Evaluation of Equivalent Minimum Alveolar Concentration (eMAC) During Propofol/Remifentanil Anesthesia

Study Overview
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Brief Summary
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The aim of this study is to verify the accuracy of eMAC compared to Bispectral Index (BIS) for depth and nociceptive stimulation monitoring of anesthesia during general anesthesia.

Detailed Description
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eMAC is a new index based on response surface model for evaluating anesthesia state and anti-nociceptive stimulation levels. To valid it's clinical accuracy, a protocol was designed. Patients will be allocated to receive a specific effect-site concentration of remifentanil and propofol during tonic electrical stimulation (5s, 50mA) and intubation. The concentration combinations include the electrical stimulation combination (effector chamber concentration random: remifentanil 0-3 ng/ml, propofol 3-5 ug/ml) and the intubation combination (effector chamber concentration random: remifentanil 3-5 ng/ml, propofol 3-5 ug/ml). All combinations were decided before operation. Every combination had a 5 min equilibration period, and the vital signs (Heart Rate, Blood pressure, any body movement) and BIS, eMAC will be recorded before and after the electrical stimulation and intubation. After this period, patients will be randomly allocated to receive an intravenous anesthesia or intravenous combined anesthesia, and regular anesthesia is executed. This study only records vital signs and BIS, eMAC during maintenance period of perioperative.

Official Title
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Detection of Nociceptive Stimulation and Anesthesia State by Equivalent Minimum Alveolar Concentration (eMAC) During Anesthesia With Varying Propofol and Remifentanil Concentrations

Conditions
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General Anaesthesia

Intervention / Treatment
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* Drug: Propofol
* Drug: Low Remifentanil
* Drug: Heigh Remifentanil
* Procedure: Intubation
* Procedure: tetanic electrical stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing elective surgery under general anesthesia; Patients with ASA rating I III; The age of the patient is more than 18 years old; The informed consent has been signed; Exclusion Criteria: Patients who are participating in other trials; Patients with cognitive impairment, mental illness or taking psychotropic drugs within three months; Patients with a history of stroke; Patients with a history of alcoholism (long-term drinking more than 5 years, daily white wine consumption ≥ 50ml); Pregnant women; Patients with BMI>30; Patients and family members who are unwilling to participate after understanding the research content; According to the evaluation of the researcher, the actual condition is not suitable for the patients participating in this trial.

Ages Eligible for Study
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Minimum Age: 18 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: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group 1 BIS under tetanic electrical stimulation<br>During tetanic electrical stimulation, and with propofol(random:3-5ug/ml) and remifentanil(random:0-3ng/ml), the response (body movement or hemodynamic change) was observed, and recorded it's BIS. | Drug: Propofol<br>* Propofol (Random:3-5ug/ml)<br>* Other names: Propofol for tetanic electrical stimulation and intubation;Drug: Low Remifentanil<br>* Remifentanil (Random:0-3ug/ml)<br>* Other names: Remifentanil for tetanic electrical stimulation;Procedure: tetanic electrical stimulation<br>* tetanic electrical stimulation before surgery<br>|
| Active Comparator: Group 2 eMAC under tetanic electrical stimulation<br>During tetanic electrical stimulation or intubation, and with propofol(random:3-5ug/ml) and remifentanil(random:0-3ng/ml), the response (body movement or hemodynamic change) was observed, and recorded it's eMAC. | Drug: Propofol<br>* Propofol (Random:3-5ug/ml)<br>* Other names: Propofol for tetanic electrical stimulation and intubation;Drug: Low Remifentanil<br>* Remifentanil (Random:0-3ug/ml)<br>* Other names: Remifentanil for tetanic electrical stimulation;Procedure: tetanic electrical stimulation<br>* tetanic electrical stimulation before surgery<br>|
| Active Comparator: Group 3 BIS under intubation<br>During intubation, and with propofol(random:3-5ug/ml) and remifentanil(random:3-5ng/ml), the response (body movement or hemodynamic change) was observed, and recorded it's BIS. | Drug: Propofol<br>* Propofol (Random:3-5ug/ml)<br>* Other names: Propofol for tetanic electrical stimulation and intubation;Drug: Heigh Remifentanil<br>* Remifentanil (Random:3-5ug/ml)<br>* Other names: Remifentanil for intubation;Procedure: Intubation<br>* Endotracheal intubation before surgery<br>|
| Active Comparator: Group 4 eMAC under intubation<br>During intubation, and with propofol(random:3-5ug/ml) and remifentanil(random:3-5ng/ml), the response (body movement or hemodynamic change) was observed, and recorded it's eMAC. | Drug: Propofol<br>* Propofol (Random:3-5ug/ml)<br>* Other names: Propofol for tetanic electrical stimulation and intubation;Drug: Heigh Remifentanil<br>* Remifentanil (Random:3-5ug/ml)<br>* Other names: Remifentanil for intubation;Procedure: Intubation<br>* Endotracheal intubation before surgery<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prediction probability of eMAC | Prediction probability is an index(range:0-1) to describe the concordance between continuous measures and discrete scores. Prediction probability bettween eMAC and the lable of response was calculated. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prediction probability of BIS | Prediction probability is an index(range:0-1) to describe the concordance between continuous measures and discrete scores. Prediction probability bettween BIS and the lable of response was calculated. | 1 year |