Dementia risk amongst older adults with hip fracture receiving general anaesthesia or regional anaesthesia: a propensity-score-matched population-based cohort study

Acute changes in hippocampal metabolism after anesthesia and surgery: Implications for perioperative neurocognitive disorder

BACKGROUND

The risk of developing dementia is higher in individuals who suffer from perioperative neurocognitive disorder (PND), including postoperative cognitive dysfunction (POCD) and delirium. Recent studies have indicated correlations between anesthesia, surgery and PND. Acute metabolic changes induced by anesthesia and surgery may be related to cognitive impairments. Despite a paucity of research on acute metabolic changes in the hippocampus during surgery, there are conflicting about specific metabolites.

METHODS

We developed a mouse model of cognitive impairment induced by isoflurane anesthesia and unilateral nephrectomy. Cognition was evaluated by Y maze and fear conditioning test (FCT). The hippocampus was harvested after the surgery. LC-MS (liquid chromatography-mass spectrometry) was performed. The differential metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were analyzed.

RESULTS

Anesthesia and surgery exposure induced cognition decline. A total of 49 metabolites were significantly up-regulated and 122 down-regulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway of the metabolites identified purine, glutathione, nicotinate and nicotinamide metabolism. Metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were identified including nicotinamide adenine dinucleotide (NAD), 1-Methylnicotinamide, propionic acid, histidine, adenosine, and guanosine cyclic monophosphate. Some metabolites exhibited a consistent change trend in the hippocampus of aging mice.

CONCLUSIONS

The study indicates that anesthesia and surgery can induce acute alterations in hippocampal metabolomics, including metabolites involved in lipid, amino acid, nucleotide, and carbohydrate metabolism. These metabolites may play a role in modulating PND through the regulation of neuroinflammation, oxidative stress, blood-brain barrier (BBB) permeability.

General anesthesia is not associated with dementia in older adults with osteoarthritis for hip/knee replacements, a national population-based nested case-control study

BACKGROUND

Dementia is a prevalent neurological condition, yet the relationship between dementia and general anesthesia remains uncertain. The study aimed to explore the association between general anesthesia and dementia using a nationwide population-based database.

METHODS

The study extracted data from Taiwan's national health insurance, which encompassed the records of one million insured residents. A total of 59,817 patients aged 65 years and above, diagnosed with osteoarthritis between 2002 and 2010, were included. Among these patients, 3277 individuals with an initial diagnosis of dementia between 2004 and 2013 were matched with non-dementia patients based on age, gender, and the date of osteoarthritis diagnosis. Following a 1:2 random matching, the case group included 2171 patients with dementia, while the control group consisted of 4342 patients without dementia. The data was analyzed using conditional and unconditional logistic regressions.

RESULTS

No significant differences in the odds of dementia were found between individuals exposed to general and regional anesthesia during hip/knee replacement surgeries (OR = 1.11; 95%CI: 0.73-1.70), after adjusting for age, sex, and co-morbidities. Similarly, there were no significant differences in the odds of dementia based on different durations of anesthesia exposure (General: <2 h: OR = 0.91, 95%CI = 0.43-1.92; 2-4 h: OR = 1.21, 95%CI = 0.82-1.79; >4 h: OR = 0.39, 95%CI = 0.15-1.01; compared to no exposure. Regional: <2 h: OR = 1.18, 95%CI = 0.85-1.62; 2-4 h: OR = 0.9, 95%CI = 0.64-1.27; >4 h: OR = 0.55, 95%CI = 0.15-1.96; compared to no exposure). Likewise, no significant differences were observed in the odds of dementia based on the number of replacement surgeries (twice: OR = 0.74, 95%CI = 0.44-1.23, compared to once).

CONCLUSION

Neither general anesthesia nor regional anesthesia in hip/knee surgery was associated with dementia. Different numbers and durations of anesthesia exposure showed no significant differences in the odds for dementia.

Comparison of regional vs. general anesthesia on the risk of dementia: a systematic review and meta-analysis

Background

Dementia is a gradual and ongoing cognitive decline due to damage to nerve cells in the brain. This meta-analysis aimed to assess the potential relationship between regional anesthesia (RA) and the risk of dementia.

Methods

Electronic databases including Embase, Medline, Google Scholar, and Cochrane Library were searched for studies investigating the association between RA and dementia risk from inception to March 2022. The primary outcome was the risk of dementia in patients who underwent RA (RA group) and those who received general anesthesia (GA group). Secondary outcomes included identifying other potential risk factors for dementia and comparing dementia risk between individuals receiving RA and those not receiving surgery/anesthesia (placebo group).

Results

Eight cohort studies published between 2014 and 2023 were included in this analysis. A meta-analysis of the available data demonstrated no differences in baseline characteristics and morbidities (i.e., age, male proportion, hypertension, diabetes, depression, and severe comorbidities) between the RA and GA groups (all p > 0.05). Initial analysis revealed that the risk of dementia was higher in the GA group than in the RA group (HR = 1.81, 95% CI = 1.29-2.55, p = 0.007, I 2 = 99%, five studies). However, when a study featuring a relatively younger population was excluded from the sensitivity analysis, the results showed a similar risk of dementia (HR, 1.17; p = 0.13) between the GA and RA groups. The pooled results revealed no difference in dementia risk between the RA and placebo groups (HR = 1.2, 95% CI = 0.69-2.07, p = 0.52, I 2 = 68%, three studies). Sensitivity analysis revealed that the evidence was not stable, suggesting that limited datasets precluded strong conclusions on this outcome. Anxiety, stroke history, hypertension, diabetes, hyperlipidemia, and diabetes are potential predictors of dementia.

Conclusion

Our results emphasize that, while RA could be protective against dementia risk compared to GA, the association between the type of anesthesia and dementia risk might vary among different age groups. Owing to the significant prevalence of dementia among older people and their surgical needs, further investigations are warranted to clarify the association between dementia risk and regional anesthesia.Systematic review registration: https://www.crd.york.ac.uk/prospero/, CRD42023411324.

Sevoflurane-induced overexpression of extrasynaptic α5-GABAAR via the RhoA/ROCK2 pathway impairs cognitive function in aged mice

Perioperative neurocognitive disorder (PND) is a serious neurologic complication in aged patients and might be associated with sevoflurane exposure. However, the specific pathogenesis is still unclear. The distribution of α5-GABAAR, a γ-aminobutyric acid type A receptor (GABAAR) subtype, at extrasynaptic sites is influenced by the anchor protein radixin, whose phosphorylation is regulated via the RhoA/ROCK2 signaling pathway and plays a crucial role in cognition. However, whether sevoflurane affects the ability of radixin phosphorylation to alter extrasynaptic receptor expression is unknown. Aged mice were exposed to sevoflurane to induce cognitive impairment. Both total proteins and membrane proteins were extracted for analysis. Cognitive function was evaluated using the Morris water maze and fear conditioning test. Western blotting was used to determine the expression of ROCK2 and the phosphorylation of radixin. Furthermore, the colocalization of p-radixin and α5-GABAAR was observed. To inhibit ROCK2 activity, either an adeno-associated virus (AAV) or fasudil hydrochloride was administered. Aged mice treated with sevoflurane exhibited significant cognitive impairment accompanied by increased membrane expression of α5-GABAAR. Moreover, the colocalization of α5-GABAAR and p-radixin increased after treatment with sevoflurane, and this change was accompanied by an increase in ROCK2 expression and radixin phosphorylation. Notably, inhibiting the RhoA/ROCK2 pathway significantly decreased the distribution of extrasynaptic α5-GABAAR and improved cognitive function. Sevoflurane activates the RhoA/ROCK2 pathway and increases the phosphorylation of radixin. Excess α5-GABAAR is anchored to extrasynaptic sites and impairs cognitive ability in aged mice. Fasudil hydrochloride administration improves cognitive function.

Dose-Dependent Effect of Aspirin Use in Reducing Diabetes-Associated Dementia Risk Among Elderly Patients With Type 2 Diabetes Mellitus

OBJECTIVE

This study investigated the association between aspirin use and diabetes-associated dementia in older patients with type 2 diabetes mellitus (T2DM), assessing aspirin's potential protective effects, intensity of use, and dose-dependency against dementia.

DESIGN

A cohort study evaluating the dose-dependent protective impact of aspirin against dementia in a population-based sample.

SETTING AND PARTICIPANTS

Older patients with T2DM (≥60 years), comparing aspirin users with nonusers.

METHODS

Used a time-varying Cox hazards model to assess dementia incidence.

RESULTS

Older aspirin users exhibited a significant reduction in dementia risk (adjusted hazard ratio [aHR], 0.44; 95% CI, 0.41-0.46). The lowest aHRs for dementia were observed at a daily intensity of 0.91 defined daily doses (DDDs), and higher daily dosages (>0.91 DDD) showed gradually increasing aHRs (although still <1). Analysis of cumulative DDD revealed a dose-response relationship, with progressively lower aHRs across quartiles (0.16, 0.42, 0.57, and 0.63 for quartiles 4, 3, 2, and 1, respectively) compared with never aspirin users (P for trend < .0001).

CONCLUSIONS AND IMPLICATIONS

Aspirin use in older patients with T2DM significantly reduces dementia risk. The optimal daily intensity of aspirin use (0.91 DDD) is associated with the lowest aHR for dementia. These findings suggest a dose-dependent relationship, supporting the potential benefits of higher cumulative dosages of aspirin in reducing dementia risk in this population.

Metformin in elderly type 2 diabetes mellitus: dose-dependent dementia risk reduction

This study aimed to investigate the controversial association between metformin use and diabetes-associated dementia in elderly patients with type 2 diabetes mellitus (T2DM) and evaluate the potential protective effects of metformin, as well as its intensity of use and dose-dependency, against dementia in this population. The study used a time-dependent Cox hazards model to evaluate the effect of metformin use on the incidence of dementia. The case group included elderly patients with T2DM (≥60 years old) who received metformin, while the control group consisted of elderly patients with T2DM who did not receive metformin during the follow-up period. Our analysis revealed a significant reduction in the risk of dementia among elderly individuals using metformin, with an adjusted hazard ratio of 0.34 (95% confidence interval: 0.33 to 0.36). Notably, metformin users with a daily intensity of 1 defined daily dose (DDD) or higher had a lower risk of dementia, with an adjusted hazard ratio (95% confidence interval) of 0.46 (0.22 to 0.6), compared to those with a daily intensity of <1 DDD. Additionally, the analysis of cumulative DDDs of metformin showed a dose-response relationship, with progressively lower adjusted hazard ratio across quartiles (0.15, 0.21, 0.28, and 0.53 for quartiles 4, 3, 2 and 1, respectively), compared to never metformin users (P for trend < 0.0001). Metformin use in elderly patients with T2DM is significantly associated with a substantial reduction in the risk of dementia. Notably, the protective effect of metformin demonstrates a dose-dependent relationship, with higher daily and cumulative dosages of metformin showing a greater risk reduction.

Adapted diabetes complications severity index predicts dementia risk in ageing type 2 diabetes mellitus patients

This study investigated the link between the adapted diabetes complication severity index at the time of type 2 diabetes mellitus diagnosis and diabetes-induced dementia risk in elderly patients. Elderly type 2 diabetes mellitus patients (age ≥ 60) were matched using propensity score matching. Cox regression was used to determine dementia hazard ratios; Kaplan-Meier method to assess cumulative incidence. The cohort included 256 214 elderly type 2 diabetes mellitus patients. Adapted diabetes complication severity index ≥ 1 showed higher dementia risk (adjusted hazard ratio: 1.30; 95% confidence interval: 1.27-1.34), increasing by 1.17-fold per adapted diabetes complication severity index point. Dementia risk rose progressively across adapted diabetes complication severity index scores (P < 0.0001). Higher adapted diabetes complication severity index scores at the time of type 2 diabetes mellitus diagnosis elevated dementia risk in elderly patients. Adapted diabetes complication severity index ≥ 1 is linked to increased dementia risk. Adapted diabetes complication severity index evaluation at the time of type 2 diabetes mellitus diagnosis could predict risk, aiding early interventions. Effective diabetes management is crucial for reducing dementia risk in this population.

Reducing the carbon footprint of general anaesthesia: a comparison of total intravenous anaesthesia vs. a mixed anaesthetic strategy in 47,157 adult patients

Global warming is a major public health concern. Volatile anaesthetics are greenhouse gases that increase the carbon footprint of healthcare. Modelling studies indicate that total intravenous anaesthesia is less carbon intensive than volatile anaesthesia, with equivalent quality of care. In this observational study, we aimed to apply the findings of previous modelling studies to compare the carbon footprint per general anaesthetic of an exclusive TIVA strategy vs. a mixed TIVA-volatile strategy. This comparative retrospective study was conducted over 2 years in two French hospitals, one using total intravenous anaesthesia only and one using a mixed strategy including both intravenous and inhalation anaesthetic techniques. Based on pharmacy procurement records, the quantity of anaesthetic sedative drugs was converted to carbon dioxide equivalents. The primary outcome was the difference in carbon footprint of hypnotic drugs per intervention between the two strategies. From 1 January 2021 to 31 December 2022, 25,137 patients received general anaesthesia in the hospital using the total intravenous anaesthesia strategy and 22,020 in the hospital using the mixed strategy. The carbon dioxide equivalent footprint of hypnotic drugs per intervention in the hospital using the total intravenous anaesthesia strategy was 20 times lower than in the hospital using the mixed strategy (emissions of 2.42 kg vs. 48.85 kg carbon dioxide equivalent per intervention, respectively). The total intravenous anaesthesia strategy significantly reduces the carbon footprint of hypnotic drugs in general anaesthesia in adult patients compared with a mixed strategy. Further research is warranted to assess the risk-benefit ratio of the widespread adoption of total intravenous anaesthesia.

Protective Effects Against Dementia Undergo Different Statin Type, Intensity, and Cumulative Dose in Older Adult Type 2 Diabetes Mellitus Patients

OBJECTIVES

This study investigated the relationship between statin use and dementia risk in older adults with type 2 diabetes (T2DM). It also assessed the impact of various statin types, dosage intensity, and cumulative doses on dementia risk.

DESIGN

Employing the inverse probability of treatment weighting (IPTW) Cox hazards model, this research explored the influence of statin utilization on dementia incidence.

SETTING AND PARTICIPANTS

The study included older adult T2DM patients aged 60 years or older who received statins (case group) and those who did not (control group) during the follow-up period.

METHODS

The IPTW Cox hazards model quantified the association between statin use and dementia incidence. Subgroup analyses investigated different statin types, usage intensity, and cumulative dose-dependent relationships with dementia risk, measured by adjusted hazard ratios (aHRs) with corresponding 95% CIs.

RESULTS

Statin users experienced a significant reduction in dementia risk (aHR: 0.47, 95% CI: 0.46-0.48). Subgroup analysis using IPTW Cox regression revealed varying dementia incidence reductions among users of different statin types, with aHRs (95% CIs) ranging from 0.09 to 0.69. Multivariate analyses unveiled a dose-dependent relationship, showing reduced dementia incidence based on cumulative defined daily doses (cDDDs) per year. The corresponding aHRs (95% CIs) were 0.20 to 0.72 across quartiles 4 to 1 of cDDD-years, with a significant trend (P < .001). The optimal daily statin use was 0.88 defined daily doses (DDDs), associated with the lowest dementia risk.

CONCLUSIONS AND IMPLICATIONS

Statins significantly reduced dementia risk in older adult T2DM patients. Higher cumulative defined daily doses (cDDD-years) were linked to more substantial risk reductions. This research underscores the clinical benefits of statin use in preventing dementia in this population and calls for further investigation into the underlying mechanisms. It also raises the possibility of influencing policy decisions to manage dementia risk in this vulnerable group.

Improved postoperative outcomes in pediatric major surgery: evidence from hospital volume analysis

This study aimed to examine the association between hospital volume and postoperative outcomes in pediatric major surgery using a nationwide database. The study included pediatric patients who underwent first major elective inpatient surgery and hospitalization for more than 1 day. The results showed no significant difference in the risk of 30-day postoperative mortality based on hospital volume. However, patients in the middle- and high-volume groups had significantly lower rates of 30-day major complications, particularly deep wound infection. In terms of 90-day postoperative outcomes, patients in the high-volume group had a significantly lower risk of mortality and lower rates of major complications, particularly deep wound infection, pneumonia, and septicemia.  Conclusions: The study suggests that pediatric patients undergoing major surgery in high and middle-volume groups have better outcomes in terms of major complications compared to the low-volume group. What is Known: • Limited evidence exists on the connection between hospital volume and pediatric surgery outcomes. What is New: • A Taiwan-based study, using national data, found that high and middle hospital-volume groups experienced significantly lower rates of major complications within 30 and 90 days after surgery. • High-volume hospitals demonstrated a substantial decrease in the risk of 90-day postoperative mortality. • The study underscores the importance of specialized pediatric surgical centers and advocates for clear guidelines for hospital selection, potentially improving outcomes and informing future health policies.

Early childhood general anesthesia and risk of Attention Deficit Hyperactivity Disorder

BACKGROUND

The relationship between early childhood exposure to general anesthesia (GA) and the risk of developing Attention Deficit Hyperactivity Disorder (ADHD) is still uncertain and previous studies have presented conflicting results. This population-based cohort study aimed to investigate the potential relationship between GA exposure and ADHD risk using propensity score matching (PSM) in a large sample size.

METHODS

The study included 15,072 children aged 0-3 years who received GA and were hospitalized for more than 1 day in Taiwan from 2004 to 2014. The nonexposed group was randomly selected through 1:1 PSM from the Taiwan Maternal and Child Health Database (TMCHD). The primary objectives of this study were to determine the incidence rates (IR) and incidence rate ratios (IRR) of ADHD in the two cohorts, employing Poisson regression models.

RESULTS

The GA group and non-GA group each comprised 7,536 patients. The IR of ADHD was higher in the GA group (122.45 per 10,000 person-years) than in the non-GA group (64.15 per 10,000 person-years), and the IRR of ADHD in the GA group was 1.39 (95% CI: 1.26, 1.55). The study found that the number of times of exposure to GA, duration of exposure, male gender, and central nervous system surgery were significant risk factors for ADHD in the future.

CONCLUSIONS

This study's findings suggest that there is a significant correlation between early childhood exposure to GA and the risk of developing ADHD, and GA may be an important risk factor for ADHD in children undergoing surgery. The study also identified several risk factors for ADHD, including the number of times of exposure to GA, duration of exposure, male gender, and central nervous system surgery.

Sarcopenia and diabetes-induced dementia risk

This study aimed to investigate whether sarcopenia independently increases the risk of diabetes-induced dementia in elderly individuals diagnosed with type 2 diabetes mellitus. The study cohort consisted of a large sample of elderly individuals aged 60 years and above, who were diagnosed with type 2 diabetes mellitus between 2008 and 2018. To minimize potential bias and achieve covariate balance between the sarcopenia and non-sarcopenia groups, we employed propensity score matching. Various statistical analyses, including Cox regression models to assess dementia risk and associations, competing risk analysis to account for mortality and Poisson regression analysis for incidence rates, were used. Before propensity score matching, the study included 406 573 elderly type 2 diabetes mellitus patients, with 20 674 in the sarcopenia group. Following propensity score matching, the analysis included a total of 41 294 individuals, with 20 647 in the sarcopenia group and 20 647 in the non-sarcopenia group. Prior to propensity score matching, elderly type 2 diabetes mellitus patients with sarcopenia exhibited a significantly higher risk of dementia (adjusted hazard ratio: 1.12, 95% confidence interval: 1.07-1.17). After propensity score matching, the risk remained significant (adjusted hazard ratio: 1.14, 95% confidence interval: 1.07-1.21). Incidence rates of dementia were notably higher in the sarcopenia group both before and after propensity score matching, underscoring the importance of sarcopenia as an independent risk factor. Our study highlights sarcopenia as an independent risk factor for diabetes-induced dementia in elderly type 2 diabetes mellitus patients. Advanced age, female gender, lower income levels, rural residency, higher adapted diabetes complication severity index and Charlson Comorbidity Index scores and various comorbidities were associated with increased dementia risk. Notably, the use of statins was linked to a reduced risk of dementia. This research underscores the need to identify and address modifiable risk factors for dementia in elderly type 2 diabetes mellitus patients, offering valuable insights for targeted interventions and healthcare policies.

Comparison of oxygen reserve index according to the remimazolam or dexmedetomidine for intraoperative sedation under regional anesthesia-A single-blind randomized controlled trial

Introduction

We aimed to evaluate the difference in intraoperative oxygen reserve index (ORi) between the sedatives remimazolam (RMMZ) and dexmedetomidine (DEX).

Methods

Seventy-eight adult patients scheduled for sedation under regional anesthesia were randomly assigned to either the DEX (n = 39) or RMMZ (n = 39) group. The primary outcome was the difference in perioperative ORi between the groups. The secondary outcomes included respiratory depression, hypo- or hypertension, heart rate (HR), blood pressure, respiratory rate and postoperative outcomes. Additionally, the number of patients who experienced a decrease in intraoperative ORi to < 50% and the associated factors were analyzed.

Results

The ORi was significantly higher in the RMMZ group at 15 min after sedation maintenance. There were no significant differences in respiratory depression between the two groups. The intraoperative HR was significantly higher in the RMMZ group after the induction of sedation, 15 min after sedation maintenance, and at the end of surgery. No other results were significantly different between the two groups. The incidence of a decrease in intraoperative ORi to < 50% was significantly higher in the DEX group. Factors associated with a decrease in the intraoperative ORi to < 50% were diabetes mellitus, low baseline peripheral oxygen saturation (SpO2), and DEX use. In the receiver operating characteristic curve analysis for a decrease in the intraoperative ORi to < 50%, the cutoff baseline SpO2 was 97%.

Conclusion

RMMZ is recommended as a sedative for patients with a low baseline SpO2 and intraoperative bradycardia. Further studies should be conducted to establish the criteria for a significant ORi reduction.

Sublobar resection reduces the risk of postoperative cognitive dysfunction compared with lobectomy

OBJECTIVES

Sublobar resection, including wedge resection and segmentectomy, is non-inferior to lobectomy in early-stage non-small cell lung cancer treatment. We aimed to compare the risk of postoperative cognitive dysfunction (POCD) between sublobar resection and lobectomy.

METHODS

We conducted a prospective cohort study. Patients with sublobar resection or lobectomy were divided into the sublobar group or the lobar group, respectively. Cognition was assessed before and after surgery with Montreal Cognitive Assessment and Minimum Mental State Examination tests. POCD is defined as Z score of Montreal Cognitive Assessment change ≤-1.96. Propensity score matching (PSM) was performed to make demographics well-balanced between the 2 groups.

RESULTS

A total of 335 patients were enrolled. Both the postoperative 1-day POCD rate (sublobar 5.5% vs lobar 18.2%, P < 0.001) and the postoperative 1-month POCD rate (sublobar 7.9% vs lobar 21.8%, P < 0.001) were significantly lower in the sublobar group compared with lobar group, with demographics unbalanced between the 2 groups. In the 133 demographics-matched pairs obtained by PSM, both the postoperative 1-day POCD rate (sublobar 5.3% vs lobar 17.3%, P = 0.005) and the postoperative 1-month POCD rate (sublobar 8.3% vs lobar 18.8%, P = 0.018) remained significantly lower in the sublobar group than in the lobar group. The incidences of postoperative 1-day (P = 0.109) and postoperative 1-month (P = 0.026) Minimum Mental State Examination abnormity were also lower in the sublobar group than in the lobar group but only the latter was with statistical significance after PSM.

CONCLUSIONS

Sublobar resection has an advantage over lobectomy in preventing POCD. Our findings might be a reference for selecting the most suitable type of resection for non-small-cell lung cancer patients.

Update on Perioperative Delirium

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