Question about anesthestic risks in elederly

I don't have the article, but the department head where I am, quoted some research on this very topic. As a result, we use the BIS on all patients > 65 years, and try and keep it above 40, as there has been a correlation between memory loss and low BIS readings. If I remember right, there was mention of multiple anesthetics causing memory and function loss as well. I have also had patients and families complain about this, and have done hips and such under spinal anesthesia to prevent it.

Here is an article I found with a quicky search of sciencedirect.

Cognitive function after anaesthesia in the elderly


Alex Y. Bekker md, PhD, Chief of Neuroanesthesia, Associate Professor of Anesthesiology,

Edwin J. Weeks md, Assistant Professor of Anesthesiology

Department of Anesthesiology, New York University Medical Center, 560 First Avenue, IRM 605, New York, NY 10016, USA
New York University Medical Center, New York, NY, USA

Abstract

Despite advances in peri operative care, a significant percentage of elderly patients experience transient post operative delirium and/or long-term post-operative cognitive dysfunction (POCD). This chapter reviews the aetiology, clinical features, preventive strategies and treatment of these syndromes. Pre-operative, intra-operative, and post-operative risk factors for delirium and POCD following cardiac and non-cardiac surgery are discussed. It is most likely that the aetiology of delirium and POCD is multifactorial and may include factors such as age, decreased pre-operative cognitive function, general health status and, possibly, intra-operative events. Currently there is no single therapy that can be recommended for treating post-operative cognitive deterioration. Primary prevention of delirium and POCD is probably the most effective treatment strategy. Several large clinical trials show the effectiveness of multicomponent intervention protocols that are designed to target well-documented risk factors in order to reduce the incidence of post-operative delirium and, possibly, POCD in the elderly.

BTW here is another one that refutes the earlier one.

Effects of anesthesia in elective surgery on the memory of the elderly


Armando Beranta, , Varda Kaufmanb, Arthur Leibovitza, Beno Habota and Murat Baharc

Department of Geriatrics, Shmuel Harofeh Medical Center1, Beer- Yakov, Israel
b Department of Psychology, Assaf Harofeh Medical Center, Zerifn 70300, Israel
c Department of Anesthesiology, Assaf Harofeh Medical Center, Zerifin 70300, Israel


Abstract

The effects of anesthesia in elective operations on the cognitive functioning of the elderly, was examined in 88 patients aged 60–90 years. These patients were assessed pre-operatively and at a week and three months post-operatively. Forty patients (44.5%) received general anesthesia and 48 (54.5%) received regional anesthesia. The results show no significant difference between the two anesthetic methods. Differences were noted in remote memory index between the three examination time periods. (In contrast to a later work, it was found that patients whose cognitive state had been low deteriorated more than others). The only differences found between younger and older patients were in remote, recent and immediate memory. One of the major conclusions was that the effects of the methods of anesthesia, general and regional, are no different in young and elderly patients.