Anesthesia

Unplanned hospitalizations accelerate cognitive decline in older adults

Data from the Rush Memory and Aging Project has found that emergency and urgent hospitalizations are associated with an increased rate of cognitive decline in older adults.

Non-elective hospitalizations were associated with an approximately 60% acceleration in the rate of cognitive decline from before hospitalization. Elective hospitalizations, however, were not associated with acceleration in the rate of decline at all.

Of the 930 participants (average age 81), 613 were hospitalized at least once over an average of almost five years of observation. Of those who were hospitalized, 260 (28%) had at least one elective hospital admission, and 553 (60%) had at least one non-elective hospital admission. These groups included 200 participants (22%) who had both types of hospitalizations.

The data was presented at the Alzheimer's Association International Conference in London on July 17.

https://www.eurekalert.org/pub_releases/2017-07/rumc-hac071717.php

Inflammation triggered by brain's own immune cells behind post-surgical decline

There is growing evidence that inflammation might be responsible for the cognitive decline seen in many older adults after surgery. Now a mouse study provides evidence that brain inflammation and cognitive decline following surgery are triggered by the brain's microglia.

When mice had their microglia temporarily depleted before surgery, they didn’t show any cognitive decline several days after surgery. They also had much lower levels of inflammatory molecules in the hippocampus. Controls — those not receiving the experimental drug to deplete microglia to around 5% of normal levels — did typically show a drop in cognitive performance.

Microglia levels returned to normal within two days after the treatment was stopped, and there was no sign of any impairment in surgical wound healing as a result of the intervention.

https://www.eurekalert.org/pub_releases/2017-04/uoc--cda040517.php

Delirium in older patients after surgery linked to long-term cognitive decline

A 3-year study looking at short-term and long-term cognitive decline in older patients following a surgery found that those who experienced delirium after the surgery showed significantly greater decline than those who didn’t suffer such post-surgical confusion.

The study involved 560 patients (70+), of whom 134 experienced delirium. Both groups showed a significant cognitive decline at one month, followed by a return to their previous level of cognitive function at two months and then a gradual decline for the next 34 months. However, the rate of decline over the three year follow-up was not significant for those who hadn’t experienced delirium.

Those who suffered delirium also had significantly lower cognitive function before surgery.

The odd finding that even the delirium group recovered their cognitive function at two months, before once again declining, suggests that something about the delirium triggers a cascade of events which leads to progressive, long-lasting effects.

http://www.eurekalert.org/pub_releases/2016-07/hsif-dio071416.php

Who’s more likely to develop delirium after surgery?

Delirium after surgery can lead to long-term cognitive decline in older adults — but not always. So what makes the difference?

A preliminary study involving 126 older adults suggests the answer lies in their cognitive function before surgery. Their global cognition score explained the most variation, with other significant factors including: IQCODE score, cognitive independent activities of daily living impairment, living alone, cerebrovascular disease, Charlson comorbidity index score, and exhaustion level. Taken together, these factors explained 32% of the variation in people’s outcome.

Delirium, an acute state of confusion, is a common condition affecting up to 50% of hospitalized older adults.

https://www.eurekalert.org/pub_releases/2017-03/hsif-plc031417.php

Certain leisure activities may reduce post-surgical delirium among older adults

A study of 142 older adults who underwent elective surgery found that greater participation in cognitive activities was linked with a lower incidence and lower severity of delirium.

Nearly a third of the patients (average age 71) developed post-operative delirium. Those who did had participated in fewer leisure activities before surgery compared with people who didn't experience delirium.

Out of all the activities, reading books, using email, and playing computer games reduced the risk of delirium. Playing computer games and singing were the only two activities that predicted lower severity of delirium.

The protection afforded was dose-dependent, with each additional leisure activity reducing post-operative delirium by 8%.

http://www.eurekalert.org/pub_releases/2016-06/ags-cla062116.php

http://www.eurekalert.org/pub_releases/2016-06/w-crm062216.php

Because long-term cognitive decline can occur in some older adults after undergoing surgery, there has been some concern that exposure to anesthesia may be associated with increased dementia risk. It is therefore pleasing to report that data from the very large, long-running Mayo Clinic Study, the Rochester Epidemiology Project, has found that receiving general anesthesia for procedures after age 45 is not a risk factor for developing dementia.

http://www.eurekalert.org/pub_releases/2013-05/mc-nlb042913.php

[3409] Sprung J, Jankowski CJ, Roberts RO, Weingarten TN, Aguilar AL, Runkle KJ, Tucker AK, McLaren KC, Schroeder DR, Hanson AC, et al. Anesthesia and Incident Dementia: A Population-Based, Nested, Case-Control Study. Mayo Clinic Proceedings [Internet]. Submitted . Available from: http://www.mayoclinicproceedings.org/article/S0025-6196(13)00124-9/abstract

Supporting the idea that repeated anaesthesia in children can lead to memory impairment, a rodent study has revealed that repeated anaesthesia wiped out a large portion of the stem cells in the hippocampus. This was associated with impaired memory in young animals, which worsened as they got older. The effect did not occur in adult animals. A similar effect has also been found with radiotherapy, and animal studies have found physical activity after radiotherapy results in a greater number of new stem cells that partly replace those that have been lost.

Older news items (pre-2010) brought over from the old website

Anesthesia exposure before age 3 found not to impact cognitive performance

A twin study challenges findings that receiving anesthesia at a very young age (below four) is associated with subsequent learning problems. The Dutch study involved 1,143 pairs of identical twins, and compared groups where both twins had been exposed to anesthesia before age 3, where neither had been exposed to anesthesia, or where only one member of the pair had been exposed to anesthesia. Cognitive performance at age 12 was assessed from a standardized national exam administered to all children in the Netherlands at that age. It was found that there was no difference in cognitive performance between twins where one had been exposed to anesthesia and the other had not. It therefore seems likely that the association is due to children likely to undergo surgery early in life having significant medical problems that are associated with a vulnerability to learning disabilities.

[1217] Bartels M, Althoff RR, Boomsma DI. Anesthesia and cognitive performance in children: no evidence for a causal relationship. Twin Research and Human Genetics: The Official Journal of the International Society for Twin Studies [Internet]. 2009 ;12(3):246 - 253. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19456216

http://www.eurekalert.org/pub_releases/2009-08/uov-grn080409.php

Common pediatric anesthesia drugs cause brain damage and learning and memory problems in infant rats

A new study has found that drugs commonly used to anesthetize children can cause brain damage and long-term learning and memory disturbances in infant rats. The rats appeared to behave normally in most other ways, and there were no outward signs of brain damage.

[207] Jevtovic-Todorovic V, Hartman RE, Izumi Y, Benshoff ND, Dikranian K, Zorumski CF, Olney JW, Wozniak DF. Early Exposure to Common Anesthetic Agents Causes Widespread Neurodegeneration in the Developing Rat Brain and Persistent Learning Deficits. J. Neurosci. [Internet]. 2003 ;23(3):876 - 882. Available from: http://www.jneurosci.org/cgi/content/abstract/23/3/876

http://www.eurekalert.org/pub_releases/2003-02/wuso-cpa013003.php