Anaesthesia in the older patient

Transcutaneous electrical acupoint stimulation for the prevention of perioperative neurocognitive disorders in geriatric patients: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

To evaluate whether transcutaneous electrical acupoint stimulation (TEAS) decreases rates of perioperative neurocognitive disorders (PND) when used as an adjuvant method during perioperative period in geriatric patients since the new definition was released in 2018.

METHODS

Six databases [Chinese National Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals, WanFang Database, PubMed, EMBASE, and Cochrane Library] were systematically searched. Data analysis was performed using RevMan 5.4.1 software (Copenhagen: The Nordic Cochrane Centre, the Cochrane Collaboration, 2020). Risk ratios (RR) with 95% confidence interval were calculated using a random effects model. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

13 randomized clinical trials (999 patients) in total were included. TEAS had positive effects on preventing the incidence of PND (RR: 0.43; 0.31, 0.61; P < .001; low certainty) [postoperative delirium within 7 days (RR: 0.39; 0.26, 0.59; P < .001), delayed neurocognitive recovery within 3 months (RR: 0.51; 0.33, 0.78; P = .002)]. TEAS could also improve the scores of the confusion assessment method (CAM) (Mean difference: -1.30; -2.14, -0.46; P = .003; low certainty). Limited evidence suggested that TEAS could reduce the serum levels of biochemical indicator (S100β) (SMD = -1.08, -1.67, -0.49, P < .001; I2  = 83%; very low certainty) as well as anesthetic requirements (remifentanil) (SMD: -1.58; -2.54, -0.63; P = .001; I2  = 87%; very low certainty). Subgroup analysis indicated that different protocols of TEAS had significant pooled benefits (TEAS used only in surgery and in combination with postoperative intervention) (RR: 0.45; 0.31, 0.63; P < .001). Acupoint combination (LI4 and PC6) in the TEAS group had more significantly advantages (RR: 0.34; 0.17, 0.67; P = .002). TEAS group had a lower incidence of PND in different surgery type (orthopedic surgery and abdominal surgery) (RR: 0.43; 0.30, 0.60; P < .001), as well as with different anesthetic modality (intravenous anesthesia and intravenous and inhalational combined anesthesia) (RR: 0.38; 0.23, 0.61; P < .001).

CONCLUSION

In terms of clinical effectiveness, TEAS appeared to be beneficial for prophylaxis of PND during a relatively recent period, noting the limitations of the current evidence.

NLRP3 inflammasomes are involved in the progression of postoperative cognitive dysfunction: from mechanism to treatment

Postoperative cognitive dysfunction (POCD) involves patient memory and learning decline after surgery. POCD not only presents challenges for postoperative nursing and recovery but may also cause permanent brain damage for patients, including children and the aged, with vulnerable central nervous systems. Its occurrence is mainly influenced by surgical trauma, anesthetics, and the health condition of the patient. There is a lack of imaging and experimental diagnosis; therefore, patients can only be diagnosed by clinical observation, which may underestimate the morbidity, resulting in decreased treatment efficacy. Except for symptomatic support therapy, there is a relative lack of effective drugs specific for the treatment of POCD, because the precise mechanism of POCD remains to be determined. One current hypothesis is that postoperative inflammation promotes the progression of POCD. Accumulating research has indicated that overactivation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes contribute to the POCD progression, suggesting that targeting NLRP3 inflammasomes may be an effective therapy to treat POCD. In this review, we summarize recent studies and systematically describe the pathogenesis, treatment progression, and potential treatment options of targeting NLRP3 inflammasomes in POCD patients.

Effect of pre-emptive analgesia by continuous femoral nerve block on early postoperative cognitive function following total knee arthroplasty in elderly patients

To the best of our knowledge, the effect of pre-emptively blocking pain transmission on acute postoperative cognitive dysfunction (POCD) has not yet been assessed. Therefore, the present study aimed to investigate the effect of pre-emptive analgesia via a continuous femoral nerve block (CFNB) on postoperative pain and early cognitive function following total knee arthroplasty (TKA) surgery in elderly patients. CFNB was performed prior to TKA surgery in the pre-emptive analgesia group (n=30) and following TKA surgery in the control group (n=30). POCD was defined as a two-point reduction in the postoperative score compared with the preoperative score in the mini-mental state examination. The visual analog scale (VAS) was used to evaluate the intensity of pain at rest and during exercise. The intraoperative dose of remifentanil in the pre-emptive analgesia group was significantly lower than in the control group (P<0.01). In the preemptive analgesia group, VAS scores at three days post-surgery were lower than those in the control group (P<0.01). The incidence of POCD on the third postoperative day was slightly lower in the pre-emptive analgesia group compared with the control group. In conclusion, the results demonstrate that pre-emptive analgesia by CFNB may promote the recovery of early cognitive function following TKA in elderly patients.

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.

2-Deoxy-d-glucose attenuates sevoflurane-induced neuroinflammation through nuclear factor-kappa B pathway in vitro

OBJECT

Sevoflurane, one of the most commonly used anesthetics in clinic, induced neuroinflammation and caused cognitive impairment. 2-deoxy-d-glucose (2-DG) is a synthetic analogue of glucose and is clinically used in medical imaging safely.

METHODS

We examined the effect of 2-DG on sevoflurane-induced neuroinflammation in the mouse primary microglia cells. Mouse microglia cells were treated with 4.1% sevoflurane for 6h to examine the expression of interleukin (IL)-6 and tumor necrosis factor (TNF-α) and activation of nuclear factor-kappa B (NF-κB). Pyrrolidine dithiocarbamate (PDTC) or 2-DG was used 1h before sevoflurane treatment.

RESULTS

In the present study, we found that sevoflurane increased level of IL-6 and TNF-α through activating NF-κB signaling, and that 2-DG reduced sevoflurane-induced increase in IL-6 and TNF-α and nuclear NF-κB in microglia cells.

CONCLUSION

Our data suggests that NF-κB signaling pathway could be a target for sevoflurane-induced neuroinflammation and 2-DG might be a potential therapy to prevent or treat sevoflurane-induced neuroinflammation.

[Lung cancer in the elderly: what about surgery?]

Geriatric oncology is a rapidly expanding domain because of the deep epidemiological changes of the last decades related to the ageing of the population. Lung cancer treatment in patients 75 years and over is a major issue of thoracic oncology. Curative surgery remains the treatment offering the best survival rates to the patient whatever his age. The important variability observed within the elderly forces us to take into account their specificities, in particular for ageing physiology and associated comorbidities. Thus, preoperative workup permitting to assess the resectability of the tumor but also the operability of the patient is all the more essential in the advanced age that it must be adapted to the particular characteristics of the elderly. Thanks to recent data of the literature, morbidity and mortality associated to surgical treatment are now better characterized and considered as acceptable in accordance with long-term survival. Clinical investigation remains essential to acquire a better knowledge of potential benefit of multimodal treatments in the elderly, for which very few data are available.

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.

Postoperative cognitive dysfunction in geriatric patients

Postoperative cognitive dysfunction (POCD) is a severe long-term complication after surgical procedures. POCD is mainly seen among geriatric patients. Hospitalization, extent of surgery, and systemic inflammatory response might contribute to POCD. The possible influence of the type of anesthesia is discussed. POCD is often not recognized; thus, incidence rates are likely to be underestimated (19-40%). POCD is associated with major consequences for the individual patient, e.g., delayed long-term recovery, reduced quality of life, and an increased mortality rate. Multiple risk factors have been identified over the last decade. However, the exact etiology is still unknown. This mini-review summarizes the recent developments concerning POCD prevention, diagnosis, and treatment.

Perioperative cognitive decline in the aging population

Elderly patients who have an acute illness or who undergo surgery often experience cognitive decline. The pathophysiologic mechanisms that cause neurodegeneration resulting in cognitive decline, including protein deposition and neuroinflammation, also play a role in animal models of surgery-induced cognitive decline. With the aging of the population, surgical candidates of advanced age with underlying neurodegeneration are encountered more often, raising concerns that, in patients with this combination, cognitive function will precipitously decline postoperatively. This special article is based on a symposium that the University of California, San Francisco, convened to explore the contributions of surgery and anesthesia to the development of cognitive decline in the aged patient. A road map to further elucidate the mechanisms, diagnosis, risk factors, mitigation, and treatment of postoperative cognitive decline in the elderly is provided.

Heat shock protein 72 overexpression prevents early postoperative memory decline after orthopedic surgery under general anesthesia in mice

BACKGROUND

Problems with learning and memory are common after surgery in the elderly and are associated with high morbidity. Heat shock protein 72 (Hsp72) confers neuroprotection against acute neurologic injury. We hypothesized that overexpression of Hsp72 would prevent the development of postoperative memory loss.

METHODS

C57BL/6 wild-type and Hsp72 overexpressing transgenic mice were randomly allocated to the following: control, isoflurane anesthesia alone, or tibial fracture during isoflurane anesthesia. Animals were trained 24 h before surgery using a fear conditioning protocol and assessed in their training environment and in a novel context on posttreatment days 1, 3, and 7. Microglial activation was assessed by immunostaining.

RESULTS

Adult male C57BL/6 wild-type mice exhibited reduced memory evidenced by a decreased percentage freezing time on days 1 and 3 after anesthesia alone (58.8 ± 5, 46.5 ± 5 mean ± SEM) and after surgery (53.4 ± 6, 44.1 ± 7), compared with controls (78.8 ± 5, 63.4 ± 6; P < 0.05 and P < 0.001, respectively). Hsp72 mice showed no difference by treatment on any day. Similarly, nonhippocampal-dependent memory was significantly impaired on days 1 and 3 after surgery and day 3 after anesthesia. The genotype effect was significant on days 1 and 7. CD68-immunopositive activated microglia in the hippocampus varied modestly with subregion and time; on day 7, there was a significant treatment effect with no genotype effect, with more activated microglia after surgery in all regions.

CONCLUSION

Hsp72 overexpression is associated with prevention of postoperative hippocampal-dependent and -independent memory deficit induced by anesthesia and/or surgery. Memory deficit is not correlated with numbers of activated hippocampal microglia.

[Perioperative fluid management: an analysis of the present situation]

Optimal perioperative fluid management is still controversial. Besides well known perioperative hypovolaemia, hypervolaemia has an influence on perioperative morbidity and mortality, particularly with regard to the patient's medical history, a reduced cardiac and pulmonal function and the operation itself. The concepts of preoperative, intraoperative and postoperative fluid administration are neither adequately validated, nor sufficiently integrated into a perioperative concept. At the present, moderate fluid administration to improve preoperative and postoperative outcome is safe in minor or medium surgical procedures. High-risk surgical patients benefit from a time-oriented or/and goal-oriented monitored fluid therapy. In the past only little attention has been concentrated on postoperative fluid management, but may be stimulated by the new concepts of fast track surgery.

The effects of surgery and anesthesia on memory and cognition

This chapter describes current findings from the research into postoperative cognitive dysfunction (POCD) following cardiac and non-cardiac surgery in older adults. The evidence suggests that a significant proportion of patients show POCD in the early weeks following surgery and anesthesia. Specific domains of cognition are affected, especially memory. Much less evidence supports the presence of POCD several months or years after surgery, suggesting that POCD may be transient. However, several methodological issues make it difficult to compare findings across studies. Increasing age is among the most consistently reported patient-related risk factor. Other factors more directly related to the surgery and anesthesia are likely to contribute to the pathogenesis of POCD, including inflammatory processes triggered by the surgical procedure. Animal studies have provided valuable findings otherwise not possible in human studies; these include a correlation between the inflammatory response in the hippocampus and the development of POCD in rodents.

Neuroinflammation and cognitive function in aged mice following minor surgery

Following surgery, elderly patients often suffer from postoperative cognitive dysfunction (POCD) which can persist long after physical recovery. It is known that surgery-induced tissue damage activates the peripheral innate immune system resulting in the release of inflammatory mediators. Compared to adults, aged animals demonstrate increased neuroinflammation and microglial priming that leads to an exaggerated proinflammatory cytokine response following activation of the peripheral immune system. Therefore, we sought to determine if the immune response to surgical trauma results in increased neuroinflammation and cognitive impairment in aged mice. Adult and aged mice underwent minor abdominal surgery and 24h later hippocampal cytokines were measured and working memory was assessed in a reversal learning version of the Morris water maze. While adult mice showed no signs of neuroinflammation following surgery, aged mice had significantly increased levels of IL-1beta mRNA in the hippocampus. Minor surgery did not result in severe cognitive impairment although aged mice that underwent surgery did tend to perseverate in the old target during reversal testing suggesting reduced cognitive flexibility. Overall these results suggest that minor surgery leads to an exaggerated neuroinflammatory response in aged mice but does not result in significantly impaired performance in the Morris water maze.

Surgical management of oncogeriatric patients

Major changes are taking place at a great pace in modern medicine, and surgical oncologists are at the forefront when new skills are to be tested and implemented. Perhaps the most significant change we are facing relates to the aging of our population, with most solid tumors presenting at age 70 years (+/- 5 years). The demographics and epidemiological details are covered in the appropriate sections of this special issue, but it is important to realize how such a shift influences our day-to-day practice. These principally are occurring in improved anesthetic care, minimally invasive surgery, nonoperative therapies, risk assessment, and quality-of-life estimates.

Alzheimer’s Disease: Halothane Induces Aβ Peptide to Oligomeric Form—Solution NMR Studies

Alzheimer's disease (AD) is a significant contributor to cognitive decline and is responsible for about half of the cases of dementia in later life. Although exact etiology of AD is not known, however, many risk factors for AD are identified. Anesthesia for elderly patients is considered as a risk factor in AD as they frequently experience deterioration in cognitive function with long exposure to anesthetics during surgery. Inhaled anesthetic agents remain the mainstay for patients undergoing major surgical operations. This study using multidimensional NMR spectroscopy provides the first direct evidence in vitro that inhaled anesthetic, halothane specifically interacts with Abeta40 and Abeta42 peptide. Halothane induces structural alternation of Abeta peptide from soluble monomeric alpha-helical form to oligomeric beta-sheet conformation, which may hasten the onset of AD. Abeta42 is more prone to oligomerization compared to Abeta40 in the presence of halothane. The molecular mechanism of halothane induced structural alternation of Abeta peptide is discussed.

Postoperative Cognitive Dysfunction After Cardiac Surgery

Prolonged postoperative cognitive dysfunction (POCD) is reported to occur frequently after cardiac surgery. However, it is rarely assessed in routine clinical practice and receives little attention. Although the cerebral consequences of cardiopulmonary bypass have been measured clinically, insights into the resulting molecular and pathologic events within the brain have only begun to be investigated. POCD is likely to impair quality of life and constitutes a large burden on society when elderly patients prematurely lose their independence. Numerous studies have reported that neurocognitive deficit is associated with heightened mortality, increased length of hospital stay, and discharge to a nursing home. This is linked with a tremendous demand for health-care resources. Because of the magnitude of the clinical problem, serious consideration must be directed toward understanding its etiology and the development of neuroprotective strategies. Clearly identifying the mechanisms of POCD is challenging. The purpose of this review is to discuss recent developments in our understanding of the pathophysiologic mechanisms, prevention, and treatments that have been designed to ameliorate brain dysfunction after cardiac surgery.

[Pharmacological peculiarities and problems with older patients]

Because of demographic developments, the fraction of the German population over 65 years of age in the year 2025 will have risen to 20% and will continue to rise so that in 2030 this number will have doubled compared to today's numbers. This has a huge impact on the requirements for anaesthesiologic procedures. In addition to the frequent multi-morbidity in this age group, physiologic changes also occur in the elderly which have to be taken into consideration during the entire perioperative management of these patients. Renal, cardiovascular and hepatic function are impaired in many elderly patients. A major concern in addition to cardiovascular and operative complications is the postoperative cognitive dysfunction (POCD), not only because of its implications for the patient but also because of economical consequences. Regional anaesthesia has some benefits when compared to general anaesthesia as it leads to a reduction in thromboembolic and respiratory complications.