Objective:Cognitive change affecting patients after anesthesia and surgery has been recognised for more than 100 yr. Research into cognitive change after anesthesia and surgery accelerated in the 1980s when multiple studies utilised detailed neuropsychological testing for assessment of cognitive change after cardiac surgery. This body of work consistently documented decline in cognitive function in elderly patients after anaesthesia and surgery, and cognitive changes have been identified up to 7.5 yr afterward. Importantly, other studies have identified that the incidence of cognitive change is similar after non-cardiac surgery. Other than the inclusion of non-surgical control groups to calculate postoperative cognitive dysfunction, research into these cognitive changes in the perioperative period has been undertaken in isolation from cognitive studies in the general population. This study aimed to develop similar terminology to that used in cognitive classifications of the general population for use in investigations of cognitive changes after anesthesia and surgery.Participants and Methods:A multispecialty working group followed a modified Delphi procedure with no prespecified number of rounds comprised of three face-to-face meetings followed by online editing of draft versions. Two major classification guidelines [Diagnostic and Statistical Manual for Mental Disorders, fifth edition (DSM-5) and National Institute for Aging and the Alzheimer Association (NIA-AA)] are used outside of anesthesia and surgery and may be useful for the inclusion of biomarkers in research. For clinical purposes, it is recommended to use the DSM-5 nomenclature.Results:The working group recommends that 'perioperative neurocognitive disorders (PND)' be used as an overarching term for cognitive impairment identified in the preoperative or postoperative period. This includes cognitive decline diagnosed before operation (described as neurocognitive disorder); any form of the acute event (postoperative delirium) and cognitive and functional decline diagnosed up to 30 days after the procedure (delayed neurocognitive recovery (dNCR)) and up to 12 months (postoperative neurocognitive disorder (postoperative NCD).1 Further, the working group has undergone a further Delphi process to expand these recommendations for research purposes which will also be covered.Conclusions:Perioperative neurocognitive disorders are the most common complication for patients aged 65y or more undergoing anesthesia and surgery. Moreover, they are associated with significant morbidity, mortality, loss of functional independence and extreme economic costs. A multi-disciplinary approach to PND, including neuropsychologists, is critical to reducing and preventing these disorders. Evered L, Silbert B, Knopman DS, et al. Recommendations for the nomenclature of cognitive change associated with anaesthesia and surgery-2018. Br J Anaesth 2018; 121: 1005-12

BACKGROUND Chronic post-surgical pain (CPSP) represents a significant issue for many patients following surgery; however, the long-term incidence and impact have not been well described following cardiac surgery. Our aim was to characterize CPSP at least 5 years following coronary artery bypass grafting (CABG) surgery. METHODS This prospective observational study investigated a cohort of patients from a larger trial investigating cognitive outcomes following CABG surgery, with 89 of 148 eligible patients (60.1%) assessed for CPSP at a mean (standard deviation [SD]) of 6.8 [1.2] years. Questionnaires interrogated pain presence, intensity, location, neuropathic characteristics, Geriatric Depression Scale scores (GDS) and instrumental activities of daily living (IADL). RESULTS CPSP was described in 21/89 (23.6%), with 10 rating it as moderate to severe. Six of the CPSP patients (29%) met criteria for neuropathic pain (6.7% overall). The highest rate of CPSP was associated with the leg surgical site (chest 12/89 [13.5%], arm 8/68 [11.8%] and leg (saphenous vein graft-SVG) 11/37 [29.7%]; χ2  = 6.523, p = 0.038). IADL scores were significantly lower for patients with CPSP (mean [SD]: 36.7 [1.6] vs. no CPSP 40.6 [0.6]; p = 0.006). Patients had GDS scores consistent with moderate depression (GDS >8) in 3/21 (14.3%) with CPSP, versus 3/68 (4.4%) non-CPSP patients (χ2  = 3.20, p = 0.073). CONCLUSIONS This study identified a CPSP incidence of 23.6% at a mean of 6.8 years after CABG surgery, with the highest pain proportion at SVG harvest sites. CPSP was associated with neuropathic pain symptoms and had a significant impact on IADLs. This emphasizes the need for long-term follow-up of CABG patients. SIGNIFICANCE This study highlights the impact of CPSP 7 years following cardiac surgery and highlights the effect of surgical site, neuropathic pain and the importance of including pain assessment and management in the long-term follow-up of cardiac surgical patients. Strategies to address and prevent chronic pain following cardiac surgery should be further explored.

Healthcare for the older patient is increasingly shifting from being supportive to providing active interventions to improve quality of life in addition to increasing longevity. For anaesthetists and peri-operative physicians, this means that a growing number of our patients presenting for anaesthesia and surgery will be elderly. It is immaterial whether this is defined as over 65 years or over 70 – what is relevant is that age-related cognitive decline is going to be present to some extent in a substantial proportion of our patients. In elective hip joint arthroplasty patients, 33.7% have pre-existing cognitive impairment; in coronary artery surgery patients this is likely over 50% 1, 2. The implication is that, just as we now screen for cardiac disease, we must do the same for patients with, or at risk of, cognitive decline. Cognitive impairment is highly prevalent in our ageing community. Population studies reveal that 16% of dementia-free individuals aged over 70 years will have mild cognitive impairment 3, which is a condition diagnosed based on criteria defined in the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) 4. As individuals age and morbid conditions increase, so does the prevalence of mild cognitive impairment. Although not associated with a functional impact on daily life (as measured by Instrumental Activities of Daily Living), mild cognitive impairment is associated with measurable cognitive impairment and a memory concern (a subjective memory complaint by the individual, informant or clinician). Importantly, it is also associated with a high risk of progression to dementia (5–10% per year) and, of relevance to anaesthetic care, a higher risk of peri-operative cognitive disorders including postoperative delirium. Recognising the growing need to better care for patients with cognitive impairment in our ageing population, many countries and organisations have produced guidelines for delirium and for hospitalised patients with dementia, but few have focused on peri-operative patients. This is a significant gap. In the UK, the National Institute for Health and Care Excellence (NICE) has produced a draft for consultation on dementia care 5, which although it mentions hospitalisation, does not address anaesthesia and surgery. There is a European Collaboration on Dementia 6 which is focused on research and community care. In Australia, there are national Delirium Clinical Care Standards 7 and a specific set of documents relating to care for patients with cognitive impairment in hospital 8; however, neither of these directly address nor identify peri-operative pathways, in fact they barely mention anaesthesia or surgery. In the US, the Alzheimer's Association has produced a number of guidelines for patients with dementia and delirium, but little content is specifically targeted at peri-operative care. In contrast, the American Society of Anesthesiologists has undertaken the Brain Health Initiative to specifically address the issue of delirium and cognitive decline associated with the peri-operative period 9. The gap in communication and understanding between anaesthetists, surgeons (or peri-operative physicians) and other disciplines and medical specialties that care for older patients with cognitive impairment is slowly being narrowed. Delirium as a specific postoperative concern has rightly been considered widely in the literature in recent years, with recommendations generally focusing on ‘bundles’ of care as supported by the Hospital Elder Life Program (HELP) initiatives 10. Despite this, many clinicians rely on pharmacological interventions which have been shown to be ineffective, and may in fact be deleterious 11. The broader area of concern regarding patients with pre-existing cognitive impairment is less well addressed. In 2012, a Professional Interest Area was established for peri-operative cognition and delirium with the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART) 12. The Alzheimer's Association International is the largest global organisation bringing together researchers, clinicians, and carers for Alzheimer's disease patients, and establishing a ‘peri-operative’ Professional Interest Area was a major step in bringing together anaesthetists, geriatricians, old-age psychiatrists and basic researchers in the one forum to address and progress clinical activity in this area. At almost the same time, it became apparent that concerns regarding postoperative cognitive dysfunction (POCD) in the elderly, and research regarding the impact of anaesthesia and surgery on cognition, were significantly hampered by barriers in nomenclature. Anaesthetic researchers were simply not talking the same language as psychologists, psychiatrists, and geriatricians. Postoperative cognitive dysfunction was purely a research diagnosis, with no clinical symptoms required. Thus, members of the Peri-operative Professional Interest Area and the semi-formal anaesthesia neurotoxicity community joined together to define peri-operative neurocognitive disorders in a way that was relevant to researchers, multidisciplinary clinicians and patients 13. It is timely, therefore, that in this issue of Anaesthesia, the Association of Anaesthetists is publishing a guideline statement on the peri-operative care of patients with dementia 14. The guidelines bring together recommendations from multiple sources relating to the clinical care pathway for patients undergoing anaesthesia and surgery. The guidelines are perhaps restrictively named because they also appropriately apply to patients with more subtle cognitive impairment. These guidelines are well considered and provide rationale for peri-operative care considerations. They also contain suggestions on implementation within hospitals. In our view, they should be considered by anaesthetists, surgeons, peri-operative physicians and geriatricians alike. The guidelines include some practical recommendations for anaesthetic care. Best available evidence suggests that benzodiazepines, antipsychotics and drugs with central anticholinergic activity should be avoided if possible. Avoiding excessive depth of anaesthesia (or more correctly avoiding excessive anaesthetic agent administration) is also recommended, although there still remains some controversy here regarding processed frontal EEG monitoring and the literature is inconclusive 15. A challenge is minimising opioids for postoperative analgesia and yet providing effective pain relief to avoid exacerbating distress and triggering delirium. The best anaesthetic technique to use in patients with cognitive impairment is still uncertain, and caution is recommended in translating animal data directly into clinical practice, without verification at least. Certainly, the best technique is one which provides anaesthesia while minimising physiological and psychological stress and allows for a rapid recovery of cognition. There are unfortunately a number of unmet challenges in the care of elderly patients presenting for anaesthesia and surgery. We do not yet have screening tools which are simple, quick and sensitive enough to help us identify at-risk individuals. For example, the widely used mini-mental state examination (MMSE) is best at identifying moderate to severe dementia and is not sensitive to milder forms of impairment 16. We also have gaps in our research knowledge because most studies on cognitive outcomes exclude patients if they have known or identified dementia or have linguistic communication challenges. This limits the applicability of anaesthetic and other peri-operative research findings. The population for investigation must be expanded to include the ‘actual’ community, and also to target under-represented groups such as these. Furthermore, the guidelines rightly caution against interpreting trial data using cognitive outcomes based on average group data (i.e. pooled data) rather than individual outcomes. With cognition, some patients will improve or remain unchanged (this is a desirable outcome from the procedure), so grouping these results with those patients who decline may mask a potential effect. Finally, often overlooked, but emphasised in these guidelines, are the issues of consent – both not only in terms of capacity to provide consent but also regarding the need to communicate an understanding of the risk of delirium or cognitive decline and possible development of a peri-operative neurocognitive disorder. These are relevant to informed decision making. Future work should be directed to a number of areas. The evidence base for the effectiveness of the recommended interventions needs to be established. Classic randomised trial designs may be difficult, so approaches such as step-wedge or cluster designs may be useful. Sufficiently rigorous and large clinical trials are needed to establish optimal anaesthetic techniques to minimise harm and/or maximise neuroprotection. Ultimately, the basic neuroscience of delirium and cognitive impairment needs to be elucidated so that targeted physical, physiological and pharmacological interventions and preventive strategies can be developed. Due to large gaps in the literature, these guidelines are not heavily evidence-based. Thus, in the meantime, while we gather better data, we must utilise documents such as the Association of Anaesthetists guideline statement on the peri-operative care of patients with dementia 14 to improve our awareness and enhance team-based care for older patients presenting for anaesthesia and surgery. We are probably decades behind where we are with our peri-operative assessment and management of patients with cardiac disease, but neurocognitive recovery is critical to successful outcomes for older patients. There is much work still to be done in this important area. LE was consulted during the development of the guidelines 14. No other competing interests declared.

It is unknown if the type of general anaesthetic used for maintenance of anaesthesia affects the incidence of postoperative cognitive dysfunction (POCD). The aim of this study was to compare the incidence of POCD in patients administered either sevoflurane or propofol for maintenance of anaesthesia during total hip replacement surgery. Following administration of a spinal anaesthetic, patients received either sevoflurane (n=121) or propofol (n=171) at the discretion of the anaesthetist for maintenance of general anaesthesia to maintain the processed electroencephalogram (bispectral index, BIS) under 60. POCD was assessed postoperatively at day 7, three months, and 12 months using a neurocognitive test battery. There was no statistically significant difference between the incidence of POCD at any timepoint with sevoflurane compared to propofol. The mean BIS was significantly lower in the sevoflurane group than in the propofol group (mean BIS 44.3 [standard deviation, SD 7.5] in the sevoflurane group versus 53.7 [SD 8.1] in the propofol group, P=0.0001). However, there was no statistically significant association between intraoperative BIS level and the incidence of POCD at any timepoint. Our results suggest that the incidence of POCD is not strongly influenced by the type of anaesthesia used in elderly patients.

1St. Vincent's Hospital Melbourne/University of Melbourne, Dept of Anaesthesiology, Melbourne, Australia, 2National Ageing Research Institute, Psychogeriatrics, Melbourne, Australia

Introduction: Ablation (RFA) for atrial fibrillation (AF) is a highly effective therapy, however carries a 0.5–1% risk of cerebral embolism and 10–20% risk of silent cerebral infarction. Whether neurocognitive dysfunction also occurs is not well established. Methods: Ninety pts undergoing RFA for AF (PAF = 60; PeAF = 30) and 30 pts with SVT were compared to control pts with AF (n = 30) awaiting RFA. Neurocognitive testing (NCT) was performed at three timepoints: Baseline pre-procedure; Day 2 (D2); and Day 90 (D90) post-procedure. NCT included eight tests from the Canadian Study of Health and Aging. Control AF pts were tested at the same timepoints. Post-operative cognitive dysfunction (POCD) was identified using the reliable change index (RCI), defined in a pt when RCI score was <−1.96 on ≥2 tests and/or combined z score was <−1.96. Results: Control and AF/SVT pts were well matched (Table). No clinical embolic events occurred with RFA. Incidence of POCD was significantly higher in PAF/PeAF compared to SVT at D2 and D90 (Table). On univariate analysis increasing LA access time and PeAF were associated with POCD at D2 (p = 0.02) and D90 (p = 0.03) Conclusions: AF RFA is associated with a 13–20% incidence of POCD in AF pts at long-term follow up. These results were seen in CHADS2 0–1 pts who represent the majority of pts undergoing AF RFA. The long-term implications of these changes require further study and may be an important determinant of procedural safety.Tabled 1PAFPeAFSVTAF ControlpAge (y)57 ± 953 ± 1056 ± 1153 ± 9NSCHADS20.8 ± 0.80.7 ± 0.90.7 ± 0.70.6 ± 0.8NSLA access time (min)159 ± 35166 ± 4292 ± 45N/A0.0007DCR (n)0.3 ± 0.81.4 ± 1.20 ± 0N/A<0.0001ACT (s)312 ± 31311 ± 20170 ± 32N/A<0.0001POCD (D2)17/60 (28%)8/30 (27%)4/30 (13%)0/30 (0%)0.04POCD (D90)8/60 (13%)6/30 (20%)1/30 (3%)0/30 (0%)0.04 Open table in a new tab

It has long been observed that some patients suffer a significant cognitive impact following anesthesia and surgery. This should not be surprising when considering that not only is the target organ for general anesthetic agents the brain itself but also that the process of anesthesia is a form of deep, pharmacologically induced coma rather than “sleep.” The expectation that such a process should be fully reversible with transient neurophysiological effects contradicts our experience with repeated abuse of other central nervous system depressants such as glue, petrol, and alcohol. Of great concern is that, while approximately 10% of populations in developed countries undergo anesthesia and surgery of some form each year, the proportion of the elderly making up this group is much greater. In addition, it is the elderly who are potentially at a greater risk of cognitive impairment following such procedures because many have decreased cognitive reserve, either due to pre-existing mild cognitive impairment (MCI) or frank dementia, which may be diagnosed or unknown. The impact of anesthesia on these individuals is poorly understood, as are the implications of the emerging laboratory data that suggest an effect of anesthetic agents on the pathological processes of Alzheimer's Disease (AD) itself.

Introduction: Cerebral microembolism occurs as a consequence of pulmonary vein isolation (PVI). However, the composition of these emboli has not been described. We sought to characterise the proportion of solid and gaseous emboli during PVI. Methods: Fifty-five pts with paroxysmal (PAF) or persistent AF (PeAF) underwent PVI with multifrequency transcranial Doppler (TCD) monitoring. Microembolic signals (MES) were classified as either gaseous or solid depending on the difference between the embolus-to-blood ratio at 2.5-MHz and 2.0-MHz insonation frequencies. MES count was performed with the machine automatic count band differentiation. Results: Mean age was 56y ± 9 (P = NS). MES were detected in all pts, with median MES count 261 (IQR 303). 71% of MES were detected during RF ablation; 24% during transeptal puncture; and 5% during mapping. Gaseous and solid MES accounted for 89% and 11% of total signals, respectively. There was no difference in MES count or composition between PAF and PeAF pts (Table). Type of AF, number of cardioversions, AF/SR during ablation, CHADS2 score, and age were not predictive of increased MES count. No pt experienced a clinical embolic event. Conclusions: MES in PAF and PeAF pts undergoing PVI are primarily gaseous. Solid events comprise a small but significant proportion of MES, and occur in the absence of overt neurologic complication. These MES may be responsible for silent cerebral microinfarction and subtle neurocognitive sequelae associated with PVI.Tabled 1PAF (n = 37)PeAF (n = 18)pTotal MES (median, IQR)234 (397)299 (266)NSGaseous MES (median, IQR)221 (374)254 (234)NSSolid MES (median, IQR)30 (47)29 (40)NSLA access time (mins)159 ± 45175 ± 42NSAblation time (min)49 ± 1858 ± 24NSCardioversions (n)0.3 ± 1.11.5 ± 2.30.02 Open table in a new tab

OBJECTIVE:To measure cognition in patients before and after coronary angiography.DESIGN:Prospective observational cohort study.SETTING:University teaching hospital.PATIENTS:56 patients presenting for elective coronary angiography.MAIN OUTCOME MEASURES:Computerised cognitive test battery administered before coronary angiography, before discharge from hospital and 7 days after discharge. A matched healthy control group was used as a comparator.RESULTS:When analysed by group, coronary angiography patients performed worse than matched controls at each time point. When the cognitive change was examined for each individual, of the 48 patients tested at discharge, 19 (39.6%) were classified as having a new cognitive dysfunction, and of 49 patients tested at day 7, six (12.2%) were classified as having a new cognitive dysfunction.CONCLUSIONS:The results confirm that cognitive function is decreased in patients who have cardiovascular disease. Furthermore, coronary angiography may exacerbate this impaired cognition in some patients.

BACKGROUND:Surgery for intracranial aneurysm often results in postoperative neurologic deficits. We conducted a randomized trial at 30 centers to determine whether intraoperative cooling during open craniotomy would improve the outcome among patients with acute aneurysmal subarachnoid hemorrhage. METHODS:A total of 1001 patients with a preoperative World Federation of Neurological Surgeons score of I, II, or III ("good-grade patients"), who had had a subarachnoid hemorrhage no more than 14 days before planned surgical aneurysm clipping, were randomly assigned to intraoperative hypothermia (target temperature, 33 degrees C, with the use of surface cooling techniques) or normothermia (target temperature, 36.5 degrees C). Patients were followed closely postoperatively and examined approximately 90 days after surgery, at which time a Glasgow Outcome Score was assigned. RESULTS:There were no significant differences between the group assigned to intraoperative hypothermia and the group assigned to normothermia in the duration of stay in the intensive care unit, the total length of hospitalization, the rates of death at follow-up (6 percent in both groups), or the destination at discharge (home or another hospital, among surviving patients). At the final follow-up, 329 of 499 patients in the hypothermia group had a Glasgow Outcome Score of 1 (good outcome), as compared with 314 of 501 patients in the normothermia group (66 percent vs. 63 percent; odds ratio, 1.14; 95 percent confidence interval, 0.88 to 1.48; P=0.32). Postoperative bacteremia was more common in the hypothermia group than in the normothermia group (5 percent vs. 3 percent, P=0.05). CONCLUSIONS:Intraoperative hypothermia did not improve the neurologic outcome after craniotomy among good-grade patients with aneurysmal subarachnoid hemorrhage.