Postoperative kognitive Dysfunktion: Inzidenz und Prophylaxe

The association of pre-operative biomarkers of endothelial dysfunction with the risk of post-operative neurocognitive disorders: results from the BioCog study

INTRODUCTION

Endothelial dysfunction (ED) promotes the development of atherosclerosis, and studies suggest an association with age-related neurocognitive disorders. It is currently unclear whether ED is also associated with the risk of perioperative neurocognitive disorders.

METHOD

We included 788 participants aged ≥ 65 years of the BioCog study. Patients were scheduled to undergo elective surgery with expected duration > 60 min. Blood was collected before surgery for measurement of 5 biomarkers of ED: asymmetric and symmetric dimethylarginine (ADMA; SDMA), intercellular and vascular adhesion molecule (ICAM-1, VCAM-1), and von Willebrand factor (vWF). Patients were monitored for the occurrence of postoperative delirium (POD) daily until the 7th postoperative day. 537 (68.1%) patients returned for a 3-month follow-up. Post-operative cognitive dysfunction (POCD) was defined from the change in results on a battery of 6 neuropsychological tests between baseline and 3 months, compared to the change in results of a control group during the 3-month interval. The associations of each of the 5 ED biomarkers with POD and POCD respectively were determined using multiple logistic regression analyses with adjustment for age, sex, surgery type, pre-morbid IQ, body mass index, hypertension, diabetes, HbA1C, triglyceride, total and HDL cholesterol.

RESULTS

19.8% of 788 patients developed POD; 10.1% of 537 patients had POCD at 3 months. Concentrations of ED biomarkers were not significantly associated with a POD. A higher VCAM-1 concentration was associated with a reduced POCD risk (adjusted odds ratio 0.55; 95% CI: 0.35-0.86). No further statistically significant results were found.

CONCLUSION

Pre-operative concentrations of ED biomarkers were not associated with POD risk. We unexpectedly found higher VCAM-1 to be associated with a reduced POCD risk. Further studies are needed to evaluate these findings.

Emerging Insights into Postoperative Neurocognitive Disorders: The Role of Signaling Across the Gut-Brain Axis

The pathophysiological regulatory mechanisms in postoperative neurocognitive disorders (PNCDs) are intricately complex. Currently, the pathogenesis of PNCDs has not been fully elucidated. The mechanism involved may include a variety of factors, such as neuroinflammation, oxidative stress, and neuroendocrine dysregulation. Research into the gut microbiota-induced regulations on brain functions is increasingly becoming a focal point of exploration. Emerging evidence has shown that intestinal bacteria may play an essential role in maintaining the homeostasis of various physiological systems and regulating disease occurrence. Recent studies have confirmed the association of the gut-brain axis with central nervous system diseases. However, the regulatory effects of this axis in the pathogenesis of PNCDs remain unclear. Therefore, this paper intends to review the bidirectional signaling and mechanism of the gut-brain axis in PNCDs, summarize the latest research progress, and discuss the possible mechanism of intestinal bacteria affecting nervous system diseases. This review is aimed at providing a scientific reference for predicting the clinical risk of PNCD patients and identifying early diagnostic markers and prevention targets.

Two-lung ventilation with artificial pneumothorax on cerebral desaturation and early postoperative cognitive outcome: a randomized controlled trial

BACKGROUND

The effect of two lung ventilation (TLV) with carbon dioxide artificial pneumothorax on cerebral desaturation and postoperative neurocognitive changes in elderly patients undergoing elective minimally invasive esophagectomy (MIE) is unclear.

OBJECTIVES

The first aim of this study was to compare the effect of TLV and one lung ventilation (OLV) on cerebral desaturation. The second aim was to assess changes in early postoperative cognitive outcomes of two ventilation methods.

METHODS

This prospective, randomized, controlled trial enrolled patients 65 and older scheduled for MIE. Patients were randomly assigned (1:1) to TLV group or OLV group. The primary outcome was the incidence of cerebral desaturation events (CDE). Secondary outcomes were the cumulative area under the curve of desaturation for decreases in regional cerebral oxygen saturation (rSO2) values below 20% relative to the baseline value (AUC.20) and the incidence of delayed neurocognitive recovery.

RESULTS

Fifty-six patients were recruited between November 2019 and August 2020. TLV group had a lower incidence of CDE than OLV group [3 (10.71%) vs. 13 (48.14%), P = 0.002]. TLV group had a lower AUC.20 [0 (0-35.86) % min vs. 0 (0-0) % min, P = 0.007], and the incidence of delayed neurocognitive recovery [2 (7.4%) vs. 11 (40.7%), P = 0.009] than OLV group. Predictors of delayed neurocognitive recovery on postoperative day 7 were age (OR 1.676, 95% CI 1.122 to 2.505, P = 0.006) and AUC.20 (OR 1.059, 95% CI 1.025 to 1.094, P < 0.001).

CONCLUSION

Compared to OLV, TLV had a lower incidence of CDE and delayed neurocognitive recovery in elderly patients undergoing MIE. The method of TLV combined with carbon dioxide artificial pneumothorax may be an option for these elderly patients. Chinese Clinical Trial Registry (identifier: ChiCTR1900027454).

ABCA7 rs3764650 Polymorphism is Associated with Delayed Neurocognitive Recovery

Background

Several studies have shown that ATP-binding cassette transporter A7 (ABCA7) gene variation is associated with cognitive impairment. This study was aimed to investigate the relationship between ABCA7 rs3764650 polymorphism and perioperative neurocognitive disorder (pNCD).

Methods

A total of 132 elderly patients aged 65 and over who underwent elective non-cardiac surgery were enrolled in the study, while 28 healthy volunteers matching age and sex were recruited as the control group. A battery of neuropsychological tests was conducted 1 day before, 7 days, and 3 months after surgeries. Delayed neurocognitive recovery (dNCR) and postoperative mild or major neurocognitive disorder (POCD) were determined using the Z value method. The venous blood sample of the surgical patients was taken before the operation. Genotyping of rs3764650 was performed using polymerase chain reaction amplification and restriction fragment length polymorphism analysis.

Results

The incidences of dNCR and POCD were 29.7% and 16.8% at 7 days and 3 months after surgery, respectively. The G allele frequency and GG frequency of dNCR patients were significantly higher than that of non-dNCR patients (43.3% vs 28.2%, P=0.035; 23.3% vs 4.2%, P=0.013, respectively) at 7 days following surgery. No significant differences in ABCA7 alleles between POCD and non-POCD patients were observed 3 months postoperatively.

Conclusion

ABCA7 rs3764650 gene polymorphism is associated with dNCR and GG genotype might be a predisposing factor for postoperative cognitive impairment in Chinese Han elderly populations.

Repeated Preoperative Intranasal Administration of Insulin Decreases the Incidence of Postoperative Delirium in Elderly Patients Undergoing Laparoscopic Radical Gastrointestinal Surgery: A Randomized, Placebo-Controlled, Double-Blinded Clinical Study

STUDY OBJECTIVES

This study aimed to investigate the effects of repeated preoperative intranasal administration of insulin on the incidence of postoperative delirium (POD) and the levels of serum pro-inflammatory markers in elderly patients undergoing laparoscopic radical gastrointestinal surgery.

DESIGN

Prospective, randomized, double-blinded, placebo-controlled clinical study.

SETTING

General Hospital of Western Theater Command from August 2019 to December 2019.

PATIENTS

Ninety elderly patients underwent laparoscopic radical gastrointestinal tumor resections under general anesthesia.

INTERVENTIONS

Patients were randomly divided into a control group (0.5 mL saline administered intranasally) or an insulin group (20 U/0.5 mL insulin administered intranasally) for 2 days prior to surgery, with 45 patients in each group.

MEASUREMENTS

The incidence of delirium was measured at postoperative day 1 (T2), day 3 (T3), and day 5 (T4) using the Confusion Assessment Method for the intensive care unit (CAM-ICU). Plasma levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were measured at T0 (before insulin or saline administration), T1 (at the end of surgery), T2, T3, and T4 by enzyme-linked immunosorbent assay.

MAIN RESULTS

Compared with the control group, the insulin group demonstrated a decreased POD incidence (12.5% vs. 47.5%, p = 0.001) within 5 days after surgery. The incidence of POD was significantly lower in the Ins group than in the Con group at T2 (12.5% vs. 32.5%, p = 0.032) and at T3 (2.5% vs. 20%, p = 0.034). The incidence of POD decreased in both groups over time and was similar at T4 (0% vs 10%, p = 0.116). Compared with the baseline value at T0, serum TNF-α, IL-6 and IL-1β concentrations increased significantly at T1-4 (p <0.05). Compared with the control group at the same time point, the expression levels of TNF-α, IL-6 and IL-1β in group I at T2 and T3 were significantly reduced (p <0.05). The incidence rates of adverse events were similar in the two groups.

CONCLUSIONS

Repeated preoperative intranasal administration of insulin prevented the occurrence of delirium after laparoscopic radical gastrointestinal surgery in elderly patients and reduced TNF-α, IL-1β, and IL-6 levels.

Multi-Order Brain Functional Connectivity Network-Based Machine Learning Method for Recognition of Delayed Neurocognitive Recovery in Older Adults Undergoing Non-cardiac Surgery

Objectives: Delayed neurocognitive recovery (DNR) seriously affects the post-operative recovery of elderly surgical patients, but there is still a lack of effective methods to recognize high-risk patients with DNR. This study proposed a machine learning method based on a multi-order brain functional connectivity (FC) network to recognize DNR.

Method: Seventy-four patients who completed assessments were included in this study, in which 16/74 (21.6%) had DNR following surgery. Based on resting-state functional magnetic resonance imaging (rs-fMRI), we first constructed low-order FC networks of 90 brain regions by calculating the correlation of brain region signal changing in the time dimension. Then, we established high-order FC networks by calculating correlations among each pair of brain regions. Afterward, we built sparse representation-based machine learning model to recognize DNR on the extracted multi-order FC network features. Finally, an independent testing was conducted to validate the established recognition model.

Results: Three hundred ninety features of FC networks were finally extracted to identify DNR. After performing the independent-sample T test between these features and the categories, 15 features showed statistical differences (P < 0.05) and 3 features had significant statistical differences (P < 0.01). By comparing DNR and non-DNR patients’ brain region connection matrices, it is found that there are more connections among brain regions in DNR patients than in non-DNR patients. For the machine learning recognition model based on multi-feature combination, the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity of the classifier reached 95.61, 92.00, 66.67, and 100.00%, respectively.

Conclusion: This study not only reveals the significance of preoperative rs-fMRI in recognizing post-operative DNR in elderly patients but also establishes a promising machine learning method to recognize DNR.

Effect of preoperative hospitalisation period on postoperative cognitive dysfunction in patients undergoing hip surgery under regional anaesthesia

AIM OF THE STUDY

The main objective of this prospective and observational study was to investigate the effect of the preoperative hospitalisation period on early postoperative cognitive dysfunction (POCD) development in patients undergoing total hip replacement surgery under regional anaesthesia.

MATERIALS AND METHODS

Between November 2013 and September 2014, 64 patients were enrolled in the study. Mini Mental Test (MMT) scores were obtained on the initial admission day (MMT1), 24 hours prior to the surgery (MMT2) and 24 hours after the surgery (MMT3). The patients were divided into two groups according to the MMT scores: 'no cognitive dysfunction' (group 1) and 'cognitive dysfunction' (group 2). Differences between the groups were evaluated statistically. The statistical significance level was set as P < .05 in a 95% confidence interval.

RESULTS

The POCD incidence rate was calculated as 43.8% in all patients. The preoperative hospitalisation duration was significantly longer in patients with POCD than in patients without POCD (P < .001). The factors that affected POCD development were found to be advanced age (P < .001), high American Society of Anesthesiologists scores (P = .004), the presence of comorbid disease (P = .025), durations of surgery (P = .018) and decreased postoperative haematocrit levels (P = .014).

CONCLUSION

In this study, we observed that patients with early POCD had relatively longer preoperative hospitalisation periods than those in patients without POCD. We consider that prolonged preoperative hospitalisation may contribute to increased POCD incidence rates in patients with risk factors.

Influence of postoperative analgesia on systemic inflammatory response and postoperative cognitive dysfunction after femoral fractures surgery: a randomized controlled trial

BACKGROUND AND OBJECTIVES

To investigate the possible effect of postoperatively applied analgesics-epidurally applied levobupivacaine or intravenously applied morphine-on systemic inflammatory response and plasma concentration of interleukin (IL)-6 and to determine whether the intensity of inflammatory response is related to postoperative cognitive dysfunction (POCD).

METHODS

This is a randomized, prospective, controlled study in an academic hospital. Patients were 65 years and older scheduled for femoral fracture fixation from July 2016 to September 2017. Inflammatory response was assessed by leukocytes, neutrophils, C reactive protein (CRP) and fibrinogen levels in four blood samples (before anesthesia, 24 hours, 72 hours and 120 hours postoperatively) and IL-6 concentration from three blood samples (before anesthesia, 24 hours and 72 hours postoperatively). Cognitive function was assessed using the Mini-Mental State Examination preoperatively, from the first to the fifth postoperative day and on the day of discharge.

RESULTS

The study population included 70 patients, 35 in each group. The incidence of POCD was significantly lower in the levobupivacaine group (9%) than in the morphine group (31%) (p=0.03). CRP was significantly lower in the levobupivacaine group 72 hours (p=0.03) and 120 hours (p=0.04) after surgery. IL-6 values were significantly lower in the levobupivacaine group 72 hours after surgery (p=0.02). The only predictor of POCD in all patients was the level of IL-6 72 hours after surgery (p=0.03).

CONCLUSIONS

There is a statistically significant association between use of epidural levobupivacaine and a reduction in some inflammatory markers. Postoperative patient-controlled epidural analgesia reduces the incidence of POCD compared with intravenous morphine analgesia in the studied population.

TRIAL REGISTRATION NUMBER

NCT02848599.

Rapamycin improves sevoflurane‑induced cognitive dysfunction in aged rats by mediating autophagy through the TLR4/MyD88/NF‑κB signaling pathway

The present study was aimed to observe the protective effect of rapamycin on cognitive dysfunction induced by sevoflurane in aged rats and its effect on autophagy-related proteins, and to investigate the regulatory mechanism of the Toll-like receptor 4/myeloid differentiation primary response 88/nuclear factor-κB (TLR4/MyD88/NF-κB) signaling pathway. Fifty Sprague-Dawley rats were randomly assigned to a control group, a sevoflurane group, a rapamycin pretreatment group, a TLR4 inhibitor group and a 3MA autophagy inhibitor group. A water maze test was used to evaluate the cognition and memory of rats. Hematoxylin and eosin (H&E) staining was performed to observe pathological changes of brain tissue. A TUNEL assay was used to detect the apoptosis of brain tissue. ELISA was used to assess changes in brain injury markers and inflammatory factors. A western blot assay or quantitative reverse transcription PCR (RT-qPCR) were performed to determine the expression of autophagy-related proteins and the TLR4/MyD88/NF-κB signaling pathway in brain tissue. The results revealed that rapamycin could improve cognitive dysfunction of aged rats induced by sevoflurane. Rapamycin was identified to play a therapeutic role, including mitigating brain tissue damage, inhibiting apoptosis, and activating autophagy in a sevoflurane-treated aged rat model. This function of rapamycin was demonstrated to depend on the TLR4/MyD88/NF-κB signaling pathway.

Malondialdehyde on postoperative day 1 predicts postoperative cognitive dysfunction in elderly patients after hip fracture surgery

Background: Postoperative cognitive dysfunction (POCD) is a great problem for anesthetized subjects and is associated with poor short- and long-term outcomes. We explored promising predictors for POCD in elderly patients after hip fracture surgery.Methods: Elderly subjects (aged ≥65 years) undergoing surgery for hip fracture were consecutively recruited. Neuropsychological assessments were performed 1 day preoperatively (baseline) and 7 days postoperatively, and POCD was defined using the 'Z scores' method. Clinical data and laboratory tests were compared between patients with and without POCD development. Binary univariate and multivariate logistic regression analyses were conducted for risk factor assessment. Receiver operating characteristic (ROC) curve analysis was performed to investigate the predictive value of malondialdehyde (MDA) on postoperative day 1 (POD1) for POCD.Results: A total of 198 patients were finally enrolled in the analysis and 51 patients exhibited POCD within 7 postoperative days, with an incidence rate of 25.8%. MDA expression on POD1 (OR: 1.12, 95%CI: 1.03-1.23, P=0.017) was the only independent risk factor for POCD according to the final multivariate logistic regression analysis. ROC curve analysis indicated that MDA on POD1 was a predictor for POCD, with an area under the curve (AUC) of 0.683 and 95%CI of 0.590-0.775 (P<0.001).Conclusions: In conclusion, we demonstrated that MDA on POD1 was an independent risk factor for POCD in elderly subjects undergoing hip fracture surgery.

General versus spinal anesthesia for the elderly hip fractured patient

PURPOSE OF REVIEW

There is an urge to improve care for patients with hip fracture. The present review will compare the efficacy of spinal versus general anesthesia for patients requiring hip fracture surgery.

RECENT FINDINGS

The present review gives an overview with particular emphasis on literature published during the past 24 months.

SUMMARY

So far, no clear evidence form randomized trials exists to identify the best anesthesia technique for hip fracture surgery. However, several large-scale pragmatic trials are ongoing and will provide future guidance.

Inhibition of α5 GABAA receptors has preventive but not therapeutic effects on isoflurane-induced memory impairment in aged rats

The α5 subunit-containing gamma-amino butyric acid type A receptors (α5 GABAARs) are a distinct subpopulation that are specifically distributed in the mammalian hippocampus and also mediate tonic inhibitory currents in hippocampal neurons. These tonic currents can be enhanced by low-dose isoflurane, which is associated with learning and memory impairment. Inverse agonists of α5 GABAARs, such as L-655,708, are able to reverse the short-term memory deficit caused by low-dose isoflurane in young animals. However, whether these negative allosteric modulators have the same effects on aged rats remains unclear. In the present study, we mainly investigated the effects of L-655,708 on low-dose (1.3%) isoflurane-induced learning and memory impairment in elderly rats. Young (3-month-old) and aged (24-month-old) Wistar rats were randomly assigned to receive L-655,708 0.5 hour before or 23.5 hours after 1.3% isoflurane anesthesia. The Morris Water Maze tests demonstrated that L-655,708 injected before or after anesthesia could reverse the memory deficit in young rats. But in aged rats, application of L-655,708 only before anesthesia showed similar effects. Reverse transcription-polymerase chain reaction showed that low-dose isoflurane decreased the mRNA expression of α5 GABAARs in aging hippocampal neurons but increased that in young animals. These findings indicate that L-655,708 prevented but could not reverse 1.3% isoflurane-induced spatial learning and memory impairment in aged Wistar rats. All experimental procedures and protocols were approved by the Experimental Animal Ethics Committee of Academy of Military Medical Science of China (approval No. NBCDSER-IACUC-2015128) in December 2015.

A comprehensive analysis of patient satisfaction with anesthesia

Background:

Patient satisfaction with anesthesia after surgical treatment is a complex concept that includes not only the level of satisfaction with the anesthesia itself but also the presence of fears, worries, depression, evaluation of the anesthesiologists' work, as well as cognitive dysfunction as a possible negative consequence of anesthesia.

Objective:

Conducting a comprehensive analysis of patients' satisfaction with anesthesia.

Methods:

Questionnaire of patients' satisfaction with anesthesia (Sinbukhova E.V., Lubnin A.Yu.), State-Trait Anxiety Inventory in the adaptation by Y.L. Hanin, Assessment of Depression, The Montreal Cognitive Assessment (MoCA), and Frontal Assessment Battery. Population consisted of 202 patients.

Results:

Satisfaction with anesthesia: assessment “good and higher” with primary anesthesia – 59.7% of patients with repeated – 70% of patients. The most common factors that reduce the assessment of patients' satisfaction with anesthesia are: strong excitement before surgery about operation and anesthesia, no postoperative visit of the anesthesiologist, no visit of the anesthesiologist before the operation, not enough attention of anesthesiologist in the surgery room before anesthesia, nausea, vomiting, pain, dizziness, general discomfort, and thirst. MoCA cognitive assessment before and after anesthesia: P < 2.2 e–16 (significant decrease). Depression: major depression in 52% of patients, subclinical depression in 22.8%.

Conclusion:

Regular survey of patients' satisfaction should help to improve the quality of medical care. The strong excitement of the patient about the upcoming anesthesia and surgery, and the presence of a high level of anxiety and depression can be factors of reducing the patients' satisfaction with anesthesia. It requires psychological support of patients at the stage of surgical treatment.

Dexmedetomidine protects rats from postoperative cognitive dysfunction via regulating the GABAB R-mediated cAMP-PKA-CREB signaling pathway

This work attempts to discuss whether dexmedetomidine (Dex) can protect rats from postoperative cognitive dysfunction (POCD) through regulating the γ-aminobutyric acid-_B receptor (GABA_B R)-mediated cyclic adenosine monophosphate (cAMP) - protein kinase A (PKA) - cAMP-response element binding (cAMP-PKA-CREB) signaling pathway. Sprague-Dawley rats were divided into a non-surgical group (Control), a surgical group (Model), a surgical group treated with Dex (Model + Dex), a surgical group treated with GABA_B R antagonist (Model + CGP 35348) and a surgical group treated with Dex and GABA_B R agonist (Model + Dex + Baclofen). Cognitive and memory functions were evaluated by Y-maze test and open-field test. The neuronal morphology of the hippocampus was observed by hematoxylin and eosin staining and neuronal apoptosis was by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling method. Inflammatory factors and cAMP levels were detected by enzyme-linked immunosorbent assay while expressions of GABA_B R and PKA-CREB pathway-related molecules by Western blot. Compared with control rats, the model rats exhibited reduced alternation rates with a prolonged time spent in the central zone; meanwhile, levels of tumor necrosis factor-α and interleukin-1β and the apoptotic index, as well as GABA_B R1 and GABA_B R2 expressions were increased in the model rats, but the cAMP-PKA-CREB pathway was inhibited (all P < 0.05). When treated with either Dex or CGP 35348, the surgical rats displayed an opposite tendency concerning the above factors as compared to the model rats (all P < 0.05). Furthermore, Baclofen, the agonist of GABA_B R, could reverse the protective effect of Dex against POCD in rats. Dex protects rats from POCD possibly via suppressing GABA_B R to up-regulate the cAMP-PKA-CREB signaling pathway, thereby alleviating the hippocampal inflammation caused by surgical trauma.

Effects of ADAM2 silencing on isoflurane-induced cognitive dysfunction via the P13K/Akt signaling pathway in immature rats

Volatile anesthetics, including isoflurane, have been reported to have negative effects on cognitive dysfunction characterized by cognitive deficits following anesthesia. The aim of the current study was to investigate the effects involved with disintegrin and metallopeptidase domain 2 (ADAM2) silencing on isoflurane-induced cognitive dysfunction via the P13 K/Akt signaling pathway in immature rats. One week old healthy Sprague-Dawley (SD) rats were recruited and administered isoflurane anesthesia. The rats were then subjected to shADAM2 or wortmannin (PI3K/Akt signaling pathway inhibitor) to identify the effects of ADAM2 and the PI3K/Akt signaling pathway on the cognitive function of rats. Morris water maze and passive-avoidance tests were performed to examine the cognitive function of the rats. TUNEL staining was conducted to detect neuronal apoptosis in the hippocampal CA1 region. The obtained experimental results demonstrated that isoflurane anesthesia led to increased escape latency, reaction time, number of errors and TUNEL-positive neurons, along with a decreased latency time. In response to treatment with shADAM2, escape latency, reaction time, number of errors and TUNEL-positive cells were all noted to have decreased, in addition to elevated latency time, while contrasting trends were observed in regard to treatment with wortmannin. Taken together, the key findings of the present study revealed that shADAM2 activated the PI3K/Akt signaling pathway, resulting in elevated expressions of PI3K and Akt. Our study ultimately identified that ADAM2 silencing alleviates isoflurane-induced cognitive dysfunction by activating the P13 K/Akt signaling pathway in immature rats.

Improve hip fracture outcome in the elderly patient (iHOPE): a study protocol for a pragmatic, multicentre randomised controlled trial to test the efficacy of spinal versus general anaesthesia

INTRODUCTION

Hip fracture surgery is associated with high in-hospital and 30-day mortality rates and serious adverse patient outcomes. Evidence from randomised controlled trials regarding effectiveness of spinal versus general anaesthesia on patient-centred outcomes after hip fracture surgery is sparse.

METHODS AND ANALYSIS

The iHOPE study is a pragmatic national, multicentre, randomised controlled, open-label clinical trial with a two-arm parallel group design. In total, 1032 patients with hip fracture (>65 years) will be randomised in an intended 1:1 allocation ratio to receive spinal anaesthesia (n=516) or general anaesthesia (n=516). Outcome assessment will occur in a blinded manner after hospital discharge and inhospital. The primary endpoint will be assessed by telephone interview and comprises the time to the first occurring event of the binary composite outcome of all-cause mortality or new-onset serious cardiac and pulmonary complications within 30 postoperative days. In-hospital secondary endpoints, assessed via in-person interviews and medical record review, include mortality, perioperative adverse events, delirium, satisfaction, walking independently, length of hospital stay and discharge destination. Telephone interviews will be performed for long-term endpoints (all-cause mortality, independence in walking, chronic pain, ability to return home cognitive function and overall health and disability) at postoperative day 30±3, 180±45 and 365±60. ETHICS AND DISSEMINATION: iHOPE has been approved by the leading Ethics Committee of the Medical Faculty of the RWTH Aachen University on 14 March 2018 (EK 022/18). Approval from all other involved local Ethical Committees was subsequently requested and obtained. Study started in April 2018 with a total recruitment period of 24 months. iHOPE will be disseminated via presentations at national and international scientific meetings or conferences and publication in peer-reviewed international scientific journals.

TRIAL REGISTRATION NUMBER

DRKS00013644; Pre-results.

Postoperative Cognitive Dysfunction Induced by Different Surgical Methods and Its Risk Factors

The aim of the present study was to compare the effect of different surgical methods on postoperative cognitive function in patients undergoing abdominal surgery, determine the risk factors of postoperative cognitive dysfunction (POCD) by logistic regression, and investigate these risk factors through different surgical methods. A total of 70 patients undergoing selective abdominal surgery were selected into this study. The age of these patients ranged within 32 to 85 years. The cognitive function of these patients was assessed by the mini-mental state examination at one day before the operation, and at the first and seventh day after the operation. The temperature of the tympanic membrane, PETCO2 values, visual analogue scale scores, educational level, and operation time were recorded. Logistic regression analysis was used to analyze related factors of POCD. The incidence rate of perioperative hypothermia in groups O and L were 31.2 and 10.5 per cent, respectively; and the difference was statistically significant (P < 0.05). The difference in visual analogue scale scores at the first and seventh day after the operation between these two groups were statistically significant (P < 0.01). The incidence of POCD in group O was significantly higher than that in group L at the first and seventh day after the operation (P < 0.05). According to logistic regression results, it was found that age, perioperative hypothermia, and postoperative pain were risk factors of POCD. The difference in POCD for the patients undergoing abdominal surgery through different surgical methods was statistically significant, and this was closely correlated to perioperative hypothermia and postoperative pain.

Does Dexmedetomidine Ameliorate Postoperative Cognitive Dysfunction? A Brief Review of the Recent Literature

PURPOSE OF REVIEW

Postoperative cognitive dysfunction (POCD) occurs in 20-50% of postsurgical patients with a higher prevalence in elderly patients and patients with vascular disease and heart failure. In addition, POCD has been associated with many negative outcomes, such as increased hospital length of stay, increased rates of institutionalization, and higher patient mortality. This brief review discusses select evidence suggesting an association between neuroinflammation and POCD and whether the use of dexmedetomidine, a short-acting alpha 2 agonist, may ameliorate the incidence of POCD. We review the recent evidence for neuroinflammation in POCD, dexmedetomidine's properties in reducing inflammatory-mediated brain injury, and clinical studies of dexmedetomidine and POCD.

RECENT FINDINGS

There is evidence to support the anti-inflammatory and immunomodulatory effects of dexmedetomidine in animal models. Several clinical investigations have demonstrated favorable outcomes using dexmedetomidine over placebo for the reduction of postoperative delirium. Few studies have used high-quality endpoints for the assessment of POCD and no demonstrable evidence supports the use of dexmedetomidine for the prevention of POCD. While evidence exists for the neural anti-inflammatory properties of dexmedetomidine, human trials have yielded incomplete results concerning its use for the management of POCD. Dexmedetomidine may reduce acute postoperative delirium, but further studies are needed prior to recommending the use of dexmedetomidine for the direct reduction of POCD.

Administrations of Preoperative Shenmai Injection and Postoperative Shenfu Injection, Two Ginseng Containing TCM Formulas, Improve Cognitive Dysfunction in Aged Rats

Postoperative cognitive dysfunction (POCD) is one of the major complications in patients who have undergone surgeries. Reduction of surgery-induced inflammation and perioperative stress responses may prevent the development of POCD. As recent experimental data have suggested, Shenmai and Shenfu injections, two ginseng containing formulations, may improve cognition. We designed this study using aged rats as an experimental model to determine the effect of combined perioperative Shenmai injection and Shenfu injection in preventing the development of POCD and exploring the underlying mechanism of this intervention. Aged rats were randomized into one of the two groups. Rats in the experiment group received preoperative Shenmai injection and postoperative Shenfu injection while those of the control group did not receive this treatment. Study results indicate that the memory and cognitive ability of rats in the experiment group were significantly better than those of the control group at postoperative day 1 as well as at day 3. Plasma levels of neuron-specific enolase (NSE), S-100 [Formula: see text] protein, interleukin-6 (IL-6), tumor necrosis factor-[Formula: see text] (TNF-[Formula: see text]), cortisol (COR), aldosterone (ALD), and adenocorticotropic hormone (ACTH) were significantly lower in the experiment group than in those of the control group (day 1 postoperatively). The plasma level of NSE on postoperative day 3 remained lower in the experimental group than in those of the control group. Our experimental results indicate that preoperative Shenmai and postoperative Shenfu injections facilitate conscious recovery and prevent postoperative cognitive decline. This anti-POCD effect may be a result of minimizing surgery-induced inflammation and reduction of perioperative stress responses by these injections.

Baden Prevention and Reduction of Incidence of Postoperative Delirium Trial (PRIDe): a phase IV multicenter, randomized, placebo-controlled, double-blind clinical trial of ketamine versus haloperidol for prevention of postoperative delirium

Background

Delirium is a neurobehavioural syndrome that frequently develops in the postoperative setting. The incidence of elderly patients who develop delirium during hospital stay ranges from 10-80%. Delirium was first described more than half a century ago in the cardiac surgery population, where it was already discovered as a state that might be accompanied by serious complications such as prolonged ICU and hospital stay, reduced quality of life and increased mortality. Furthermore, the duration of delirium is associated with worse long-term cognitive function in the general ICU population. This long-term experience with delirium suggests a high socioeconomic burden and has been a focus of many studies. Due to the multifactorial origin of delirium, we have several but no incontestable options for prevention and symptomatic treatment. Overall, delirium represents a high burden not only for patient and family members, but also for the medical care team that aims to prevent postoperative delirium to avoid serious consequences associated with it.

The purpose of this study is to determine whether postoperative delirium can be prevented by the combination of established preventive agents. In addition, measured levels of pre- and postoperative cortisol, neuron specific enolase (NSE) and S-100β will be used to investigate dynamics of these parameters in delirious and non-delirious patients after surgery.

Methods/design

The Baden PRIDe Trial is an investigator-initiated, phase IV, two-centre, randomised, placebo-controlled, double-blind clinical trial for the prevention of delirium with haloperidol, ketamine, and the combination of both vs. placebo in 200 patients scheduled for surgery. We would like to investigate superiority of one of the three treatment arms (i.e., haloperidol, ketamine, combined treatment) to placebo.

Discussion

There is limited but promising evidence that haloperidol and ketamine can be used to prevent delirium. Clinical care for patients might improve as the results of this study may lead to better algorithms for the prevention of delirium.

Trial registration

ClinicalTrials.gov, NCT02433041. Registered on 7 April 2015.

Swiss National Clinical Trial Portal, SNCTP000001628. Registered on 9 December 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2498-6) contains supplementary material, which is available to authorized users.

Task-related changes in degree centrality and local coherence of the posterior cingulate cortex after major cardiac surgery in older adults

OBJECTIVES

Older adults often display postoperative cognitive decline (POCD) after surgery, yet it is unclear to what extent functional connectivity (FC) alterations may underlie these deficits. We examined for postoperative voxel-wise FC changes in response to increased working memory load demands in cardiac surgery patients and nonsurgical controls.

EXPERIMENTAL DESIGN

Older cardiac surgery patients (n = 25) completed a verbal N-back working memory task during MRI scanning and cognitive testing before and 6 weeks after surgery; nonsurgical controls with cardiac disease (n = 26) underwent these assessments at identical time intervals. We measured postoperative changes in degree centrality, the number of edges attached to a brain node, and local coherence, the temporal homogeneity of regional functional correlations, using voxel-wise graph theory-based FC metrics. Group × time differences were evaluated in these FC metrics associated with increased N-back working memory load (2-back > 1-back), using a two-stage partitioned variance, mixed ANCOVA.

PRINCIPAL OBSERVATIONS

Cardiac surgery patients demonstrated postoperative working memory load-related degree centrality increases in the left dorsal posterior cingulate cortex (dPCC; p < .001, cluster p-FWE < .05). The dPCC also showed a postoperative increase in working memory load-associated local coherence (p < .001, cluster p-FWE < .05). dPCC degree centrality and local coherence increases were inversely associated with global cognitive change in surgery patients (p < .01), but not in controls.

CONCLUSIONS

Cardiac surgery patients showed postoperative increases in working memory load-associated degree centrality and local coherence of the dPCC that were inversely associated with postoperative global cognitive outcomes and independent of perioperative cerebrovascular damage.

Efficacy and Safety of 3 Different Anesthesia Techniques Used in Total Hip Arthroplasty

Background

This study compared the efficacy and safety of 3 different anesthesia techniques used in total hip arthroplasty (THA).

Material/Methods

We allocated 198 patients preparing to undertake THA into 3 groups: general anesthesia group (GA group, n=66), caudal epidural anesthesia group (CEA group, n=66), and spinal-epidural anesthesia group (SEA group, n=66). We compared postoperative adverse effects occurring in patients of the 3 anesthesia groups. The Visual Analog Scale (VAS) score, Minimum Mental State Examination (MMSE) score, and β-amyloid (Aβ) expression were calculated to determine the effects of different anesthesia on the postoperative pain and cognitive dysfunction of patients.

Results

The CEA and SEA groups had lower rates of perioperative adverse effects than in the GA group. Patients in the GA group required significantly higher administration of analgesics after the surgery than those in CEA and SEA groups. Higher Aβ expression levels and VAS scores, as well as lower MMSE scores, were also seen in the GA group compared with the other 2 groups.

Conclusions

CEA and SEA were more effective than GA in THA, and CEA seemed to be a better anesthesia technique than SEA.

Autophagy Is Involved in the Sevoflurane Anesthesia-Induced Cognitive Dysfunction of Aged Rats

Autophagy is associated with regulation of both the survival and death of neurons, and has been linked to many neurodegenerative diseases. Postoperative cognitive dysfunction is commonly observed in elderly patients following anesthesia, but the pathophysiological mechanisms are largely unexplored. Similar effects have been found in aged rats under sevoflurane anesthesia; however, the role of autophagy in sevoflurane anesthesia-induced hippocampal neuron apoptosis of older rats remains elusive. The present study was designed to investigate the effects of autophagy on the sevoflurane-induced cognitive dysfunction in aged rats, and to identify the role of autophagy in sevoflurane-induced neuron apoptosis. We used 20-month-old rats under sevoflurane anesthesia to study memory performance, neuron apoptosis, and autophagy. The results demonstrated that sevoflurane anesthesia significantly impaired memory performance and induced hippocampal neuron apoptosis. Interestingly, treatment of rapamycin, an autophagy inducer, improved the cognitive deficit observed in the aged rats under sevoflurane anesthesia by improving autophagic flux. Rapamycin treatment led to the rapid accumulation of autophagic bodies and autophagy lysosomes, decreased p62 protein levels, and increased the ratio of microtubule-associated protein light chain 3 II (LC3-II) to LC3-I in hippocampal neurons through the mTOR signaling pathway. However, administration of an autophagy inhibitor (chloroquine) attenuated the autophagic flux and increased the severity of sevoflurane anesthesia-induced neuronal apoptosis and memory impairment. These findings suggest that impaired autophagy in the hippocampal neurons of aged rats after sevoflurane anesthesia may contribute to cognitive impairment. Therefore, our findings represent a potential novel target for pro-autophagy treatments in patients with sevoflurane anesthesia-induced neurodegeneration.

Impact of Controlled Induced Hypotension on Cognitive Functions of Patients Undergoing Functional Endoscopic Sinus Surgery

Background

Controlled induced hypotension guarantees less blood loss and better visibility of the surgical site. The impact of hypotension on post-operative cognitive functions is still being discussed. The objective of this study was to evaluate the effects of controlled induced hypotension on the cognitive functions of patients undergoing functional endoscopic sinus surgery (FESS).

Material/Methods

We allocated 47 patients with a good grade of preoperative cognitive functions evaluated with the Mini-Mental State Examination to 3 groups (1 – mild hypotension, 2 – intermediate hypotension, 3 – severe hypotension) according to the degree of mean intraoperative arterial pressure compared with preoperative blood pressure. Cognitive functions were evaluated preoperatively, 6 h, and 30 h postoperatively with standardized tests: the Stroop Test, Trail Making Test (TMT), and Verbal Fluency Test (VFT). A decrease in the test results and increase in the number of mistakes made were considered an impairment of cognitive functions.

Results

A total of 47 patients (group 1 – mild hypotension – 15, group 2 – intermediate hypotension – 19, group 3 – severe hypotension – 13) were included in the study. A significant decrease was observed in all the 3 groups after Stroop A test 6h postoperatively but it improved 30h postoperatively, without differences between the groups. Neither a significant decrease in the test results nor an increase in the number of mistakes was noted for Stroop B tests, TMT A&B tests and VFT.

Conclusions

The degree of controlled intraoperative hypotension during FESS did not influence the results of psychometric tests.

Biomarkers of Brain Damage and Postoperative Cognitive Disorders in Orthopedic Patients: An Update

The incidence of postoperative cognitive dysfunction (POCD) in orthopedic patients varies from 16% to 45%, although it can be as high as 72%. As a consequence, the hospitalization time of patients who developed POCD was longer, the outcome and quality of life were worsened, and prolonged medical and social assistance were necessary. In this review the short description of such biomarkers of brain damage as the S100B protein, NSE, GFAP, Tau protein, metalloproteinases, ubiquitin C terminal hydrolase, microtubule-associated protein, myelin basic protein, α-II spectrin breakdown products, and microRNA was made. The role of thromboembolic material in the development of cognitive decline was also discussed. Special attention was paid to optimization of surgical and anesthetic procedures in the prevention of postoperative cognitive decline.

Intracisternal administration of an interleukin-6 receptor antagonist attenuates surgery-induced cognitive impairment by inhibition of neuroinflammatory responses in aged rats

Postoperative cognitive dysfunction (POCD) is common in elderly patients, and may persist or even evolve into Alzheimer's disease. It has been hypothesized that POCD is mediated by surgery-induced inflammatory processes. As a pro-inflammatory cytokine, the detailed role of interleukin (IL)-6 in POCD remains largely unknown. In this study, laparotomy was used to mimic human abdominal surgery in aged Sprague-Dawley rats. It was found that memory and learning were impaired following surgery, accompanied by the significant upregulation of the pro-inflammatory cytokines tumor necrosis factor α (TNF-α), IL-1β, IL-4, and IL-6. Moreover, the intracisternal administration of the IL-6 receptor (IL-6R) antagonist (tocilizumab, also know as MRA) at the time of surgery notably attenuated the surgery-induced cognitive deficit, and significantly inhibited the upregulated expression of pro-inflammatory cytokines. Further investigation indicated that the intracisternal administration of MRA inhibited the activation of the NF-κB signaling pathway in aged rats following surgery. In summary, the findings of this study suggest that IL-6 plays a crucial role in POCD, and that IL-6R antagonists may serve as novel agents for the prevention or treatment of POCD.

Predictors of Postoperative Cognitive Decline in Very Old Patients With Hip Fracture: A Retrospective Analysis

BACKGROUND

To investigate incidence and predictors of the various postoperative cognitive declines in old patients with hip fracture.

METHODS

This retrospective chart study evaluated 411 patients (age ≥80 years, follow-up 5 years). After exclusion of 82 patients (preexisting dementia or delirium), 70 patients showing either diagnosed postoperative delirium (POD; group 1; N = 18, 5.5%) or an unspecified cognitive dysfunction and behavior (group 2; N = 52, 15.8%) were analyzed and compared with those without any acute postoperative cerebral impairment (control group; N = 259, 78.7%). Medical history, anesthesiological, orthopedic, and rehabilitation data were assessed using the medical database of the hospital information system. Relative ratio was calculated with Fisher exact test: P value Bonferroni corrected ≤.003.

RESULTS

Acute cognitive complications were observed in 70 (21.3%) patients. Our data in group 1 showed that patients with a medical history of stroke (relative risk [RR] = 16.2, P = .0001) or nicotine abuse (RR = 14.4, P = .001) and perioperative surgical bleeding (RR = 6.54, P = .002) are more likely to develop POD. Unspecified cognitive dysfunction and behavior (group 2) was significantly associated with a medical history of stroke (RR = 12.5, P = .0001) and postoperatively with depression (RR = 3.32, P = .001). In the follow-up, significantly more patients in group 1 (55.6%, RR = 21.8, P = .0001) and group 2 (13.5%, RR = 3.88, P = .001) developed dementia as compared to controls (1.9%). Mortality did not differ significantly between the groups (group 1: RR = 1.75, P = .5 and group 2: RR = 0.66, P = 1.0).

CONCLUSION

These data show that various predictors can identify a greater likelihood of developing postoperative cognitive decline in very old patients with hip fracture. Not identifying or labeling of POD limits the opportunity for evaluation, treatment, and planning. Thus, routine cognitive assessments need to be performed in the scope of multidisciplinary orthogeriatric comanagement.

Postoperative cognitive dysfunction: current developments in mechanism and prevention

Postoperative cognitive dysfunction (POCD) is a subtle disorder of thought processes, which may influence isolated domains of cognition and has a significant impact on patient health. The reported incidence of POCD varies enormously due to lack of formal criteria for the assessment and diagnosis of POCD. The significant risk factors of developing POCD mainly include larger and more invasive operations, duration of anesthesia, advanced age, history of alcohol abuse, use of anticholinergic medications, and other factors. The release of cytokines due to the systemic stress response caused by anesthesia and surgical procedures might induce the changes of brain function and be involved in the development of postoperative cognitive dysfunction. The strategies for management of POCD should be a multimodal approach involving close cooperation between the anesthesiologist, surgeon, geriatricians, and family members to promote early rehabilitation and avoid loss of independence in these patients.

Critical care strategies to improve neurocognitive outcome in thoracic surgery

PURPOSE OF REVIEW

This review focuses on neurocognitive outcome with respect to potential pathophysiological inflammatory mechanisms of thoracic surgery and one-lung ventilation, risk factors of postoperative delirium and postoperative cognitive dysfunction (POCD) as well as anti-inflammatory strategies.

RECENT FINDINGS

Neurocognitive dysfunction is associated with increased mortality and disability. The incidence of postoperative delirium and POCD is often underestimated in the perioperative care setting. Both are threatening complications after major surgery and independently associated with an increased morbidity and mortality. Nevertheless, in thoracic surgery, the clinical relevance of neurocognitive dysfunction is still underestimated. Currently, there has been a growing interest in inflammation as a cause of the pathogenesis of postoperative delirium and POCD. Furthermore, thoracic surgery often requires one-lung ventilation, which is accompanied with important physiological disturbances, and leads to a pulmonary arteriovenous shunt with the decrease of arterial oxygen content and an exaggerated activation of inflammatory processes. As inflammation is involved in brain dysfunction, anti-inflammatory strategies in the perioperative setting seem to be potential neuroprotective targets concerning specially high-risk patients undergoing thoracic surgery under one-lung ventilation.

SUMMARY

There is evidence that important key strategies improve neurocognitive outcome after thoracic surgery. This includes adequate risk stratification, the anesthetic management and postoperative critical care strategies.

Protective effect of senegenin on splenectomy-induced postoperative cognitive dysfunction in elderly rats

Postoperative cognitive dysfunction (POCD) is common in elderly patients. Senegenin, an active component of extracts from Polygala tenuifolia root, a traditional Chinese medicine, has neuroprotective and neuroregenerative effects. However, the mechanism underlying the effects of senegenin against postoperative cognitive impairment in elderly individuals has yet to be elucidated. The aim of this study was to investigate the protective effects of senegenin on the cognitive functions of elderly rats with splenectomy-induced POCD. Results from a Morris water maze test suggested that splenectomy induced a transient cognitive deficiency in the elderly rats; however, when the rats were treated with senegenin, the cognitive impairment was notably attenuated. Further experiments showed that senegenin significantly inhibited the mRNA and protein expression of several key pro-inflammatory cytokines, specifically, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-8, in the hippocampal tissues of elderly rats following splenectomy. In order to investigate the molecular mechanism involved, the expression and activity of the Toll-like receptor 4 (TLR4) signaling pathway was assessed. On day 1 postoperatively, it was observed that senegenin markedly suppressed the mRNA and protein expression of TLR4, myeloid differentiation factor 88 (MyD88) and TIR domain-containing adaptor-inducing interferon-β (TRIF). Furthermore, the phosphorylation levels of nuclear factor-κB (NF-κB) p65 and inhibitor of NF-κB (IκBα) were also decreased following senegenin treatment on the first day subsequent to surgery. These results suggest that senegenin suppressed splenectomy-induced transient cognitive impairment in elderly rats, possibly by downregulating two signaling pathways involved in inflammation, TLR4/MyD88/NF-κB and TLR4/TRIF/NF-κB, to further inhibit the expression of key pro-inflammatory cytokines, specifically, TNF-α, IL-1β, IL-6 and IL-8, and ultimately the neuroinflammation in the hippocampal tissues. In conclusion, the present study revealed that senegenin exhibited neuroprotective effects against splenectomy-induced transient cognitive impairment in elderly rats, which indicated that senegenin may be a promising agent for the treatment of POCD.

Melatonin attenuates isoflurane-induced acute memory impairments in aged rats

Melatonin is an endogenous hormone with neuroprotective effects. Melatonin levels in elderly patients are reduced after surgeries that require anaesthesia. Whether reduced melatonin levels are important for postoperative cognitive dysfunction (POCD) remains unclear. Here, we investigated the effects of melatonin on cognitive dysfunctions induced by isoflurane and mechanisms underlying these effects. Seventy-two 20-month-old Sprague-Dawley rats were randomly divided into six groups (n = 12). These groups included M1 and M10 groups that received intraperitoneal melatonin at 1 mg/kg or 10 mg/kg, respectively, and an ISO group that received 4 hr of inhaled 2% isoflurane. They also included M1+ISO and M10+ISO groups that received 1 mg/kg or 10 mg/kg of melatonin plus 4 hr of inhaled 2% isoflurane, respectively, and a control group that received an equal volume of saline. Injections were administered daily for 14 consecutive days. Memory was assessed in the Morris water maze. Plasma and hippocampi were harvested to determine melatonin concentrations and MT1/MT2 receptor expression. Rats treated only with isoflurane showed significantly longer latencies in Morris water maze test trials compared with the control group, with shorter time in the probe trial (p < 0.05). Although plasma melatonin levels and MT2 expression in the hippocampus were significantly decreased, MT1 expression was higher in the isoflurane group than in the control group (p < 0.001). However, these parameters did not significantly vary in animals administered melatonin compared with controls. Isoflurane may induce cognitive dysfunction by influencing melatonin and MT1/MT2 levels. Melatonin can improve cognitive dysfunction by normalizing plasma melatonin and its receptor levels.

The role of the TLR4 signaling pathway in cognitive deficits following surgery in aged rats

Postoperative cognitive dysfunction (POCD), common in elderly patients, refers to a decline in cognitive function following surgery, which may persist or even evolve into Alzheimer's disease (AD). Despite great efforts, the mechanism of POCD remains unclear. In the present study, we tested the hypothesis that Toll-like receptor 4 (TLR4) on microglia contributes to POCD. Shortly after surgery, aged rats demonstrated significant deficits in memory and learning, accompanied by the activation of microglia, marked upregulation of TLR4 on microglia in the hippocampus, as well as an increased expression of two downstream factors [myeloid differentiation factor 88 (MyD88) and TIR-domain-containing adapter-inducing interferon-β (TRIF)] and pro-inflammatory cytokines [including tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β)]. With an increase in time following surgery, the expression of TLR4 and the aforementioned factors and pro-inflammatory cytokines gradually returned to normal, as did the cognitive function of the aged rats. In conclusion, our study suggests that the activation of TLR4 signaling on microglia may act as an underlying mechanism of POCD.

[Anesthesia for geriatric patients. Part 1: age, organ function and typical diseases]

Due to demographic changes in the population of industrial nations the number of elderly patients undergoing elective or emergency procedures will rise significantly in the coming years. Anesthesia for geriatric patients is challenging for the anesthesiologist in many ways: with increasing age numerous physiological changes occur which all lead to a subsequent reduction of physical performance and compensatory capacity of the organism, in many cases additionally aggravated by chronic illness. Subsequently, these age-dependent changes (with or without chronic illness) increase the risk for admission to intensive care units, perioperative death, treatment costs and a prolonged length of hospital stay. Therefore, subtle preoperative assessment and tailored anesthetic management are essential in elderly patients. Part 1 of this continuous education article covers the influence of age on organ functions and describes typical comorbidities which are of high relevance for the perioperative care of geriatric patients. The special features of anesthetic agents and anesthesia management in the elderly will be presented in part 2.