Although postoperative cognitive dysfunction (POCD) is well described after coronary artery bypass graft (CABG) surgery, a major concern has been that a progressive decline in cognition will ...ultimately lead to dementia. Since dementia interferes with the ability to carry out daily functions, the impact has far greater ramifications than cognitive decline defined purely by a decreased ability to perform on a battery of neurocognitive tests. The authors hypothesized that early cognitive impairment measured as baseline cognitive impairment is associated with an increased risk of long-term dementia.
The authors conducted a prospective longitudinal study on 326 patients aged 55 yr and older at the time of undergoing CABG surgery. Dementia was classified by expert opinion on review of performance on the Clinical Dementia Rating Scale and several other assessment tasks. Patients were also assessed for POCD at 3 and 12 months and at 7.5 yr using a battery of neuropsychologic tests and classified using the reliable change index. Associations were assessed using univariable analysis.
At 7.5 yr after CABG surgery, the prevalence of dementia was 36 of 117 patients (30.8%; 95% CI, 23 to 40). POCD was detected in 62 of 189 patients (32.8%; 95% CI, 26 to 40). Due to incomplete assessments, the majority (113 patients), but not all, were assessed for both dementia and POCD. Fourteen of 32 (44%) patients with dementia were also classified as having POCD. Preexisting cognitive impairment and peripheral vascular disease were both associated with dementia 7.5 yr after CABG surgery. POCD at both 3 (odds ratio, 3.06; 95% CI, 1.39 to 9.30) and 12 months (odds ratio, 4.74; 95% CI, 1.63 to 13.77) was associated with an increased risk of mortality by 7.5 yr.
The prevalence of dementia at 7.5 yr after CABG surgery is greatly increased compared to population prevalence. Impaired cognition before surgery or the presence of cardiovascular disease may contribute to the high prevalence.
A recent systematic review and meta-analysis by Wang and colleagues in the British Journal of Anaesthesia calls into question the concept that perioperative benzodiazepine administration is ...associated with development of postoperative delirium in older individuals after anaesthesia and surgery. This editorial focuses on potential bias within the systematic review and addresses major concerns surrounding benzodiazepine use in the older perioperative population.
There is a potential differential effect of sevoflurane compared with propofol on postoperative delirium and other perioperative neurocognitive disorders. More generally, there are perhaps ...differences between volatile and intravenous anaesthetic agents in their possible impact on perioperative neurocognitive disorders. Strengths and limitations of a recent study in this journal and its contribution to our understanding of the impact of anaesthetic technique on perioperative neurocognitive disorders are discussed.
Postoperative delirium is a serious complication of surgery associated with prolonged hospitalisation, long-term cognitive decline, and mortality. This study aimed to determine whether targeting ...bispectral index (BIS) readings of 50 (light anaesthesia) was associated with a lower incidence of POD than targeting BIS readings of 35 (deep anaesthesia).
This multicentre randomised clinical trial of 655 at-risk patients undergoing major surgery from eight centres in three countries assessed delirium for 5 days postoperatively using the 3 min confusion assessment method (3D-CAM) or CAM-ICU, and cognitive screening using the Mini-Mental State Examination at baseline and discharge and the Abbreviated Mental Test score (AMTS) at 30 days and 1 yr. Patients were assigned to light or deep anaesthesia. The primary outcome was the presence of postoperative delirium on any of the first 5 postoperative days. Secondary outcomes included mortality at 1 yr, cognitive decline at discharge, cognitive impairment at 30 days and 1 yr, unplanned ICU admission, length of stay, and time in electroencephalographic burst suppression.
The incidence of postoperative delirium in the BIS 50 group was 19% and in the BIS 35 group was 28% (odds ratio 0.58 95% confidence interval: 0.38–0.88; P=0.010). At 1 yr, those in the BIS 50 group demonstrated significantly better cognitive function than those in the BIS 35 group (9% with AMTS ≤6 vs 20%; P<0.001).
Among patients undergoing major surgery, targeting light anaesthesia reduced the risk of postoperative delirium and cognitive impairment at 1 yr.
ACTRN12612000632897.
William Morton introduced the world to ether anesthesia for use during surgery in the Bullfinch Building of the Massachusetts General Hospital on October 16, 1846. For nearly two centuries, the ...prevailing wisdom had been that the effects of general anesthetics were rapidly and fully reversible, with no apparent long-term adverse sequelae. Despite occasional concerns of a possible association between surgery and anesthesia with dementia since 1887 (
Savage, 1887
), our initial belief was robustly punctured following the publication in 1998 of the International Study of Post-Operative Cognitive Dysfunction ISPOCD 1 study by
Moller et al. (1998)
in The Lancet, in which they demonstrated in a prospective fashion that there were in fact persistent adverse effects on neurocognitive function up to 3 months following surgery and that these effects were common. Since the publication of that landmark study, significant strides have been made in redefining the terminology describing cognitive dysfunction, identifying those patients most at risk, and establishing the underlying etiology of the condition, particularly with respect to the relative contributions of anesthesia and surgery. In 2018, the International Nomenclature Consensus Working Group proposed new nomenclature to standardize identification of and classify perioperative cognitive changes under the umbrella of perioperative neurocognitive disorders (PND) (
Evered et al., 2018a
). Since then, the new nomenclature has tried to describe post-surgical cognitive derangements within a unifying framework and has brought to light the need to standardize methodology in clinical studies and motivate such studies with hypotheses of PND pathogenesis. In this narrative review, we highlight the relevant literature regarding recent key developments in PND identification and management throughout the perioperative period. We provide an overview of the new nomenclature and its implications for interpreting risk factors identified by clinical association studies. We then describe current hypotheses for PND development, using data from clinical association studies and neurophysiologic data where appropriate. Finally, we offer broad clinical guidelines for mitigating PND in the perioperative period, highlighting the role of Brain Enhanced Recovery After Surgery (Brain-ERAS) protocols.
For years, postoperative cognitive outcomes have steadily garnered attention, and in the past decade, they have remained at the forefront. This prominence is primarily due to empirical research ...emphasizing their potential to compromise patient autonomy, reduce quality of life, and extend hospital stays, and increase morbidity and mortality rates, especially impacting elderly patients. The underlying pathophysiological process might be attributed to surgical and anaesthesiological-induced stress, leading to subsequent neuroinflammation, neurotoxicity, burst suppression and the development of hypercoagulopathy. The beneficial impact of multi-faceted strategies designed to mitigate the surgical and perioperative stress response has been suggested. While certain potential risk factors are difficult to modify (e.g., invasiveness of surgery), others - including a more personalized depth of anaesthesia (EEG-guided), suitable analgesia, and haemodynamic stability - fall under the purview of anaesthesiologists. The ESAIC Safe Brain Initiative research group recommends implementing a bundle of non-invasive preventive measures as a standard for achieving more patient-centred care. Implementing multi-faceted preoperative, intraoperative, and postoperative preventive initiatives has demonstrated the potential to decrease the incidence and duration of postoperative delirium. This further validates the importance of a holistic, team-based approach in enhancing patients' clinical and functional outcomes. This review aims to present evidence-based recommendations for preventing, diagnosing, and treating postoperative neurocognitive disorders with the Safe Brain Initiative approach.
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