Neuroprotective Effect of Low Mean Arterial Pressure on Postoperative Cognitive Deficit Attenuated by Prolonged Coronary Artery Bypass Time: A Meta-Analysis

Postoperative cognitive dysfunction: a concept analysis

BACKGROUND

Post-operative cognitive dysfunction (POCD) is a concern for clinicians that often presents post-surgery where generalized anesthesia has been used. Its prevalence ranges from 36.6% in young adults to 42.4% in older individuals. Conceptual clarity for POCD is lacking in the currently body literature. Our two-fold purpose of this concept analysis was to (1) critically appraise the various definitions, while also providing the best definition, of POCD and (2) narratively synthesize the attributes, surrogate or related terms, antecedents (risk factors), and consequences of the concept.

METHOD

The reporting of our review was guided by the PRISMA statement and the 6-step evolutionary approach to concept analysis developed by Rodgers. Three databases, including Medline, CINAHL, and Web of Science, were searched to retrieve relevant literature on the concept of POCD. Two independent reviewers conducted abstract and full-text screening, data extraction, and appraisal. The review process yielded a final set of 86 eligible articles.

RESULT

POCD was defined with varying severities ranging from subtle-to-extensive cognitive changes (1) affecting single or multiple cognitive domains that manifest following major surgery (2), is transient and reversible, and (3) may last for several weeks to years. The consequences of POCD may include impaired quality of life, resulting from withdrawal from the labor force, increased patients' dependencies, cognitive decline, an elevated risk of dementia, rising healthcare costs, and eventual mortality.

CONCLUSION

This review resulted in a refined definition and comprehensive analysis of POCD that can be useful to both researchers and clinicians. Future research is needed to refine the operational definitions of POCD so that they better represent the defining attributes of the concept.

Carotid Interventions in Patients Undergoing Coronary Artery Bypass Grafting: A Narrative Review

Simultaneous carotid artery stenosis (CS) and coronary artery disease (CAD) is a common condition among patients with several cardiovascular risk factors; however, its optimal management still remains under investigation, such as the assumption that carotid disease is causally related to perioperative stroke and that preventive carotid revascularization decrease the risk of this complication. Synchronous surgical approach to both conditions, performing carotid endarterectomy (CEA) before coronary artery bypass graft (CABG) during the same procedure, should still be considered in selective patients, in order to reduce the risk of perioperative stroke during coronary cardiac surgery. For the same purpose, staged approaches, such as CEA followed by CABG or CABG followed by CEA during the same hospitalization or a few weeks later have been described. Hybrid approach with carotid artery stenting (CAS) and CABG can also be an option in selected cases, offering a minimally invasive procedure to treat CS among patients whom CABG cannot be postponed. When carotid intervention is indicated in patients with concomitant CAD requiring CABG, a personalized and tailored approach is mandatory, especially in asymptomatic patients, in order to define the ideal surgical strategy. The aim of this paper is to summarize the current "state of the art" of the different approaches to carotid artery diseases in patients undergoing CABG.

An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery

Postoperative cognitive dysfunction is extremely prevalent following cardiac surgery. The increasing patient age and comorbidity profile increases their susceptibility to cognitive impairment. The underlying pathophysiological mechanisms leading to cognitive impairment are not clearly elucidated. Using the contemporary literature (2015-present), this narrative review has three aims. Firstly, to provide an overview of postoperative cognitive impairment. Secondly, to analyse the predominant pathophysiological mechanisms leading to cognitive dysfunction following cardiac surgery such as inflammation, cerebral hypoperfusion, cerebral microemboli, glycaemic control and anaesthesia induced neurotoxicity. Lastly, to assess the current therapeutic strategies of interest to address these pathophysiological mechanisms, including the administration of dexamethasone, the prevention of prolonged cerebral desaturations and the monitoring of cerebral perfusion using near-infrared spectroscopy, surgical management strategies to reduce the neurological effects of microemboli, intraoperative glycaemic control strategies, the effect of volatile vs. intravenous anaesthesia, and the efficacy of dexmedetomidine.

Contemporary Neuroprotection Strategies during Cardiac Surgery: State of the Art Review

Open-heart surgery is the leading cause of neuronal injury in the perioperative state, with some patients complicating with cerebrovascular accidents and delirium. Neurological fallout places an immense burden on the psychological well-being of the person affected, their family, and the healthcare system. Several randomised control trials (RCTs) have attempted to identify therapeutic and interventional strategies that reduce the morbidity and mortality rate in patients that experience perioperative neurological complications. However, there is still no consensus on the best strategy that yields improved patient outcomes, such that standardised neuroprotection protocols do not exist in a significant number of anaesthesia departments. This review aims to discuss contemporary evidence for preventing and managing risk factors for neuronal injury, mechanisms of injury, and neuroprotection interventions that lead to improved patient outcomes. Furthermore, a summary of existing RCTs and large observational studies are examined to determine which strategies are supported by science and which lack definitive evidence. We have established that the overall evidence for pharmacological neuroprotection is weak. Most neuroprotective strategies are based on animal studies, which cannot be fully extrapolated to the human population, and there is still no consensus on the optimal neuroprotective strategies for patients undergoing cardiac surgery. Large multicenter studies using universal standardised neurological fallout definitions are still required to evaluate the beneficial effects of the existing neuroprotective techniques.

Influence of Anemia on Postoperative Cognitive Function in Patients Undergo Hysteromyoma Surgery

Cognitive dysfunction is a common disease in aging population. This study aims to compare the influence of different degrees of anemia on the cognitive function of patients undergo hysteromyoma surgery. Sixty-one patients aged 18-60 years who underwent uterine fibroid surgery in the Second Affiliated Hospital of Shantou University Medical College from March 2019 to December 2020 were selected for this study. Patients were divided into three groups: group normal (Group N, patients have no anemia), group of mild anemia (Group Mi, patients have mild anemia) and group of moderate anemia (Group Mo, patients had moderate anemia). Combined spinal and epidural anesthesia were administered. Cognitive function tests were performed 1 day before the surgery and repeated at the 5th and 30th days after surgery. Peripheral venous blood samples from patients were collected before the surgery, right after surgery and at the 24th and 72nd hours after surgery. The contents of S-100β, IL-6, TNF-α and IL-1β in serum samples were determined by ELISA. It was found that there were no significant differences in general characteristics of patients among Group N, Group Mi and Group Mo (p > 0.05). Nine patients developed postoperative cognitive dysfunction after surgery, and the incidence was 14.75% (9/61). The incidence of postoperative cognitive dysfunction (POCD) was 40% in Group Mo, which was higher than that in Group N and Group Mi. The difference was statistically significant (p < 0.05). Inflammatory factors in patients with POCD were higher in post-surgery than before-surgery (p < 0.05), while there was no statistical significance in the difference of inflammatory factors of patients without POCD before and after surgery (p > 0.05). Taken together, this study suggested that moderate anemia could be a risk factor of POCD in patients undergoing hysteromyoma surgeries. This study will help surgeons developing measures for preventing the occurrence of POCD.