Intraoperative EEG Monitoring and Postoperative Delirium in Elderly Patients With Sevoflurane Anesthesia

Study Overview
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Brief Summary
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Delirium is an acute onset of attentional and cognitive impairment. BIS guided anesthesia can reduce the incidence of postoperative delirium. Long term electroencephalogram (EEG) suppression during operation is related to postoperative delirium. The latest research shows that the anesthesia depth guided by EEG does not reduce the incidence of postoperative delirium. The purpose of this study was to explore the relationship between anesthesia exposure with different minimum alveolar concentration(MAC) and postoperative delirium(POD), and to observe the characteristics of EEG.

Detailed Description
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More and more studies have focused on the relationship between EEG inhibition and postoperative delirium in general anesthesia. At present, there are two kinds of commonly processed quantitative EEG monitoring to evaluate the depth of anesthesia, one is bispectral index (BIS) and the other is patient state index (PSI). The relationship between intraoperative anesthetic exposure and postoperative delirium is unclear, or whether potential patient characteristics increase the risk of EEG suppression and postoperative delirium. Gastrointestinal surgery can lead to long-term changes in colonic flora, which can remotely regulate brain function through the gut brain axis. We speculated that the abnormal composition of intestinal flora before abdominal operation might be the influencing factor of POD.

Official Title
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Effects of Different Sevoflurane Concentrations on Intraoperative EEG and Postoperative Delirium in Elderly Patients

Conditions
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Postoperative Delirium, Sevoflurane, Electroencephalogram

Intervention / Treatment
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* Drug: Low MAC
* Drug: High MAC


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical diagnosis of gastrointestinal diseases Patients were aged 60 to 90 years American Society of Anesthesiologists (ASA) risk classification II-IV Patients were scheduled to undergo elective major abdominal operation(with a anticipated time of 2-6 h) Exclusion Criteria: Preoperative dementia or cognitive impairment Mental instability or mental illness Patients with any factors affecting cognitive assessment, such as language, vision and hearing impairment Any cerebrovascular accident occurred within 3 months, such as stroke etc Previous history of delirium Known hypersensitivity to sevoflurane or history of malignant hyperthermia Abuse of narcotic sedative and analgesic drugs Those who have reoperation within 7 days after operation

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: light general anesthesia<br>During anesthesia maintenance, patients were received with low concentration sevoflurane to maintain a target of 0.8 MAC. | Drug: Low MAC<br>* To maintain a target of sevoflurane inhalation concentration 0.8 MAC.<br>|
| Experimental: deep general anesthesia<br>During anesthesia maintenance, patients were received with high concentration sevoflurane to maintain a target of 1.0 MAC. | Drug: High MAC<br>* To maintain a target of sevoflurane inhalation concentration 1.0 MAC.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of POD | Incidence of POD after surgery | The 1st day after the surgery | 
| Incidence of POD | Incidence of POD after surgery | The 2nd day after the surgery | 
| Incidence of POD | Incidence of POD after surgery | The 3rd day after the surgery | 
| Incidence of POD | Incidence of POD after surgery | The 5th day after the surgery | 
| Incidence of POD | Incidence of POD after surgery | The 7th day after the surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EEG burst inhibition | Frequency of EEG burst inhibition | During surgery | 
| EEG burst inhibition | Duration of EEG burst inhibition | During surgery | 
| Incidence of adverse events | Incidence of adverse events after surgery | 30-day after surgery | 
| length of stay | length of stay after surgery | From 1st day after the surgery to 2 weeks | 
| 30-day mortality | 30-day mortality after surgery | 30-day after surgery |