The Effects of Anesthesia Depth Monitoring on Postoperative Recovery and Cognitive Functions in the Geriatric Patient Population

Geriatrik Hasta Grubunda Anestezi Derinliği Monitörizasyonlarının Postoperatif Derlenme ve Bilişsel Fonksiyonlara Etkileri

This study will be conducted on patients aged 65 and older scheduled for surgery due to lumbar or cervical disc herniation. General anesthesia is routinely used for these types of surgeries in the hospital. In patients receiving general anesthesia, anesthesia depth monitoring is performed.

As part of the study, a preoperative anesthesia evaluation will be conducted, which will include age, weight, height, comorbidities, regularly used medications, previous surgical or anesthesia experiences, nutritional habits, mental status, and daily activity levels.

On the day of surgery, upon arrival in the operating room, the following will be measured and recorded:

• Blood pressure using a non-invasive blood pressure monitor
• Heart rate and rhythm via electrocardiogram (ECG)
• Blood oxygen level with a pulse oximeter
• Anesthesia depth using a forehead-applied sensor

All monitoring procedures are non-invasive and painless. Following the placement of these monitoring devices and initial measurements, anesthesia induction and surgery will commence. Throughout surgery, blood pressure, heart rate, and brain activity will be continuously recorded. After the surgical procedure, anesthesia emergence and mental status will be assessed. Preoperative evaluation data and intraoperative recordings will be used solely for research purposes, with patient identity information remaining confidential.

Perioperative cognitive decline and delirium occur more frequently in the geriatric population undergoing surgery. International guidelines recommend monitoring anesthesia depth to reduce the risk of postoperative cognitive dysfunction. Anesthesia depth is commonly measured using non-invasive electroencephalography (EEG)-based methods, such as the Bispectral Index (BIS).

Previous studies have predominantly utilized processed EEG monitors that generate numerical values for tracking anesthesia depth. However, in this study, anesthesia depth will be monitored using both the standard numerical BIS index and the Density Spectral Array (DSA) mode, an advanced feature of the BIS device. To date, no studies have simultaneously examined BIS and DSA modes in relation to cognitive function and the recovery process.

The use of advanced monitoring techniques may serve as a valuable resource for future research, particularly in optimizing anesthetic management for geriatric patients with reduced cognitive reserve. This study aims to evaluate the effects of different intraoperative anesthesia depth monitoring approaches, including hemodynamic monitoring, numerical BIS values, and DSA functions. The primary objective is to determine the optimal anesthesia monitoring strategy that minimizes intraoperative hypotension, burst suppression, and postoperative delirium.

Inclusion Criteria:

• 65 years and older
• Elective spinal surgeries
• ASA status I-III

Exclusion Criteria:

• Emergent surgeries
• ASA status IV-V
• Prediagnosed delirium and or dementia
• Inability to give consent