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Preoperative assessment
Published in Brian J Pollard, Gareth Kitchen, Handbook of Clinical Anaesthesia, 2017
Delirium is an acute onset of disturbed mental function characterised by fluctuating consciousness and impaired attention. It is a common complication in older patients undergoing major surgery and is associated with prolonged length of stay and increased mortality. Postoperative cognitive dysfunction is cognitive impairment detected on neuropsychological testing following surgery. Awareness of the risk factors associated with deterioration in cognitive function following surgery allows high risk patients to be identified and strategies targeted to reduce risk. Risk factors for perioperative delirium are described in Table 25.12.
Dementia Associated with Medical Conditions
Published in Marc E. Agronin, Alzheimer's Disease and Other Dementias, 2014
Several studies have found that a significant number of older surgical patients suffer from postoperative cognitive dysfunction or POCD both acutely as well as within three to six months of surgery, characterized by discrete declines in attention, verbal and visual memory, language, and executive function. The exact percentages of POCD have varied widely, influenced by age and type of surgery, but have ranged between 5% and over 50% of patients who were evaluated three to six months postoperatively (Evered, Scott, Silbert, & Maruff, 2011; Monk et al., 2008). There has been even greater concern in the medical literature over findings of cognitive impairment associated with coronary-artery bypass grafting or CABG, performed on a half-million Americans every year. Mild impairment in memory processing, mathematical ability, complex planning, attention, and mood regulation have been seen in a significant number of post-CABG individuals, with older and more medically compromised individuals at greatest risk. One longitudinal study found POCD upon discharge in 53% of post-CABG patients, which decreased to 36% at six weeks and 24% at six months, but then rose to 42% when seen for follow-up five years later (Newman et al., 2001). Even taking into consideration the natural rate of dementia, rates in the post-CABG group were two to three times greater than expected.
Geriatrics
Published in Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor, Manual of Neuroanesthesia, 2017
As age increases, there is decrease in brain volume (4% every year), dopamine levels (10% every decade), and cerebral metabolic rate in the brain. At the same time, there is an increase in blood–brain barrier permeability, increase in arterial wall thickness, and increase in monoamine oxidase activity. All these changes occur after 40 years of age. As there is reduction in brain volume, it is more loss in the white matter than the gray matter. There is decrease in memory of the episodic type.3 As dopamine and serotonin levels decline during old age, cognitive and motor performances also decrease. As monoamine oxidase increases during old age, it causes more release of free radicals from reactions that exceed the antioxidant reserves of the brain leading to cell damage. As the blood–brain barrier permeability increases with age, it allows inappropriate passage of mediators from the plasma into the brain, leading to increased inflammatory response and structural damage to the brain. The denseness of the capillaries decreases and intimal thickness increases with age (from the fifth decade of life) in the brain, leading to increase in vascular resistance, and decrease in perfusion pressure, thereby decreasing neurocognitive function. There is progressive decline in central nervous system (CNS) activity and loss of neurons in cerebral cortex, leading to decrease in slow-wave sleep (stage 4), susceptibility to delirium (<1 month), nocturnal respiratory dysfunction (sleep apnea syndrome), Alzheimer's syndrome, dementia, and global cognitive impairment. All these changes lead to increase in the prevalence of postoperative cognitive dysfunction and delirium after anesthesia.
Postoperative cognitive dysfunction and the possible underlying neurodegenerative effect of anaesthesia
Published in International Journal of Neuroscience, 2019
Mona Hussein, Wael Fathy, Tamer Nabil, Rehab Abd Elkareem
Much Concern has been raised about postoperative cognition dysfunction (POCD) after both cardiac and non-cardiac surgery [1,2]. POCD has been widely observed in patients with major surgery, especially in those elderly patients [3]. The age has been repeatedly verified as an important risk factor for the development of neurological disorder [4]. Such postoperative cognitive dysfunction can be mild and only diagnosed by psychometric assessment [5] and sometimes it may have serious consequences on the patient’s ability to work [6]. The incidence of POCD in old patients (>60 years) undergoing non-cardiac surgery is reported to be as high as 25.8 at 1 week and 9.9% at 3 months by the International Study of Postoperative Cognitive Dysfunction (ISPOCD) [7]. Postoperative cognitive dysfunction may manifest as impairment in attention, memory, executive functions or language. Most of these cognitive changes are temporary with resolution in between six weeks and six months following the operation, which ultimately minimising medical attention on the importance of such transitory cognitive deficits on the quality of life of the patient. Even if transient, these cognitive deficits can delay the patient's recovery and, when long-term, compromise the patient’s return to their activities [8,9].
GABA(A) receptor-targeted drug development -New perspectives in perioperative anesthesia
Published in Expert Opinion on Drug Discovery, 2019
Bernd Antkowiak, Gerhard Rammes
After surgery and anesthesia, a large proportion of patients exhibits reduced cognitive performace [12]. Postoperative cognitive dysfunction is multifactorial, but long-lasting increases in the expression of α5-GABAA receptors may play an important role [111,112]. These receptors are present in the hippocampus at high densities and their role in hippocampal learning and memory is well established. Furthermore, α5-GABAA receptors are contributing to the amnestic properties of anesthetic drugs [113]. Based on these observations, it is hypothesized that negative allosteric modulators (NAMs), acting selectively on α5-GABAA receptors, should enhance cognition. One of the first ligands of this type was L-655708, a NAM with high affinity for α5-GABAA receptors. This compound enhanced performance of mice in the Morris water maze, providing proof of principle that agents, which are capable to reduce the function of these receptors, may restore memory deficits [114]. In further investigations, novel compounds were characterized, that selectively acted as NAMs on α5-GABAA receptors [115–118]. These studies demonstrated the drugs’ potential to enhance cognitive performance without anxiogenic or pro-convulsive activity. However, other studies indicated beneficial cognitive effects of drugs acting as PAMs on α5-GABAA receptors, pointing to a complex bidirectional modulation of cognition by α5- receptors [119].
Rationale, methods, and progress of the ArthroCaP Study: A prospective cohort study exploring the associations between chronic postsurgical pain and postoperative cognitive dysfunction after elective knee or hip arthroplasty
Published in Canadian Journal of Pain, 2022
Maram Khaled, Jocelyn Kuber, Mary Ferber, Praveen Sritharan, Yarden Levy, Suzanna Becker, Margaret Fahnestock, Meridith Griffin, Kim Madden, Harsha Shanthanna, Maura Marcucci
When asked about their fears related to undergoing major surgery with general anesthesia, people across different ages indicate “brain damage” and “memory loss” as main concerns much more frequently than perioperative death.53 Moreover, the literature shows that even with only a partial understanding of the concept of likelihood, most older people would not choose a treatment when the expected outcome is survival associated with cognitive and functional impairment.54,55 Persistent postoperative cognitive dysfunction is highly prevalent in older people undergoing surgery; CPSP can also occur in older surgical patients. Both of these conditions are associated with reduced autonomy and increased burden to patients, caregivers, and health care systems.