Anaesthesia is necessary in most surgical procedures. People of advanced age who may require surgery will also undergo anaesthesia. It is commonly understood that anesthetic agents break down easily and are excreted fairly rapidly from the body after surgery. However, there may be some concern about the ability of the elderly to metabolise anesthetics and to successfully pass the agents out of the body.
How Anesthesia Works
According to the Mayo Clinic general anaesthesia during surgical procedures affects aspects of the physiology of the brain, including neurotransmitters, blood flow, metabolic functions and spinal fluid. Control of neurological responses to a stimulus such as pain is very important during surgery. In many cases mechanically-assisted breathing is required due to the lack of response in the brain to triggers that tell it to send signals to the respiratory system.
According to the National Library of Medicine reports from as far back as the 1950s indicated that elderly people were experiencing problems after surgery, specifically with brain functions. The syndrome known as postoperative cognitive dysfunction (POCD) has more recently been recognised as a shared experience among anyone who undergoes anaesthesia during surgical procedures. However, POCD generally dissipates within a few weeks or more.
POCD and the Elderly
In May 2005 American Journal of Hypertension revisited a 1998 Lancet publication that reported POCD conditions lasting 3 months or more in significant numbers of elderly people who had undergone anaesthesia during surgery. An alarming finding from this study revealed that people who exhibited residual symptoms of POCD were more likely to die within one year after surgery. This was also the case for people who had a history of stroke, which is more common in the elderly than most other age groups.
Complications After Surgery Among the Elderly
According to the Merck Manuals Online Medical Library cognitive recovery among the elderly is the most commonly reported side effect as a result of surgical anaesthesia. However, it is not clear that anaesthesia is the sole reason for this condition. Prescribed post-operative pain medications can also have an effect on cognition, as can the interaction of pain medications with existing drug regimens. Another cause of cognitive difficulty can be mental stress from the procedure itself, especially in older patients.
Dementia and Delirium in Post-Operative Elderly Patients
Acute Confusional State (ACS), otherwise known as delirium, is common in elderly patients who have undergone anaesthesia or who are about to go into surgery. This disassociate syndrome may be related to unfamiliarity and discomfort with the hospital surrounding, or may be caused by preoperative procedures that include drug medications. However, delirium is most often reported in preoperative elderly patients who have a history of dementia.