Effect of remifentanil and fentanyl on postoperative cognitive function and cytokines level in elderly patients undergoing major abdominal surgery

Incidence and Factors Related to Prolonged Postoperative Cognitive Decline (POCD) in Elderly Patients Following Surgery and Anaesthesia: A Systematic Review

Aim

The aim of this systematic review is to explore the current literature to provide evidence regarding the incidence and risk factors of prolonged POCD in elderly patients following cardiac and non-cardiac surgical interventions.

Methods

The PubMed and Google Scholar databases were searched using appropriate keywords and search engines for adequate evidence from studies meeting the inclusion criteria so as to reveal the end-point, which was the presence of prolonged POCD in elderly patients following surgery and anaesthesia. The incidence of POCD at different time intervals and the variables predicting the occurrence of POCD were analysed.

Results

The results of 23 articles covering 5077 patients (3694 non cardiac and 1383 cardiac surgeries) were carefully analysed. POCD occurs from the first postoperative day and lasts for potentially long periods. The incidence of POCD in this review ranged from 2.2% to 35.7%. More specifically, it ranged from 2.2% to 31.5% in non-cardiac surgeries and 11.8% to 35.7% in patients who had undergone cardiac surgeries. Some of the independent risk factors (predictors) for the development of POCD were advanced age, high concentration of neuroinflammatory mediators detectable in plasma, low SpO2, longer anaesthetic and surgical duration, and depth of anaesthesia.

Conclusion

This review can only provide limited evidence of prolonged POCD (more than a year) and further research that involves better study designs, larger samples, involving longer follow-up, and at different sites (multicentre) is highly advised. This in turn may help researchers and clinicians to discover the actual causes and risk factors and develop appropriate preventive and treatment protocols to tackle POCD in the ageing surgical population.

Effects of qCON and qNOX-guided general anaesthesia management on patient opioid use and prognosis: a study protocol

INTRODUCTION

The adverse effects of general anaesthetic drugs (especially opioids) cannot be ignored. However, current nociceptive-monitoring techniques still lack consistency in guiding the use of opioids. This trial will study the demand for opioid use and patient prognosis in qCON and qNOX-guided general anaesthesia management.

METHODS AND ANALYSIS

This prospective, randomised, controlled trial will randomly recruit 124 patients undergoing general anaesthesia for non-cardiac surgery in equal numbers to either the qCON or BIS group. The qCON group will adjust intraoperative propofol and remifentanil dosage according to qCON and qNOX values, while the BIS group will adjust according to BIS values and haemodynamic fluctuations. The differences between the two groups will be observed in remifentanil dosing and prognosis. The primary outcome will be intraoperative remifentanil use. Secondary outcomes will include propofol consumption; the predictive ability of BIS, qCON and qNOX on conscious responses, noxious stimulus and body movements; and changes in cognitive function at 90 days postoperatively.

ETHICS AND DISSEMINATION

This study involves human participants and was approved by the Ethics Committee of the Tianjin Medical University General Hospital (IRB2022-YX-075-01). Participants gave informed consent to participate in the study before taking part. The study results will be published in peer-reviewed journals and presented at relevant academic conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2200059877.

Identification of individuals at risk for postoperative cognitive dysfunction (POCD)

Postoperative cognitive dysfunction (POCD) is common, occurring in around 10-54% of individuals within first few weeks after surgery. Although the majority of POCD is less commonly persistent later than 3 months following surgery, the condition increases length of stay (LOS), mortality and long-term cognitive decline, raising the need for a broad screening to identify individuals at risk for POCD during the perioperative period. In this narrative review, we summarize preoperative, intraoperative and postoperative risk factors for POCD reported in last 5 years and discuss neuropsychological tools and potential biomarkers and time points for assessment that might be suitable for clinical use. We aim to provide crucial information for developing a strategy of routine screening for POCD, which may assist with better identification of at-risk individuals for early interventions. Very importantly, the utilization of a standardized strategy may also allow higher consistency and comparability across different studies.

Which idea is better with regard to immune response? Opioid anesthesia or opioid free anesthesia

The stress of surgery is characterized by an inflammatory response with immune suppression resulting from many factors, including the type of surgery and the kind of anesthesia, linked with the drugs that are used and the underlying disease of the patient. The trauma of surgery triggers a cascade of reactions involving the immune response and nociception. As strong analgesics, opioids provide the analgesic component of general anesthesia with bi-directional effect on the immune system. Opioids influence almost all aspects of the immune response in regards to leukocytes, macrophages, mast cells, lymphocytes, and NK cells. The suppressive effect of opioids on the immune system is limiting their use, especially in patients with impaired immune response, so the possibility of using multimodal anesthesia without opioids, known as opioid-free anesthesia (OFA), is gaining more and more sympathizers. The idea of OFA is to eliminate opioid analgesia in the treatment of acute pain and to replace it with drugs from other groups that are assumed to have a comparable analgesic effect without affecting the immune system. Here, we present a review on the impact of anesthesia, with and without the use of opioids, on the immune response to surgical stress.

Perioperative brain health: strategies to prevent perioperative neurocognitive disorders

Cognitive changes in patients after anesthesia and surgery have been recognized for over 100 years. Research on postoperative cognitive changes accelerated in the 1980s and the term postoperative cognitive dysfunction emerged, which was used until recently. Postoperative cognitive dysfunction has been used in research to describe an objectively measurable decline in cognitive function using neuropsychological tests. This dysfunction had significant heterogeneity in the type, number of tests, timing of tests, and the criteria for change. Therefore, a recent article recommended a new nomenclature for perioperative neurocognitive disorders including neurocognitive disorder, postoperative delirium, delayed neurocognitive recovery, and postoperative neurocognitive disorder. Since old age and baseline cognitive impairment are important risk factors for these perioperative neurocognitive disorders, routine preoperative cognitive assessment in all elderly patients is recommended. A preventive strategy is important, since effective modality for the treatment of perioperative neurocognitive disorders is not yet known. Intraoperative monitoring of age-adjusted end-tidal minimal alveolar concentration fraction, electroencephalography-based anesthetic management, and perioperative non-pharmacological methods are recommended for effective prevention.

Assessment of Postoperative Cognitive Dysfunction: Results From a Survey of Turkish Anaesthesiologists

Objective

Postoperative cognitive dysfunction (POCD) is one of the most common complications in elderly surgical patients. We conducted a survey study to evaluate the perspectives of Turkish anaesthesiologists on postoperative cognitive disorders.

Methods

We conducted a prospective online survey with questions and answers were recorded either in a Likert scale from 1 to 5 (completely disagree to completely agree) or as yes/no/do not know types of answers. Potential participants were contacted through an e-mail that included a brief introductory note, instructions, a link to the survey and the authors' contact information.

Results

We analysed 129 surveys (9.9% of total potential respondents). The majority believed that the risk of cognitive side effects should be considered when choosing the type of anaesthesia (87.6%) and that preoperative cognitive function should be routinely assessed (74.4%). When caring for an agitated and confused patient postoperatively, 56.6%, protocols to screen and manage postoperative cognitive disorders were rarely used. Nearly all respondents believe that postoperative delirium and POCD are neglected areas in anaesthesiology.

Conclusion

Overall, participants perceive postoperative cognitive disorders as important adverse outcomes following surgery and anaesthesia. They are aware of the main risk factors for their development but may lack information on the prevention and management postoperatively.

Current Perspectives on Postoperative Cognitive Dysfunction in the Ageing Population

Postoperative cognitive dysfunction (POCD) is defined as a prolonged cognitive function impairment that occurs within weeks to months of a surgical procedure. It is especially prevalent in the elderly population, leading to increased morbidity and mortality. As anaesthetic and surgical care continues to improve and become increasingly safer, a significantly greater number of older patients have elective surgical procedures today, yet this comes with an increased POCD risk as they go through the perioperative phases. Although the pathophysiology behind the development of POCD is still under investigation, current causative mechanisms include the mode of anaesthesia administered, anaesthetic used, cerebral hypoperfusion, hyperventilation and neuroinflammation. These findings lend an insight into the importance of being cognisant of the higher likelihood of POCD in at-risk patients, including the elderly, and taking precautions to include preoperative and postoperative cognitive testing, careful monitoring during anaesthesia, blood pressure control and early treatment of postoperative complications as they arise. In this review, we provide an update on the current understanding of the pathophysiology leading to POCD, identifying risk factors, prevention and treatment strategies, with a specific focus on the elderly population.

Comparative effects of fentanyl versus sufentanil on cerebral oxygen saturation and postoperative cognitive function in elderly patients undergoing open surgery

This study was aimed to systematically evaluate the effects of fentanyl and sufentanil on intraoperative cerebral oxygen saturation changes and postoperative cognitive function in elderly patients undergoing open surgery. Ninety-six elderly patients who had undergone open surgery under general anesthesia were randomly divided into fentanyl group (F group, anesthesia by fentanyl, 4 g/kg) and sufentanil group (S group, anesthesia by sufentanil, 0.4 µg/kg). There were no significant differences between the F group and S group in the general characteristics of patients. Compared to the F group, the S group had a better effect on suppressing the stress response, maintaining a stable hemodynamic status and achieving better anesthesia effects. The anesthesia recovery time of the S group was significantly shorter than that of the F group. There was no significant difference between the two groups in the intraoperative and postoperative agitation. Patient's waking time and extubation time were significantly shorter in the S group than the F group. The VAS scores in the S group were significantly lower than those in the F group at each time point. The Ramsay scores in the S group were significantly higher than those in the F group at each time point. The cerebral oxygen saturation (SctO₂) levels in both groups were significantly increased following anesthesia induction and intubation compared to that of the awake state (P < 0.05), and SctO₂ was significantly decreased during the surgery in both groups. The changes in SctO₂ levels were not significantly different between the two groups (P > 0.05). The SctO₂ level was significantly higher during surgery than that after intubation. Compared with the F group, the relative value of SctO₂ decline in the S group was smaller. Compared to the day before surgery, the Montreal Cognitive Assessment (MoCA) scores of both groups were significantly reduced after surgery. At 1 day post-surgery, the MoCA scores of the S group were significantly higher and the incidence of postoperative cognitive dysfunction (POCD) was significantly lower compared to the F group. POCD occurred in three patients (6.2%) in the S group, and the ratio was significantly lower than that in the F group (11.9%) (P < 0.05). It showed a consistent trend with the SctO₂ status during the surgery. The relative value of SctO₂ decline in the S group was significantly smaller than that in the F group. The reduction of cognitive function in the S group was significantly lower than that in the F group. These results indicate that the changes in SctO₂ are a good prediction of the incidence of POCD.

Anesthetic management of geriatric patients

The number of elderly patients who frequently access health care services is increasing worldwide. While anesthesiologists are developing the expertise to care for these elderly patients, areas of concern remain. We conducted a comprehensive search of major international databases (PubMed, Embase, and Cochrane) and a Korean database (KoreaMed) to review preoperative considerations, intraoperative management, and postoperative problems when anesthetizing elderly patients. Preoperative preparation of elderly patients included functional assessment to identify preexisting cognitive impairment or cardiopulmonary reserve, depression, frailty, nutrition, polypharmacy, and anticoagulation issues. Intraoperative management included anesthetic mode and pharmacology, monitoring, intravenous fluid or transfusion management, lung-protective ventilation, and prevention of hypothermia. Postoperative checklists included perioperative analgesia, postoperative delirium and cognitive dysfunction, and other complications. A higher level of perioperative care was required for older surgical patients, as multiple chronic diseases often makes them prone to developing postoperative complications, including functional decline and loss of independence. Although the guiding evidence remains poor so far, elderly patients have to be provided optimal perioperative care through close interdisciplinary, interprofessional, and cross-sectional collaboration to minimize unwanted postoperative outcomes. Furthermore, along with adequate anesthetic care, well-planned postoperative care should begin immediately after surgery and extend until discharge.

A comparison of effects of scalp nerve block and local anesthetic infiltration on inflammatory response, hemodynamic response, and postoperative pain in patients undergoing craniotomy for cerebral aneurysms: a randomized controlled trial

BACKGROUND

The purpose of this study was to compare the effects of scalp nerve block (SNB) and local anesthetic infiltration (LA) with 0.75% ropivacaine on postoperative inflammatory response, intraoperative hemodynamic response, and postoperative pain control in patients undergoing craniotomy.

METHODS

Fifty-seven patients were admitted for elective craniotomy for surgical clipping of a cerebral aneurysm. They were randomly divided into three groups: Group S (SNB with 15 mL of 0.75% ropivacaine), group I (LA with 15 mL of 0.75% ropivacaine) and group C (that only received routine intravenous analgesia). Pro-inflammatory cytokine levels in plasma for 72 h postoperatively, hemodynamic response to skin incision, and postoperative pain intensity were measured.

RESULTS

The SNB with 0.75% ropivacaine not only decreased IL-6 levels in plasma 6 h after craniotomy but also decreased plasma CRP levels and increased plasma IL-10 levels 12 and 24 h after surgery compared to LA and routine analgesia. There were significant increases in mean arterial pressure 2 and 5 mins after the incision and during dura opening in Groups I and C compared with Group S. Group S had lower postoperative pain intensity, longer duration before the first dose of oxycodone, less consumption of oxycodone and lower incidence of PONV through 48 h postoperatively than Groups I and C.

CONCLUSION

Preoperative SNB attenuated inflammatory response to craniotomy for cerebral aneurysms, blunted the hemodynamic response to scalp incision, and controlled postoperative pain better than LA or routine analgesia.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03073889 (PI:Xi Yang; date of registration:08/03/2017).

Remifentanil suppresses increase in interleukin-6 mRNA in the brain by inhibiting cyclic AMP synthesis

PURPOSE

Neuronal inflammation is caused by systemic inflammation and induces cognitive dysfunction. IL-6 plays a crucial role in therapies for neuronal inflammation and cognitive dysfunction. Remifentanil, an ultra-short-acting opioid, controls inflammatory reactions in the periphery, but not in the brain. Therefore, the anti-inflammatory effects of remifentanil in neuronal tissue and the involvement of cAMP in these effects were investigated in the present study.

METHODS

Mice were divided into 4 groups: control, remifentanil, LPS, and LPS + remifentanil. Brain levels of pro-inflammatory cytokine mRNA, and serum levels of corticosterone, catecholamine and IL-6 were measured in the 4 groups. The co-localization of IL-6 and astrocytes in the mouse brain after the LPS injection was validated by immunostaining. LPS and/or remifentanil-induced changes in intracellular cAMP levels in cultured glial cells were measured, and the effects of cAMP on LPS-induced IL-6 mRNA expression levels were evaluated.

RESULTS

Remifentanil suppressed increase in IL-6 mRNA levels in the mouse brain, and also inhibited the responses of plasma IL-6, corticosterone, and noradrenaline in an inflammatory state. In the hypothalamus, IL-6 was localized in the median eminence, at which GFAP immunoreactivity was specifically detected. In cultured cells, remifentanil suppressed increase in IL-6 mRNA levels and intracellular cAMP levels after the administration of LPS, and this enhanced IL-6 mRNA expression in response to LPS.

CONCLUSION

Remifentanil suppressed increase in IL-6 mRNA levels in the brain in an inflammatory state, and this effect may be attributed to its direct action on neuronal cells through the inhibition of intracellular cAMP rather than corticosterone.

High doses of minocycline may induce delayed activation of microglia in aged rats and thus cannot prevent postoperative cognitive dysfunction

Objective

Postoperative cognitive dysfunction (POCD) is common after surgery in elderly patients and is associated with high morbidity. The molecular mechanisms responsible for POCD are unknown. Minocycline, an inhibitor of microglial activation, may be useful in treating and preventing POCD. We explored whether minocycline can inhibit microglial activation and prevent POCD in aged rats as a surgery model.

Methods

Rats aged 18 to 20 months were randomly allocated to the following groups: naïve, abdominal surgery alone, or minocycline injection before abdominal surgery. Hippocampal cytokine mRNA levels were measured at 3 hours, 1 day, 3 days, and 7 days after surgery, and microglial activation was measured at 3 hours and 7 days after surgery. Memory was assessed using the Morris water maze test.

Results

Surgery resulted in severe cognitive impairment in aged rats and induced a significant neuroinflammatory response and microglial activation. The use of minocycline can prevent microglial activation after surgery, but delayed microglial activation may occur. The use of minocycline may further impair memory after surgery.

Conclusion

Minocycline can restrain microglial activation and restrict the inflammatory response in the hippocampus early after surgery, but it may induce delayed microglial activation and cannot prevent POCD in aged rats.

Cognitive decline associated with anesthesia and surgery in the elderly: does this contribute to dementia prevalence?

PURPOSE OF REVIEW

To provide an update on the current state of research investigating the effects of anesthesia and surgery on cognition in the elderly, including consideration of overlap with cognitive disorders in the community.

RECENT FINDINGS

The studies reviewed here identify detrimental effects of anesthesia and surgery on cognition in a proportion of elderly individuals. Animal models demonstrate an association between anesthetic agents and Alzheimer's disease pathology. Human studies demonstrate a high incidence of cognitive impairment preoperatively in the elderly and further decline postoperatively, with recent work showing that poor preoperative cognitive function is a key predictor for further postoperative decline. Results from retrospective studies into an association between Alzheimer's disease and prior anesthesia and surgery are equivocal, but there are some data to suggest an association with accelerated cognitive decline in the long term. Postoperative delirium is common and even in individuals with normal preoperative cognition is associated with long-term decline.

SUMMARY

Cognitive impairment in the elderly ultimately leads to a decline in function with high personal and societal costs. Following anesthesia and surgery, decline in cognition is observed in some individuals, which may represent vulnerability for future decline or may alter their cognitive trajectory. Recent work suggests factors that impact this decline and/or impair recovery include higher risk patients and subtle cognitive impairment preoperatively. Identifying these individuals is critical to determining opportunities for intervention and preventive strategies, and ultimately reducing the impact on functional decline. It remains unclear if anesthesia and surgery play a role in the onset or progression of mild cognitive impairment and dementia across the community. Recent work showing that preoperative impairment is a significant risk factor for decline indicates that routinely assessing cognition preoperatively would allow improved management including referral pathways for patients at risk, delirium prevention, specifically optimizing care and consideration of treatment options.