From the Guidelines
Patients older than 65 years, particularly those with preoperative cognitive impairment, history of delirium, lower educational level, and multiple comorbidities, are at high risk of developing cognitive impairment after general anesthesia.
Risk Factors
The risk factors for cognitive impairment after general anesthesia can be categorized into several groups, including:
- Patient-related factors: advanced age (particularly over 65 years), pre-existing cognitive impairment or dementia, lower educational level, and a history of previous postoperative delirium 1
- Medical conditions: cerebrovascular disease, diabetes, hypertension, and heart disease
- Surgical factors: longer operations, emergency procedures, and major surgeries (especially noncardiac surgery)
- Anesthesia-related factors: deeper anesthesia levels, use of certain medications, and perioperative complications like hypotension, hypoxemia, and electrolyte disturbances
- Social factors: smoking, being institutionalized, and being male, while having a higher level of education was associated with a lower risk of cognitive impairment 1
Mechanisms and Prevention
The underlying mechanisms involve neuroinflammation, oxidative stress, and disruption of neurotransmitter systems. Recognizing these risk factors allows for preoperative optimization, consideration of regional anesthesia when appropriate, careful medication selection, and implementation of enhanced recovery protocols to minimize cognitive complications.
Monitoring and Management
Processed EEG monitoring may aid in reducing the risk of adverse effects resulting from an inadequate or excessive anaesthetic dose and may reduce the risk of postoperative delirium and postoperative cognitive dysfunction 1.
Key Considerations
The risk of cognitive impairment after general anesthesia can be minimized by careful patient selection, optimization of preoperative conditions, and careful perioperative management. This includes careful consideration of the patient's age, medical history, and social factors, as well as the use of appropriate anesthesia techniques and monitoring.
From the Research
Risk Factors for Cognitive Impairment after General Anesthesia
- Prior exposure to general anesthesia may lead to prolonged cognitive impairment, with repeated exposure potentially being a risk factor for greater short-term postoperative cognitive impairment 2
- Pre-existing cognitive impairment may impart a susceptibility to further cognitive dysfunction 3
- Age, particularly being elderly, is a risk factor for postoperative cognitive dysfunction (POCD) 3, 4
- General anesthesia may induce short-term impairment of verbal memory and selective and divided attention 5
- The relationship between anesthesia exposure and the development of long-term neurocognitive disorders, such as dementia, is still debated and requires further research 3, 6
- Other potential risk factors for cognitive impairment after general anesthesia include: