocognitive dysfunction (PND) in elderly patients undergoing general anesthesia for gastrointestinal tumors.

Methods

Sixty-eight elderly patients were randomly allocated to two groups: the esketamine group (group Es) (0.25 mg/kg loading, 0.125mg/kg/h infusion) and the control group (group C) (received normal saline). The primary outcome was the incidence of delayed neurocognitive recovery (DNR). The secondary outcomes were intraoperative blood loss, the total amount of fluid given during surgery, propofol and remifentanil consumption, cardiovascular adverse events, use of vasoactive drugs, operating and anesthesia time, the number of cases of sufentanil remedial analgesia, the incidence of postoperative delirium (POD), the intraoperative hemodynamics, bispectral index (BIS) value at 0, 1, 2 h after operation and numeric rating scale (NRS) pain scores within 3 d after surgery.

Results

The incidence of DNR in group Es (16.13%) was lower than in group C (38.71%) (P <0.05). The intraoperative remifentanil dosage and the number of cases of dopamine used in group Es were lower than in group C (P <0.05). Compared with group C, DBP was higher at 3 min after intubation, and MAP was lower at 30 min after extubation in group Es (P<0.05). The incidence of hypotension and tachycardia in group Es was lower than in group C (P <0.05). The NRS pain score at 3 d after surgery in group Es was lower than in group C (P <0.05).

Conclusion

Low-dose esketamine infusion reduced to some extent the incidence of DNR in elderly patients undergoing general anesthesia for gastrointestinal tumors, improved intraoperative hemodynamics and BIS value, decreased the incidence of cardiovascular adverse events and the intraoperative consumption of opioids, and relieved postoperative pain.

Oscillatory and aperiodic neuronal activity in working memory following anesthesia

OBJECTIVE

Anesthesia and surgery are associated with cognitive impairment, particularly memory deficits. So far, electroencephalography markers of perioperative memory function remain scarce.

METHODS

We included male patients >60 years scheduled for prostatectomy under general anesthesia. We obtained neuropsychological assessments and a visual match-to-sample working memory task with simultaneous 62-channel scalp electroencephalography 1 day before and 2 to 3 days after surgery.

RESULTS

Twenty-six patients completed both pre- and postoperative sessions. Compared with preoperative performance, verbal learning deteriorated after anesthesia (California Verbal Learning Test total recall; t₂₅ = -3.25, p = 0.015, d = -0.902), while visual working memory performance showed a dissociation between match and mismatch accuracy (match*session F_1,25 = 3.866, p = 0.060). Better verbal learning was associated with an increase of aperiodic brain activity (total recall r = 0.66, p = 0.029, learning slope r = 0.66, p = 0.015), whereas visual working memory accuracy was tracked by oscillatory theta/alpha (7 - 9 Hz), low beta (14 - 18 Hz) and high beta/gamma (34 - 38 Hz) activity (matches: p < 0.001, mismatches: p = 0.022).

CONCLUSIONS

Oscillatory and aperiodic brain activity in scalp electroencephalography track distinct features of perioperative memory function.

SIGNIFICANCE

Aperiodic activity provides a potential electroencephalographic biomarker to identify patients at risk for postoperative cognitive impairments.

Peri-Operative Risk Factors Associated with Post-Operative Cognitive Dysfunction (POCD): An Umbrella Review of Meta-Analyses of Observational Studies

This umbrella review aimed to systematically identify the peri-operative risk factors associated with post-operative cognitive dysfunction (POCD) using meta-analyses of observational studies. To date, no review has synthesised nor assessed the strength of the available evidence examining risk factors for POCD. Database searches from journal inception to December 2022 consisted of systematic reviews with meta-analyses that included observational studies examining pre-, intra- and post-operative risk factors for POCD. A total of 330 papers were initially screened. Eleven meta-analyses were included in this umbrella review, which consisted of 73 risk factors in a total population of 67,622 participants. Most pertained to pre-operative risk factors (74%) that were predominantly examined using prospective designs and in cardiac-related surgeries (71%). Overall, 31 of the 73 factors (42%) were associated with a higher risk of POCD. However, there was no convincing (class I) or highly suggestive (class II) evidence for associations between risk factors and POCD, and suggestive evidence (class III) was limited to two risk factors (pre-operative age and pre-operative diabetes). Given that the overall strength of the evidence is limited, further large-scale studies that examine risk factors across various surgery types are recommended.

Non-pharmacological prevention of postoperative delirium by occupational therapy teams: A randomized clinical trial

Background

Patients who develop postoperative delirium (POD) have several clinical complications, such as increased morbidity, increased hospital stays, higher hospital costs, cognitive and functional impairment, and higher mortality. POD is a clinical condition preventable by standard non-pharmacological measures An intensive Occupational Therapy (OT) intervention has been shown to be highly effective in preventing delirium in critically ill medical patients, but it is unknown the effect in surgical patients. Thus, we designed a prospective clinical study with the aim to determine whether patients undergoing intervention by the OT team have a lower incidence of POD compared to the group treated only with standard measures.

Methods

A multicenter, single-blind, randomized clinical trial was conducted between October 2018 and April 2021, in Santiago of Chile, at a university hospital and at a public hospital. Patients older than 75 years undergoing elective major surgery were eligible for the trial inclusion. Patients with cognitive impairment, severe communication disorder and cultural language limitation, delirium at admission or before surgery, and enrolled in another study were excluded. The intervention consisted of OT therapy twice a day plus standard internationally recommended non-pharmacological prevention intervention during 5 days after surgery. Our primary outcome was development of delirium and postoperative subsyndromal delirium.

Results

In total 160 patients were studied. In the interventional group, treated with an intensive prevention by OT, nine patients (12.9%) developed delirium after surgery and in the control group four patients (5.5%) [p = 0.125, RR 2.34 CI 95 (0.75-7.27)]. Whereas subsyndromal POD was present in 38 patients in the control group (52.1%) and in 34 (48.6%) in the intervention group [p = 0.4, RR 0.93 CI95 (0.67-1.29)]. A post hoc analysis determined that the patient's comorbidity and cognitive status prior to hospitalization were the main risk factors to develop delirium after surgery.

Discussion

Patients undergoing intervention by the OT team did not have a lower incidence of POD compared to the group treated only with standard non-pharmacological measures in adults older than 75 years who went for major surgery.

Clinical trial registration

www.ClinicalTrials.gov, identifier NCT03704090.

Perioperative Neurofilament Light Plasma Concentrations and Cognition before and after Cardiac Surgery: A Prospective Nested Cohort Study

BACKGROUND

Neurofilament light is a marker of neuronal injury and can be measured in blood. Postoperative increases in neurofilament light have been associated with delirium after noncardiac surgery. However, few studies have examined the association of neurofilament light changes with postdischarge cognition in cardiac surgery patients, who are at highest risk for neuronal injury and cognitive decline. The authors hypothesized that increased neurofilament light (both baseline and change) would be associated with worse neuropsychological status up to 1 yr after cardiac surgery.

METHODS

This observational study was nested in a trial of cardiac surgery patients, in which blood pressure during bypass was targeted using cerebral autoregulation monitoring. Plasma concentrations of neurofilament light were measured at baseline and postoperative day 1. Neuropsychological testing was performed at baseline, 1 month after surgery, and 1 yr after surgery. Primary outcomes were baseline and change from baseline in a composite z-score of all cognitive tests.

RESULTS

Among 167 patients, cognitive outcomes were available in 80% (134 of 167) and 61% (102 of 167) at 1 month and 1 yr after surgery, respectively. The median baseline concentration of neurofilament light was 18.2 pg/ml (interquartile range, 13.4 to 28.1), and on postoperative day 1 was 28.5 pg/ml (interquartile range, 19.3 to 45.0). Higher baseline log neurofilament light was associated with worse baseline cognitive z-score (adjusted slope, -0.60; 95% CI, -0.90 to -0.30; P < 0.001), no change in z-score from baseline to 1 month (0.11; 95% CI, -0.19 to 0.41; P = 0.475), and improvement in z-score from baseline to 1 yr (0.56; 95% CI, 0.31 to 0.81; P < 0.001). Whereas some patients had an improvement in cognition at 1 yr and others a decline, an increase in neurofilament light from baseline to postoperative day 1 was associated with a greater decline in cognition at 1 yr.

CONCLUSIONS

Higher baseline neurofilament light concentration was associated with worse baseline cognition but improvement in cognition at 1 yr. A postoperative increase in neurofilament light was associated with a greater cognitive decline at 1 yr.

EDITOR’S PERSPECTIVE

Potential Markers of Neurocognitive Disorders After Cardiac Surgery: A Bibliometric and Visual Analysis

Background

Identifying useful markers is essential for diagnosis and prevention of perioperative neurocognitive disorders (PNDs). Here, we attempt to understand the research basis and status, potential hotspots and trends of predictive markers associated with PNDs after cardiac surgery via bibliometric analysis.

Methods

A total of 4,609 original research articles and reviews that cited 290 articles between 2001 and 2021 were obtained from the Web of Science Core Collection (WoSCC) as the data source. We used the software CiteSpace to generate and analyze visual networks of bibliographic information, including published years and journals, collaborating institutions, co-cited references, and co-occurring keywords.

Results

The number of annual and cumulative publications from 2001 to 2021 has been increasing on the whole. The Harvard Medical School was a very prolific and important institution in this field. The journal of Ann Thorac Surg (IF 4.33) had the most publications, while New Engl J Med was the most cited journal. Neuron-specific enolase (NSE), S100b and kynurenic acid (KYNA) were frequently discussed as possible markers of PNDs in many references. Cardiopulmonary bypass (CPB) was a keyword with high frequency (430) and sigma (6.26), and inflammation was the most recent burst keyword.

Conclusion

Potential markers of PNDs has received growing attention across various disciplines for many years. The research basis mainly focuses on three classic biomarkers of S100b, NSE, and KYNA. The most active frontiers are the inflammation-related biomarkers (e.g., inflammatory cells, cytokines, or mediators) and surgery-related monitoring parameters (e.g., perfusion, oxygen saturation, and the depth of anesthesia).

Surgical Hospitalization Is Not Associated With Cognitive Trajectory Over 6 Years in Healthy Older Australians

OBJECTIVE

The aim was to investigate the association of cognitive trajectories and overnight surgical hospitalization in older adults, while controlling for and comparing with the association with acute medical hospitalizations.

DESIGN

This is a secondary analysis of data from a population-based, longitudinal cohort study of older Australians.

SETTING AND PARTICIPANTS

Cognition was assessed with 4 biennial waves of prospective neuropsychological data from 1026 Sydney Memory and Aging Study participants age 70 to 90 years at baseline. Hospitalization exposure was obtained from 10 years of electronically linked data from the New South Wales Admitted Patient Data Collection.

METHODS

Latent growth curve modeling estimated global cognition z score baseline and slope over 6 years, and the effects of contemporaneous surgical and medical hospitalization predictors while controlling for potential demographic and comorbidity confounders.

RESULTS

After controlling for confounding variables, this analysis showed that overnight surgical hospitalizations were not associated with worse baseline global cognition or accelerated cognitive decline over 6 years. This was despite this cohort having more surgeries and more complex surgeries compared with Australian data for overnight hospitalizations in over 70-year-olds. Conversely, recent medical hospitalizations were associated with accelerated cognitive decline.

CONCLUSIONS AND IMPLICATIONS

This analysis finds that surgery and anesthesia are unlikely to be risk factors for medium to long-term global cognitive decline in healthy older adults, while controlling for contemporaneous medical hospitalizations. These findings are contrary to prior conclusions from several surgical studies that may have been impeded by insufficient comparison groups. They are, however, consistent with recent population-based studies suggesting surgery has minimal association with cognitive decline in the medium to long-term. Future research needs to clarify the association of surgical hospitalization with the full spectrum of cognitive outcomes including subjective cognitive complaints and dementia, and importantly, how these cognitive outcomes correlate with clinically significant functional changes.

Potential Neuroprotective Role of Sugammadex: A Clinical Study on Cognitive Function Assessment in an Enhanced Recovery After Cardiac Surgery Approach and an Experimental Study

Background

Postoperative cognitive dysfunction affects the quality of recovery, particularly affecting the elderly, and poses a burden on the health system. We hypothesize that the use of sugammadex (SG) could optimize the quality of postoperative cognitive function and overall recovery through a neuroprotective effect.

Methods

A pilot observational study on patients undergoing cardiac surgery with enhanced recovery after cardiac surgery (ERACS) approach, was designed to compare SG-treated (n = 14) vs. neostigmine (NG)-treated (n = 7) patients. The Postoperative Quality Recovery Scale (PQRS) was used at different times to evaluate cognitive function and overall recovery of the patients. An online survey among anesthesiologists on SG use was also performed. Additionally, an animal model study was designed to explore the effects of SG on the hippocampus.

Results

Sugammadex (SG) was associated with favorable postoperative recovery in cognitive domains particularly 30 days after surgery in patients undergoing aortic valve replacement by cardiopulmonary bypass and the ERACS approach; however, it failed to demonstrate a short-term decrease in length of intensive care unit (ICU) and hospital stay. The survey information indicated a positive appreciation of SG recovery properties. SG reverts postoperative memory deficit and induces the expression of anti-inflammatory microglial markers.

Conclusion

The results show a postoperative cognitive improvement by SG treatment in patients undergoing aortic valve replacement procedure by the ERACS approach. Additionally, experimental data from an animal model of mild surgery confirm the cognitive effect of SG and suggest a potential effect over glia cells as an underlying mechanism.

Postoperative changes in cognition and cerebrospinal fluid neurodegenerative disease biomarkers

OBJECTIVE

Numerous investigators have theorized that postoperative changes in Alzheimer's disease neuropathology may underlie postoperative neurocognitive disorders. Thus, we determined the relationship between postoperative changes in cognition and cerebrospinal (CSF) tau, p-tau-181p, or Aβ levels after non-cardiac, non-neurologic surgery in older adults.

METHODS

Participants underwent cognitive testing before and 6 weeks after surgery, and lumbar punctures before, 24 h after, and 6 weeks after surgery. Cognitive scores were combined via factor analysis into an overall cognitive index. In total, 110 patients returned for 6-week postoperative testing and were included in the analysis.

RESULTS

There was no significant change from before to 24 h or 6 weeks following surgery in CSF tau (median [median absolute deviation] change before to 24 h: 0.00 [4.36] pg/mL, p = 0.853; change before to 6 weeks: -1.21 [3.98] pg/mL, p = 0.827). There were also no significant changes in CSF p-tau-181p or Aβ over this period. There was no change in cognitive index (mean [95% CI] 0.040 [-0.018, 0.098], p = 0.175) from before to 6 weeks after surgery, although there were postoperative declines in verbal memory (-0.346 [-0.523, -0.170], p = 0.003) and improvements in executive function (0.394, [0.310, 0.479], p < 0.001). There were no significant correlations between preoperative to 6-week postoperative changes in cognition and CSF tau, p-tau-181p, or Aβ42 changes over this interval (p > 0.05 for each).

INTERPRETATION

Neurocognitive changes after non-cardiac, non-neurologic surgery in the majority of cognitively healthy, community-dwelling older adults are unlikely to be related to postoperative changes in AD neuropathology (as assessed by CSF Aβ, tau or p-tau-181p levels or the p-tau-181p/Aβ or tau/Aβ ratios).

TRIAL REGISTRATION

clinicaltrials.gov (NCT01993836).

Safety and Efficacy of Ketamine-Fentanyl-Dexmedetomidine-Induced Anesthesia and Analgesia in Neonatal and Aged Rats

The efficiency of many anesthetic regimens is controversial, with side effects especially in the vulnerable children and old population. The study aimed to evaluate the safety and efficacy of low-dose combination of ketamine, fentanyl, and dexmedetomidine (KFD) for anesthesia and analgesia in the neonatal and elderly rats. KFD rapidly induced anesthesia and analgesia in either postnatal days 6 (P6) or 13 months (13M) old rats. Meanwhile, KFD administration had no adverse effects on the cardiovascular and respiratory systems. Compared with control group, there were no distinct morphologic changes in kidney, liver, and brain in KFD group. Moreover, administration of KFD had no influence on hepatic and renal function in rats of both ages. Furthermore, there was no obvious difference in cognitive function between control and KFD groups. These results indicated that the administration of KFD combination offered safe and efficient anesthesia. Collectively, our results suggest the potential implication of the KFD combination in anesthesia management.

The potential for autonomic neuromodulation to reduce perioperative complications and pain: a systematic review and meta-analysis

BACKGROUND

Autonomic dysfunction promotes organ injury after major surgery through numerous pathological mechanisms. Vagal withdrawal is a key feature of autonomic dysfunction, and it may increase the severity of pain. We systematically evaluated studies that examined whether vagal neuromodulation can reduce perioperative complications and pain.

METHODS

Two independent reviewers searched PubMed, EMBASE, and the Cochrane Register of Controlled Clinical Trials for studies of vagal neuromodulation in humans. Risk of bias was assessed; I2 index quantified heterogeneity. Primary outcomes were organ dysfunction (assessed by measures of cognition, cardiovascular function, and inflammation) and pain. Secondary outcomes were autonomic measures. Standardised mean difference (SMD) using the inverse variance random-effects model with 95% confidence interval (CI) summarised effect sizes for continuous outcomes.

RESULTS

From 1258 records, 166 full-text articles were retrieved, of which 31 studies involving patients (n=721) or volunteers (n=679) met the inclusion criteria. Six studies involved interventional cardiology or surgical patients. Indirect stimulation modalities (auricular [n=23] or cervical transcutaneous [n=5]) were most common. Vagal neuromodulation reduced pain (n=10 studies; SMD=2.29 [95% CI, 1.08-3.50]; P=0.0002; I2=97%) and inflammation (n=6 studies; SMD=1.31 [0.45-2.18]; P=0.003; I2=91%), and improved cognition (n=11 studies; SMD=1.74 [0.96-2.52]; P<0.0001; I2=94%) and cardiovascular function (n=6 studies; SMD=3.28 [1.96-4.59]; P<0.00001; I2=96%). Five of six studies demonstrated autonomic changes after vagal neuromodulation by measuring heart rate variability, muscle sympathetic nerve activity, or both.

CONCLUSIONS

Indirect vagal neuromodulation improves physiological measures associated with limiting organ dysfunction, although studies are of low quality, are susceptible to bias and lack specific focus on perioperative patients.

In-Hospital Delirium as a Prognostic Factor for New Cognitive Disorder in a 1-Year Post-Hip Fracture Follow-Up

BACKGROUND

Older hip fracture patients are at high risk of delirium during acute hospital care. Pre-fracture dementia is known to increase the risk of in-hospital delirium. Data on the development of new cognitive disorders in patients with delirium are scarce.

OBJECTIVE

The objective of this study is to evaluate the prognostic significance of in-hospital delirium on the development of new cognitive disorders in a 1-year follow-up in older hip fracture patients.

MATERIAL AND METHODS

Data consisted of 476 hip fracture patients aged 65 years or more with no known cognitive disorder on admission. Delirium was assessed using the Confusion Assessment Method (CAM). Cognitive disorders were diagnosed following the national guidelines. Information on the new diagnoses of cognitive disorders (NDCD) at 1-year follow-up was elicited in a telephone interview and confirmed from the electronic patient files. Logistic regression analyses were conducted to examine the association of delirium with NDCDs.

RESULTS

Of the 476 patients, 87 (18%) had delirium during hospital stay. Patients with delirium were older, they had poorer nutritional status, lower mobility level, and more supported living arrangements than did patients without delirium. At the 1-year time point, 205 (43%) had NDCDs or were strongly suspected of this. CAM result was statistically significantly associated with development of NDCD in multivariable-adjusted analysis (odds ratio [OR] 2.29; 95% confidence interval [CI]: 1.39-3.79). Also, poor nutritional status continued to be associated with NDCDs (multivariable-adjusted OR 1.58; 95% CI: 1.03-2.43).

CONCLUSION

Delirium during hospitalization and poor nutritional status on admission are independent prognostic factors for development of subsequent cognitive disorders in older hip fracture patients.

Neuroprotective effects of dynamic bubble trap use in patients undergoing pulmonary endarterectomy: a two-arm randomized controlled trial

Background

During cardiosurgical procedures that use extracorporeal circulation (ECC), a variety of neurological complications can occur, and postoperative cognitive deficits remain an unsolved problem. Among the sources of these complications are intraoperatively detectable cerebral microemboli, which mainly consist of air. This study's purpose was to assess neuroprotective effects of reducing these gaseous microemboli using a dynamic bubble trap (DBT) in patients undergoing pulmonary endarterectomy (PEA) for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH).

Methods

Patients undergoing PEA were randomly assigned to receive either a DBT (n=47) or no additional device (controls, n=46) during ECC. Neuropsychological testing was performed before and 3 months after PEA. The primary endpoint was cognitive improvement in the DBT group (n=29) compared with the control group (n=42). As secondary endpoint, ischemic brain micro-lesions were analyzed on postoperative days 6 through 10 using diffusion-weighted magnetic resonance imaging (MRI).

Results

Analysis of interaction effects revealed improved performance in visual long-term memory (P=0.008, η²=0.099), verbal long-term memory (P=0.030, η²=0.067), verbal short-term memory (P=0.014, η²=0.083), and attention and processing speed (P=0.043, η²=0.056) from pre- to post-testing in the DBT group compared to control group. In MRI, postoperative ischemic micro-lesions could only be detected in one patient; another patient suffered a severe bihemispheric embolic stroke.

Conclusions

DBT positively influences memory function after PEA. This effect is most likely caused by the reduction of gaseous microemboli.

Trial Registration

This study is registered in the German Clinical Trials Register, ID: DRKS00021499.

Association of postoperative delirium with cognitive outcomes: A meta-analysis

STUDY OBJECTIVE

To determine the association between postoperative delirium (POD) and cognitive outcomes at least 1 month after surgery in elderly patients, and synthesize the dynamic risk trajectory of cognition impairment after POD.

DESIGN

Meta-analysis searching PubMed, Cochrane and EMBASE from inception to November 1, 2020. The terms postoperative delirium, delirium after surgery, postsurgical delirium, postoperative cogniti*, postoperative cognitive dysfunction, postoperative cognition decline, cognitive decline, cognitive impair* and dement* were searched alone or in combination.

MEASUREMENTS

Inclusion criteria were prospective cohort studies investigating the association between POD and cognitive outcomes in patients aged ≥60 years underwent surgery. The primary outcome was the association between POD and cognitive outcomes at 1 or more months after surgery. We considered cognitive outcomes measured up to 12 months after surgery as short-term and beyond 12 months as long-term. Two authors performed the study screening, data extraction and quality assessments. Effect sizes were calculated as Hedges g or Odds ratio (OR) based on random- and fixed-effects models. Meta-regression was conducted to analyze the role of potential contributors to heterogeneity.

MAIN RESULTS

Eighteen studies were included. Our result showed a significant and medium association between POD and cognitive outcomes after at least 1 month postoperatively (g = 0.61 95% CI 0.43-0.79; I² = 65.1%), indicating that patients with POD were associated with worse cognitive outcomes. The association of POD with short- and long-term cognitive impairment were also both significant (short-term: g = 0.46 95% CI 0.24-0.68; I² = 53.1%; and long-term: g = 0.82 95% CI 0.57-1.06; I² = 57.1%). A multivariate meta-regression suggested that age and measure of delirium were significant sources of heterogeneity. POD was also associated with the significant risk for dementia (OR = 6.08 95% CI 3.80-9.72; I² = 0) as well as attention (OR = 1.74 95% CI 1.13-2.68; I² = 0), executive (OR = 1.33 95% CI 1.00-1.80; I² = 0) and memory impairment (OR = 1.59 95% CI 1.20-2.10; I² = 43.0%). Additionally, our results showed that the risk trajectory for cognitive decline associated with POD within five years after surgery revealed exponential growth.

CONCLUSIONS

This is the first meta-analysis quantifying the association between POD and cognitive outcomes. Our results showed that POD was significantly associated with worse cognitive outcomes, including short- and long-term cognitive outcomes following surgery.

Physostigmine for prevention of postoperative delirium and long-term cognitive dysfunction in liver surgery: A double-blinded randomised controlled trial

BACKGROUND

Anecdotally, cholinergic stimulation has been used to treat delirium and reduce cognitive dysfunction.

OBJECTIVE

The aim of this investigation was to evaluate whether physostigmine reduced the incidence of postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) in patients undergoing liver resection.

DESIGN

This was a double-blind, randomised, placebo-controlled trial. Between 11 August 2009 and 3 March 2016, patients were recruited at the Charité - Universitätsmedizin Berlin in Germany. Follow-ups took place at 1 week (T1), 90 days (T2) and 365 days (T3) after surgery.

SETTING

This single-centre study was conducted at an academic medical centre.

PARTICIPANTS

In total, 261 participants aged at least 18 years scheduled for elective liver surgery were randomised. The protocol also included 45 non-surgical matched controls to provide normative data for POCD and neurocognitive deficit (NCD).

INTERVENTION

Participants were allocated to receive either intravenous physostigmine, as a bolus of 0.02 mg kg-1 body weight followed by 0.01 mg kg-1 body weight per hour (n = 130), or placebo (n = 131), for 24 h after induction of anaesthesia.

MAIN OUTCOMES AND MEASURES

Primary outcomes were POD, assessed using the Diagnostic and Statistical Manual of Mental Disorders (DSM-4-TR) twice daily up to day 7 after surgery, and POCD assessed via the CANTAB neuropsychological test battery, and two paper pencil tests on the day before surgery, and on postoperative days 7, 90 and 365.

RESULTS

In total, 261 patients were randomised, 130 to the physostigmine and 131 to the placebo group. The incidence of POD did not differ significantly between the physostigmine and placebo groups (20 versus 15%; P = 0.334). Preoperative cognitive impairment and POCD frequencies did not differ significantly between the physostigmine and placebo groups at any time. Lower mortality rates were found in the physostigmine group compared with placebo at 3 months [2% (95% confidence interval (CI), 0 to 4) versus 11% (95% CI, 6 to 16), P = 0.002], and 6 months [7% (95% CI, 3 to 12) versus 16% (95% CI, 10 to 23), P = 0.012] after surgery.

CONCLUSION

Physostigmine had no effect on POD and POCD when applied after induction of anaesthesia up to 24 h.

TRIAL REGISTRATION

DOI 10.1186/ISRCTN18978802, EudraCT 2008-007237-47, Ethics approval ZS EK 11 618/08 (15 January 2009).

Neuropsychological Tests in Post-operative Cognitive Dysfunction: Methods and Applications

Post-operative cognitive dysfunction (POCD) is a neurological complication that relatively frequently occurs in older people after anesthesia/surgery, with varying durations and significant differences in the severity of cognitive impairment. POCD is mainly characterized by memory loss mostly without consciousness disorders, accompanied by abnormal emotions, behaviors, and language, mostly without consciousness disorder. The clinical performance of POCD lacks specificity but can reflect the severity of cognitive impairment in patients. The diagnosis of POCD cannot be separated from the evaluation of perioperative cognitive function of patients, and the more popular and accepted method is neuropsychological tests (NPTs).

The international ENIGMA-II substudy on postoperative cognitive disorders (ISEP)

There is a large controversy as to whether nitrous oxide (N₂O) added to the anaesthetic gas mixture is harmful or harmless for postoperative cognitive function recovery. We performed a nested study in the ENIGMA-II trial and compared postoperative neurocognitive recovery of patients randomly receiving N₂O (70%) or Air (70%) in 30% O₂ during anesthesia. We included adults having non cardiac surgery. We compared recovery scores for episodic memory, decision making/processing speed and executive functions measured with the computerised Cambridge Neuropsychological Test Automated Battery (CANTAB). Assessments were performed at baseline, seven and ninety days. At first interim analysis, following recruitment of 140 participants, the trial was suspended. We found that the mean (95%CI) changes of scores for episodic memory were in the Pocock futility boundaries. Decision making/processing speed did not differ either between groups (P > 0.182). But for executive functions at seven days, the mean number (95% CI) of problems successfully solved and the number of correct box choices made was higher in the N2O group, P = 0.029. N₂O with the limitations of an interim analysis appears to have no harmful effect on cognitive functions (memory/processing speed). It may improve the early recovery process of executive functions. This preliminary finding warrants further investigations.

Association of Coronary Artery Bypass Grafting vs Percutaneous Coronary Intervention With Memory Decline in Older Adults Undergoing Coronary Revascularization

IMPORTANCE

It is uncertain whether coronary artery bypass grafting (CABG) is associated with cognitive decline in older adults compared with a nonsurgical method of coronary revascularization (percutaneous coronary intervention [PCI]).

OBJECTIVE

To compare the change in the rate of memory decline after CABG vs PCI.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of community-dwelling participants in the Health and Retirement Study, who underwent CABG or PCI between 1998 and 2015 at age 65 years or older. Data were modeled for up to 5 years preceding and 10 years following revascularization or until death, drop out, or the 2016-2017 interview wave. The date of final follow-up was November 2017.

EXPOSURES

CABG (including on and off pump) or PCI, ascertained from Medicare fee-for-service billing records.

MAIN OUTCOMES AND MEASURES

The primary outcome was a summary measure of cognitive test scores and proxy cognition reports that were performed biennially in the Health and Retirement Study, referred to as memory score, normalized as a z score (ie, mean of 0, SD of 1 in a reference population of adults aged ≥72 years). Memory score was analyzed using multivariable linear mixed-effects models, with a prespecified subgroup analysis of on-pump and off-pump CABG. The minimum clinically important difference was a change of 1 SD of the population-level rate of memory decline (0.048 memory units/y).

RESULTS

Of 1680 participants (mean age at procedure, 75 years; 41% female), 665 underwent CABG (168 off pump) and 1015 underwent PCI. In the PCI group, the mean rate of memory decline was 0.064 memory units/y (95% CI, 0.052 to 0.078) before the procedure and 0.060 memory units/y (95% CI, 0.048 to 0.071) after the procedure (within-group change, 0.004 memory units/y [95% CI, -0.010 to 0.018]). In the CABG group, the mean rate of memory decline was 0.049 memory units/y (95% CI, 0.033 to 0.065) before the procedure and 0.059 memory units/y (95% CI, 0.047 to 0.072) after the procedure (within-group change, -0.011 memory units/y [95% CI, -0.029 to 0.008]). The between-group difference-in-differences estimate for memory decline for PCI vs CABG was 0.015 memory units/y (95% CI, -0.008 to 0.038; P = .21). There was statistically significant increase in the rate of memory decline after off-pump CABG compared with after PCI (difference-in-differences: mean increase in the rate of decline of 0.046 memory units/y [95% CI, 0.008 to 0.084] after off-pump CABG), but not after on-pump CABG compared with PCI (difference-in-differences: mean slowing of decline of 0.003 memory units/y [95% CI, -0.024 to 0.031] after on-pump CABG).

CONCLUSIONS AND RELEVANCE

Among older adults undergoing coronary revascularization with CABG or PCI, the type of revascularization procedure was not significantly associated with differences in the change of rate of memory decline.

Apolipoprotein E ε4 and cognitive function after surgery in middle-aged and elderly Danish twins

BACKGROUND

Transient cognitive impairment is common in adult patients of all ages following anaesthesia and surgery. Apolipoprotein E (APOE) ε4 carriers may have a larger deterioration in short-term cognitive function after major surgery compared with APOE ε4 noncarriers.

OBJECTIVES

The aim was to examine the effect of APOE ε4 on the association between exposure to surgery and anaesthesia, and subsequent cognitive functioning. A more pronounced deterioration in cognitive function in APOE ε4 carriers was hypothesised.

DESIGN

An observational cross-sectional and a 6 to 10 years longitudinal twin cohort design.

SETTING

Survey and register study of 2936 Danish twins aged 45 to 92 years.

MAIN OUTCOME MEASURES

Cognitive function was assessed using five age-sensitive cognitive tests. In the cross-sectional study, we compared twins exposed to surgery with a reference group (unexposed). Linear regression models were used adjusting for sex and age and stratified by APOE ε4 carrier status. In the longitudinal cognitive follow-up study 1671 twins participated. Intrapair analyses were also performed using 70 same-sexed twin pairs concordant for APOE ε4 carrier status, but discordant for major surgery.

RESULTS

APOE ε4 carriers had lower cognitive scores compared with noncarriers, and this was statistically significant in elderly twins 70+ years of age (mean difference, -0.67; 95% CI, -1.14 to -0.17). There was no significant impact on cognitive function after surgery according to APOE ε4 carrier status in the cross-sectional study. Similarly, there was no APOE ε4 modification in the longitudinal study. Also, in the intrapair analyses no evidence was found of lower cognitive score after major surgery compared with the nonexposed cotwins among APOE ε4 carriers.

CONCLUSION

No evidence was found of more pronounced long-term deterioration in cognitive function after surgery among APOE ε4 carriers, but elderly APOE ε4 carriers in general performed worse on the cognitive tests than noncarriers.

Intraoperative impaired cerebrovascular autoregulation and delayed neurocognitive recovery after major oncologic surgery: a secondary analysis of pooled data

Cerebral blood flow is tightly regulated by cerebrovascular autoregulation (CVA), and intraoperative impairment of CVA has been linked with perioperative neurocognitive disorders. We aim to assess whether impairment of CVA during major oncologic surgery is associated with delayed neurocognitive recovery (DNCR) postoperatively. We performed a secondary analysis of prospectively collected data. Patients were included if they had undergone complete pre- and postoperative neuropsychological assessments, continuous intraoperative measurement of CVA, and major oncologic surgery for visceral, urological, or gynecological cancer. Intraoperative CVA was measured using the time-correlation method based on near-infrared-spectroscopy, and DNCR was assessed with a neuropsychological test battery. A decline in cognitive function before hospital discharge compared with a preoperative baseline assessment was defined as DNCR. One hundred ninety-five patients were included in the analysis. The median age of the study population was 65 years (IQR: 60–68); 11 patients (5.6%) were female. Forty-one patients (21.0%) fulfilled the criteria for DNCR in the early postoperative period. We found a significant association between impaired intraoperative CVA and DNCR before hospital discharge (OR = 1.042 [95% CI: 1.005; 1.080], p = 0.028). The type of surgery (radical prostatectomy vs. other major oncologic surgery; OR = 0.269 [95% CI: 0.099; 0.728], p = 0.010) and premedication with midazolam (OR = 3.360 [95% CI: 1.039; 10.870], p = 0.043) were significantly associated with the occurrence of DNCR in the early postoperative period. Intraoperative impairment of CVA is associated with postoperative neurocognitive function early after oncologic surgery. Therefore, intraoperative monitoring of CVA may be a target for neuroprotective interventions. The initial studies were retrospectively registered with primary clinical trial registries recognized by the World Health Organization (ClinicalTrials.gov Identifiers: DRKS00010014, 21.03.2016 and NCT04101006, 24.07.2019).

Methodology of measuring postoperative cognitive dysfunction: a systematic review

BACKGROUND

Postoperative cognitive dysfunction (POCD) is an adverse outcome that impacts patients' quality of life. Its diagnosis relies on formal cognitive testing performed before and after surgery. The substantial heterogeneity in methodology limits comparability and meta-analysis of studies. This systematic review critically appraises the methodology of studies on POCD published since the 1995 Consensus Statement and aims to provide guidance to future authors by providing recommendations that may improve comparability between future studies.

METHODS

This systematic review of literature published between 1995 and 2019 included studies that used baseline cognitive testing and a structured cognitive test battery, and had a minimal follow-up of 1 month. For cohorts with multiple publications, data from the primary publication were supplemented with available data from later follow-up studies.

RESULTS

A total of 274 unique studies were included in the analysis. In the included studies, 259 different cognitive tests were used. Studies varied considerably in timing of assessment, follow-up duration, definition of POCD, and use of control groups. Of the 274 included studies, 70 reported POCD as a dichotomous outcome at 1 to <3 months, with a pooled incidence of 2998/10 335 patients (29.0%).

CONCLUSIONS

We found an overwhelming heterogeneity in methodology used to study POCD since the publication of the 1995 Consensus Statement. Future authors could improve study quality and comparability through optimal timing of assessment, the use of commonly used cognitive tests including the Consensus Statement 'core battery', application of appropriate cut-offs and diagnostic rules, and detailed reporting of the methods used.

PROSPERO REGISTRY NUMBER

CRD42016039293.

TNF-α - mediated peripheral and central inflammation are associated with increased incidence of PND in acute postoperative pain

Background

Acute postoperative pain plays an important role in the perioperative neurocognitive disorders (PND). The pathogenesis of PND is still unknown, but it is generally believed that peripheral and central nervous system inflammation play an important role, and acute postoperative pain is also thought to aggravate postoperative inflammatory response. The aim of the present study is to explore the effect of acute postoperative pain on peripheral and central nervous system inflammation and related cognitive impairment behaviour in elderly rats after surgery.

Methods

Rats were assigned into four groups: control, surgery for internal fixation for tibial fracture, surgery with analgesia using intraperitoneal morphine, and morphine without surgery. Pain was assessed by the Subjective Pain Scale. The spatial memory of rats was assessed by the Morris water maze (delayed matching task) from the second day to the seventh day after surgery (POD2-POD7). In part of the rats, the pro-inflammatory cytokines TNF-α in plasma, the medial prefrontal cortex (mPFC), and the hippocampus were determined by ELISA on the POD2. The activation of microglia and the expression of c-Fos in the hippocampal CA1 regions and mPFC were detected by the immunohistochemical method on the POD2.

Results

Acute postoperative pain and spatial memory impairment occurred after operation, and postoperative analgesia could significantly improve the both parameters. Additionally, on the POD2, the levels of TNF-α in plasma, hippocampus and mPFC were significantly increased, while the activation of microglia cells and the expression c-Fos in the hippocampal CA1 regions and mPFC were significantly increased. And postoperative analgesia with morphine significantly inhibited the above reactions.

Conclusion

Our data suggest that acute postoperative pain increases the incidence of perioperative neurocognitive disorders. Peripheral and central nervous system inflammation may be involved in this cognitive impairment. And reducing the intensity of acute postoperative pain may be one of the main preventive strategies for PND.

Association of Hospitalization with Long-Term Cognitive Trajectories in Older Adults

IMPORTANCE

Hospitalizations are associated with cognitive decline in older adults.

OBJECTIVE

To determine the association between hospitalization characteristics and the trajectory of cognitive function in older adults.

DESIGN

Population-based longitudinal study of cognitive aging.

SETTING

Olmsted Medical Center and Mayo Clinic, the only centers in Olmsted County, Minnesota, with hospitalization capacity.

PARTICIPANTS

Individuals without dementia at baseline, with consecutive cognitive assessments from 2004 through 2017, and at least one visit after the age of 60.

MEASUREMENTS

The primary outcome was longitudinal changes in global cognitive z-score. Secondary outcomes were changes in four cognitive domains: memory, attention/executive function, language, and visuospatial skills. Hospitalization characteristics analyzed included elective versus nonelective, medical versus surgical, critical care versus no critical care admission, and long versus short duration admissions.

RESULTS

Of 4,587 participants, 1,622 had 1 and more hospital admission. Before hospitalization, the average slope of the global z-score was -0.031 units/year. After hospitalization, the rate of annual global z-score accelerated by -0.051 (95% CI = -0.057, -0.045) units, P < .001, resulting in an estimated annual slope after the first hospitalization of -0.082. The accelerated decline was found in all four cognitive domains (memory, visuospatial, language, and executive, all P < .001). The acceleration of the decline in global z-score following hospitalization was greater for medical compared to surgical hospitalizations (slope change following hospitalization = -0.064 vs -0.034 for medical vs surgical, P < .001), and nonelective compared to elective admissions (slope change following hospitalization = -0.075 vs -0.037 for nonelective vs elective, P < .001). The acceleration of cognitive decline was not different for hospitalization with intensive care unit admission versus not.

CONCLUSIONS

Hospitalization of older adults is associated with accelerated decline of global and domain-specific cognitive domains, with the rate of decline dependent upon type of admission. The clinical impact of this accelerated decline will depend on the individual's baseline cognitive reserve and expected longevity.

Postoperative Neurocognitive Disorders in Cardiac Surgery: Investigating the Role of Intraoperative Hypotension. A Systematic Review

Perioperative neurocognitive disorders remain a challenging obstacle in patients after cardiac surgery, as they significantly contribute to postoperative morbidity and mortality. Identifying the modifiable risk factors and mechanisms for postoperative cognitive decline (POCD) and delirium (POD) would be an important step forward in preventing such adverse events and thus improving patients’ outcome. Intraoperative hypotension is frequently discussed as a potential risk factor for neurocognitive decline, due to its significant impact on blood flow and tissue perfusion, however the studies exploring its association with POCD and POD are very heterogeneous and present divergent results. This review demonstrates 13 studies found after structured systematic search strategy and discusses the possible relationship between intraoperative hypotension and postoperative neuropsychiatric dysfunction.

Postoperative Delirium is a Risk Factor of Poor Evolution Three Years After Cardiac Surgery: An Observational Cohort Study

Background

After cardiac surgery, postoperative delirium (POD) is common and is associated with long-term changes in cognitive function. Impact on health-related quality of life (QOL) and long-term dependence are not well known. This aim of this study is to evaluate the role of POD in poor evolution at three years after surgery including poor QOL and dependence and mortality.

Patients and Methods

We enrolled and followed 173 patients 60 years of age or older who were planning to undergo cardiac surgery with cardiopulmonary bypass. The primary composite outcome was death of any causes, or patients with either a loss of QOL (evaluated with of EuroQuol verbal 5D EQ5D less than 50), or a loss of two points on the instrumental activities of daily living occurring three years after surgery. POD was diagnosed with the use of Confusion Assessment Method. Multivariate logistic regression was performed.

Results

At three years, 74 patients (42.8%) had a poor evolution. Independent risk factors in poor patient evolution were sex (female gender; OR: 3.6; 95%CI: 1.45-8.7; p=0.006), metabolic status (diabetic patients; OR: 4; 95%CI: 1.6-10.2; p=0.002), Euroscore 2 (Euroscore 2 >1.5; OR: 5.2; 95%CI: 1.7-15.4; p=0.003) and POD (OR: 3.3; 95%CI 1.4-7.8; p=0.006). Coronary disease was protective (OR: 0.3; 95%CI: 0.14-0.71; p=0.006).

Conclusion

After cardiac surgery, POD significantly altered patient evolution and increased risk of dependence and loss of QOL.

Electroencephalographic Alpha and Delta Oscillation Dynamics in Response to Increasing Doses of Propofol

BACKGROUND

The electroencephalogram (EEG) may be useful for monitoring anesthetic depth and avoiding overdose. We aimed to characterize EEG-recorded brain oscillations during increasing depth of anesthesia in a real-life surgical scenario. We hypothesized that alpha power and coherency will diminish as propofol dose increases between loss of consciousness (LOC) and an EEG burst suppression (BS) pattern.

METHODS

This nonrandomized dose-response clinical trial with concurrent control included EEG monitoring in 16 patients receiving slowly increasing doses of propofol. We assessed 3 intraoperative EEG segments (LOC, middle-dose, and BS) with spectral analysis.

RESULTS

Alpha band power diminished with each step increase in propofol dose. Average alpha power and average delta power during the BS step (-1.4±3.8 and 6.2±3.1 dB, respectively) were significantly lower than during the LOC step (2.8±2.6; P=0.004 and 10.1±5.2 dB; P=0.03, respectively). Peak alpha power was significantly higher during the LOC (5.4±2.6 dB) compared with middle-dose (2.6±3.6; P=0.04) and BS (0.7±3.2; P=0.0002) steps. In addition, as propofol dose increased, alpha band coherence between the F7 and F8 electrodes decreased, whereas delta band coherence exhibited a biphasic response (initial increase between LOC and middle-dose steps and decrease between middle-dose and BS steps).

CONCLUSION

We report compelling data regarding EEG patterns associated with increases in propofol dose. This information may more accurately define "therapeutic windows" for anesthesia and provide insights into brain dynamics that are sequentially affected by increased anesthetic doses.

Postoperative delirium is associated with increased plasma neurofilament light

While delirium is associated with cognitive decline and dementia, there is limited evidence to support causality for this relationship. Clarification of how delirium may cause cognitive decline, perhaps through evidence of contemporaneous neuronal injury, would enhance plausibility for a causal relationship. Dose-dependence of neuronal injury with delirium severity would further enhance the biological plausibility for this relationship. We tested whether delirium is associated with neuronal injury in 114 surgical patients recruited to a prospective biomarker cohort study. Patients underwent perioperative testing for changes in neurofilament light, a neuronal injury biomarker, as well as a panel of 10 cytokines, with contemporaneous assessment of delirium severity and incidence. A subset of patients underwent preoperative MRI. Initially we confirmed prior reports that neurofilament light levels correlated with markers of neurodegeneration [hippocampal volume (ΔR2 = 0.129, P = 0.015)] and white matter changes including fractional anisotropy of white matter (ΔR2 = 0.417, P < 0.001) with similar effects on mean, axial and radial diffusivity) in our cohort and that surgery was associated with increasing neurofilament light from preoperative levels [mean difference (95% confidence interval, CI) = 0.240 (0.178, 0.301) log10 (pg/ml), P < 0.001], suggesting putative neuronal injury. Next, we tested the relationship with delirium. Neurofilament light rose more sharply in participants with delirium compared to non-sufferers [mean difference (95% CI) = 0.251 (0.136, 0.367) log10 (pg/ml), P < 0.001]. This relationship showed dose-dependence, such that neurofilament light rose proportionately to delirium severity (ΔR2 = 0.199, P < 0.001). Given that inflammation is considered an important driver of postoperative delirium, next we tested whether neurofilament light, as a potential marker of neurotoxicity, may contribute to the pathogenesis of delirium independent of inflammation. From a panel of 10 cytokines, the pro-inflammatory cytokine IL-8 exhibited a strong correlation with delirium severity (ΔR2 = 0.208, P < 0.001). Therefore, we tested whether the change in neurofilament light contributed to delirium severity independent of IL-8. Neurofilament light was independently associated with delirium severity after adjusting for the change in inflammation (ΔR2 = 0.040, P = 0.038). These data suggest delirium is associated with exaggerated increases in neurofilament light and that this putative neurotoxicity may contribute to the pathogenesis of delirium itself, independent of changes in inflammation.

The correlation of intraoperative hypotension and postoperative cognitive impairment: a meta-analysis of randomized controlled trials

BACKGROUND

There is no consensus on whether intraoperative hypotension is associated with postoperative cognitive impairment. Hence, we performed a meta-analysis to evaluate the correlation of intraoperative hypotension and the incidence of postoperative delirium (POD) or postoperative cognitive dysfunction (POCD).

METHODS

We searched PubMed, Embase, and Cochrane Library databases to find randomized controlled trials (RCTs) in which reported the relationship between intraoperative hypotension and POD or POCD. The retrieval time is up to January 2020, without language restrictions. Quality assessment of the eligible studies was conducted by two researchers independently with the Cochrane evaluation system.

RESULTS

We analyzed five eligible RCTs. Based on the relative mean arterial pressure (MAP), participants were divided into low-target and high-target groups. For the incidence of POD, there were two studies with 99 participants in the low-target group and 94 participants in the high-target pressure group. For the incidence of POCD, there were four studies involved 360 participants in the low-target group and 341 participants in the high-target group, with a study assessed both POD and POCD. No significant difference between the low-target and the high-target group was observed in the incidence of POD (RR = 3.30, 95% CI 0.80 to 13.54, P = 0.10), or POCD (RR = 1.26, 95% CI 0.76 to 2.08, P = 0.37). Furthermore, it also demonstrates that intraoperative hypotension prolonged the length of ICU stay, but did not increased the mortality, the length of hospital stay, and mechanical ventilation (MV) time.

CONCLUSIONS

There is no significant correlation between intraoperative hypotension and the incidence of POD or POCD.

Effects of PYRIN-containing Apaf1-like protein 1 on isoflurane-induced postoperative cognitive dysfunction in aged rats

Postoperative cognitive dysfunction (POCD) is a prevalent neurocognitive disorder following surgery and anesthesia, particularly in elderly patients. Isoflurane is a widely used anesthetic agent, which is associated with the development of POCD; however, the precise mechanisms remain unclear. In the present study, aged rats were exposed to 2% isoflurane to establish a POCD model. The expression of PYRIN-containing Apaf1-like protein 1 (PYPAF1) was knocked down using a lentivirus containing specific short hairpin RNA. Subsequently, the spatial learning ability of rats was assessed using the Morris water maze. In addition, mRNA and protein expression levels were detected using reverse transcription-quantitative PCR and western blot analysis, respectively. Immunofluorescence double staining was also used to determine the expression of PYPAF1 and Iba-1 in the hippocampus. Neural apoptosis was observed using TUNEL-NeuN double staining. The results revealed that isoflurane exposure impaired the spatial learning ability of rats, while PYPAF1 knockdown alleviated cognitive impairment. In addition, isoflurane exposure induced activation of the PYPAF1 inflammasome, as evidenced by elevated expression of PYPAF1 and apoptosis-associated speck-like protein containing a caspase recruitment domain, while silencing of PYPAF1 partially reversed this effect. Furthermore, isoflurane exposure promoted the activation of microglia and caspase-1, and the secretion of interleukin (IL)-1β and IL-18, all of which were alleviated following PYPAF1 silencing. Moreover, isoflurane exposure induced neuronal apoptosis, elevated the levels of Bax and cleaved caspase-3, and inhibited the expression of Bcl-2; all of these effects were partially abrogated following PYPAF1 silencing. In conclusion, the results of the present study indicated that PYPAF1 silencing partially abolished isoflurane-induced cognitive impairment, neuroinflammation and neuronal apoptosis. Therefore, PYPAF1 may be a potential therapeutic target for treatment of POCD.

Observational Study Examining the Association of Baseline Frailty and Postcardiac Surgery Delirium and Cognitive Change

BACKGROUND

Frailty is a geriatric syndrome thought to identify the most vulnerable older adults, and morbidity and mortality has been reported to be higher for frail patients after cardiac surgery compared to nonfrail patients. However, the cognitive consequences of frailty after cardiac surgery have not been well described. In this study, we examined the hypothesis that baseline frailty would be associated with postoperative delirium and cognitive change at 1 and 12 months after cardiac surgery.

METHODS

This study was nested in 2 trials, each of which was conducted by the same research team with identical measurement of exposures and outcomes. Before surgery, patients were assessed with the validated "Fried" frailty scale, which evaluates 5 domains (shrinking, weakness, exhaustion, low physical activity, and slowed walking speed) and classifies patients as nonfrail, prefrail, and frail. The primary outcome was postoperative delirium during hospitalization, which was assessed using the Confusion Assessment Method, Confusion Assessment Method for the Intensive Care Unit, and validated chart review. Neuropsychological testing was a secondary outcome and was generally performed within 2 weeks of surgery and then 4-6 weeks and 1 year after surgery, and the outcome of interest was change in composite Z-score of the test battery. Associations were analyzed using logistic and linear regression models, with adjustment for variables considered a priori (age, gender, race, education, and logistic European System for Cardiac Operative Risk Evaluation). Multiple imputation was used to account for missing data at the 12-month follow-up.

RESULTS

Data were available from 133 patients with baseline frailty assessments. Compared to nonfrail patients (13% delirium incidence), the incidence of delirium was higher in prefrail (48% delirium incidence; risk difference, 35%; 95% CI, 10%-51%) and frail patients (48% delirium incidence; risk difference, 35%; 95% CI, 7%-53%). In both univariable and multivariable models, the odds of delirium were significantly higher for prefrail (adjusted odds ratio, 6.43; 95% CI, 1.31-31.64; P = .02) and frail patients (adjusted odds ratio, 6.31; 95% CI, 1.18-33.74; P = .03) compared to nonfrail patients. The adjusted decline in composite cognitive Z-score was greater from baseline to 1 month only in frail patients compared to nonfrail patients. By 1 year after surgery, there were no differences in the association of baseline frailty with change in cognition.

CONCLUSIONS

Compared to nonfrail patients, both prefrail and frail patients were at higher risk for the primary outcome of delirium after cardiac surgery. Frail patients were also at higher risk for the secondary outcome of greater decline in cognition from baseline to 1 month, but not baseline to 1 year, after surgery.

Electric vagal nerve stimulation inhibits inflammation and improves early postoperation cognitive dysfunction in aged rats

BACKGROUND

This study aimed to evaluate effects of electric vagal nerve stimulation on early postoperation cognitive dysfunction in aged rats.

METHODS

A total of 33 male Sprague Dawley rats were selected and assigned randomly to three groups, control group (C, n = 10), splenectomy group (S, n = 10) and splenectomy+vagal nerve stimulation group (SV, n = 13). Behavior and memory of rats were evaluated by Open Field Test and Morris Water Maze. Levels of TNF-α, IL-6 and IL-10 in serum were measured by ELISA. The level of TNF-α protein in hippocampus was assessed by Western blotting. rt-PCR was used to detect mRNA expression of NF-κB in hippocampus.

RESULTS

During anesthesia/operation, vital life signs of rats were stable. In SV group, vagal nerve stimulation decreased heart rate lower than 10% of basic level and kept it at a stable range by regulating stimulation intensity. After stimulation stop, heart rate returned to the basic level again. This indicated that the model of vagal nerve stimulation was successful. Serum levels of TNF-α and IL-6 increased by the operation/anesthesia, but they decreased with vagal nerve stimulation (all P < 0.05). TNF-α protein and mRNA expression of NF-κB in hippocampus were also eliminated by vagal nerve stimulation compared to S group (P < 0.05). Results of Morris Water Maze showed escape latency of postoperation in S group was significantly longer than C group (P < 0.05), and times of crossing platform in S group was lower than that of C group (P < 0.05). Although escape latency of postopration in SV group was shorter than that of S group, there was no significant difference between two groups. Meanwhile there were no significant differences of behavior test in Open Field test between three groups, although vagal nerve stimulation improved partly active explore behavior compared to S group.

CONCLUSION

The inflammation caused by operation and general anesthesia was an important reason of early postoperation cognitive dysfunction, and electric vagal nerve stimulation could inhibit the inflammation. Meanwhile, vagal nerve stimulation could ameliorate early postoperation cognitive dysfunction partly, but its protective effects were not enough and should be studied and improved in future.

Association between major surgical admissions and the cognitive trajectory: 19 year follow-up of Whitehall II cohort study

OBJECTIVE

To quantify the association between major surgery and the age related cognitive trajectory.

DESIGN

Prospective longitudinal cohort study.

SETTING

United Kingdom.

PARTICIPANTS

7532 adults with as many as five cognitive assessments between 1997 and 2016 in the Whitehall II study, with linkage to hospital episode statistics. Exposures of interest included any major hospital admission, defined as requiring more than one overnight stay during follow-up.

MAIN OUTCOMES MEASURES

The primary outcome was the global cognitive score established from a battery of cognitive tests encompassing reasoning, memory, and phonemic and semantic fluency. Bayesian linear mixed effects models were used to calculate the change in the age related cognitive trajectory after hospital admission. The odds of substantial cognitive decline induced by surgery defined as more than 1.96 standard deviations from a predicted trajectory (based on the first three cognitive waves of data) was also calculated.

RESULTS

After accounting for the age related cognitive trajectory, major surgery was associated with a small additional cognitive decline, equivalent on average to less than five months of aging (95% credible interval 0.01 to 0.73 years). In comparison, admissions for medical conditions and stroke were associated with 1.4 (1.0 to 1.8) and 13 (9.6 to 16) years of aging, respectively. Substantial cognitive decline occurred in 2.5% of participants with no admissions, 5.5% of surgical admissions, and 12.7% of medical admissions. Compared with participants with no major hospital admissions, those with surgical or medical events were more likely to have substantial decline from their predicted trajectory (surgical admissions odds ratio 2.3, 95% credible interval 1.4 to 3.9; medical admissions 6.2, 3.4 to 11.0).

CONCLUSIONS

Major surgery is associated with a small, long term change in the average cognitive trajectory that is less profound than for major medical admissions. The odds of substantial cognitive decline after surgery was about doubled, though lower than for medical admissions. During informed consent, this information should be weighed against the potential health benefits of surgery.

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.

Postoperative cognitive decline: the nurse's role in identifying this underestimated and misinterpreted condition

BACKGROUND

postoperative cognitive changes can increase morbidity and mortality, demand for postoperative care and social and health costs, and can lead to dementia.

AIM

this article discusses perioperative variables that can be used to identify patients who are more vulnerable to experiencing cognitive decline after surgery. It also highlights some screening tools that could be useful for early detection and for planning nursing care.

METHOD

a literature search was conducted using the Medline, CINAHL, PsychINFO and Cochrane Library databases from 2010 to 2018. Google Scholar was also consulted. The reference lists of relevant articles covering postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) were reviewed for further relevant papers.

CONCLUSION

assessment and evaluation of a patient's cognitive resources before and after surgery can lead to clinical interventions to support the person's coping mechanisms; health professionals can reduce the short- and long-term effects of cognitive decline. Screening tools could be used as part of a strategy to minimise postoperative cognitive changes.