Equivalent MAC in General Anesthesia

NCT07197567 | Completed

• 1 other identifier: SEAH-EMAC-2025
• Study Type: observational
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

This observational study aims to evaluate the clinical applicability of the Equivalent Minimum Alveolar Concentration (eMAC) parameter during general anesthesia. eMAC is a recently developed index that combines the effects of both inhalational and intravenous anesthetics, providing a unified measure of anesthetic depth. While the traditional Minimum Alveolar Concentration (MAC) is widely used for inhalational agents, it does not reflect intravenous anesthetics or combined techniques such as Combined Intravenous and Inhalational Anesthesia (CIVIA). In this study, adult patients undergoing elective surgery under general anesthesia will be observed. Standard clinical practice will not be altered. Demographic and clinical parameters, including eMAC, MAC, Bispectral Index (BIS), and hemodynamic variables, will be recorded at defined perioperative time points. No experimental drugs or additional procedures will be administered. The primary aim is to investigate the correlation between eMAC and MAC values obtained during anesthesia. Secondary objectives include assessing the relationship between eMAC and BIS values, comparing eMAC, MAC, and BIS across different anesthetic techniques, and evaluating hemodynamic stability in relation to anesthetic depth. The results of this study may contribute to a better understanding of eMAC and its potential role in clinical anesthesia practice.

Conditions

General Anesthesia; Anesthetic Depth; Intraoperative Monitoring

Keywords

Equivalent Minimum Alveolar Concentration; eMAC; Minimum Alveolar Concentration; MAC; Bispectral Index; BIS; Anesthesia Depth; Combined Intravenous and Inhalational Anesthesia; CIVIA; Propofol; Sevoflurane

Outcome Measures

Primary Outcomes (1)

• Correlation between Equivalent Minimum Alveolar Concentration (eMAC) and Minimum Alveolar Concentration (MAC)

  To determine the relationship between eMAC values and conventional MAC values obtained from the anesthesia workstation.

  From induction of anesthesia until the end of surgery (measured at five perioperative time points: prior to induction, 5 minutes after induction, at surgical incision, at the midpoint of surgery, and at the end of surgery)

Secondary Outcomes (5)

• Correlation between eMAC and Bispectral Index (BIS)

  From induction of anesthesia until the end of surgery (measured at five perioperative time points: prior to induction, 5 minutes after induction, at surgical incision, at the midpoint of surgery, and at the end of surgery)

• Comparison of eMAC, MAC, and Bispectral Index (BIS) Values Measured by Anesthesia Workstation and BIS Monitor Across Different Anesthetic Techniques

  From induction of anesthesia until the end of surgery (measured at five perioperative time points: prior to induction, 5 minutes after induction, at surgical incision, at the midpoint of surgery, and at the end of surgery)

• Heart Rate During Anesthesia

  From induction of anesthesia until the end of surgery (measured at five perioperative time points: prior to induction, 5 minutes after induction, at surgical incision, at the midpoint of surgery, and at the end of surgery)

• Mean Arterial Pressure During Anesthesia

  From induction of anesthesia until the end of surgery (measured at five perioperative time points: prior to induction, 5 minutes after induction, at surgical incision, at the midpoint of surgery, and at the end of surgery)

• Peripheral Oxygen Saturation (SpO₂) During Anesthesia

  From induction of anesthesia until the end of surgery (measured at five perioperative time points: prior to induction, 5 minutes after induction, at surgical incision, at the midpoint of surgery, and at the end of surgery)

Study Arms (2)

Inhalational Anesthesia Group

Patients receiving general anesthesia maintained with inhalational agents (e.g., sevoflurane) according to standard clinical practice.

Drug: Sevoflurane + Remifentanil

Combined Intravenous-Inhalational Anesthesia (CIVIA) Group

Patients receiving general anesthesia with a combination of intravenous and inhalational agents according to standard clinical practice.

Drug: Sevoflurane + Propofol + Remifentanil

Interventions

Sevoflurane + Remifentanil DRUG

Combination of an inhalational anesthetic (sevoflurane) and an intravenous opioid analgesic (remifentanil), both routinely used in clinical practice for maintenance of general anesthesia. These agents are administered according to standard of care, not as experimental interventions.

Inhalational Anesthesia Group

Sevoflurane + Propofol + Remifentanil DRUG

Combination of an inhalational anesthetic (sevoflurane), an intravenous anesthetic (propofol), and an intravenous opioid analgesic (remifentanil). These agents are routinely used together in clinical practice for combined intravenous-inhalational anesthesia (CIVIA). All drugs are administered according to standard of care, not as experimental interventions.

Combined Intravenous-Inhalational Anesthesia (CIVIA) Group

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adult patients scheduled for elective surgical procedures under general anesthesia at Sakarya University Training and Research Hospital, Department of Anesthesiology and Reanimation, will be considered for enrollment. Patients represent a typical surgical population with ASA physical status I-III.

You may qualify if:

• Adults aged 18-65 years
• Scheduled for elective surgery under general anesthesia
• American Society of Anesthesiologists (ASA) Physical Status I-III
• Feasibility of Bispectral Index (BIS) monitoring
• Provision of written informed consent

You may not qualify if:

• History of neurological disease (e.g., epilepsy, dementia, severe brain injury)
• Known allergy to anesthetic agents
• Severe cardiovascular or respiratory failure

Sponsors & Collaborators

• Sakarya University: lead

Study Sites (1)

Sakarya University Training and Research Hospital, Department of Anesthesiology and Reanimation

Sakarya, Adapazari, Turkey (Türkiye)

Location

Related Publications (1)

• Zhang H, Zhang J, Li X, He S, Deng Z, Wang L, Wang Y, Wang X, Wan C, Huang F, Zhu Z, Dong H. Feasibility Study of an Indicator of Equivalent Potency of Multiple Anesthetics Normalized by Minimum Alveolar Concentration Derived From Response Surface Models. Anesth Analg. 2026 Mar 1;142(3):541-550. doi: 10.1213/ANE.0000000000007514. Epub 2025 Apr 17.

  PMID: 40244902 BACKGROUND

MeSH Terms

Interventions

Sevoflurane; Remifentanil; Propofol

Intervention Hierarchy (Ancestors)

Methyl Ethers; Ethers; Organic Chemicals; Hydrocarbons, Fluorinated; Hydrocarbons, Halogenated; Hydrocarbons; Propionates; Acids, Acyclic; Carboxylic Acids; Piperidines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic

Study Officials

• Ayca Tas Tuna, Professor, M.D.

  Sakarya University Faculty of Medicine

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof.Dr.

Study Record Dates

• First Submitted: August 31, 2025
• First Posted: September 29, 2025
• Study Start: November 1, 2025
• Primary Completion: January 15, 2026
• Study Completion: January 15, 2026
• Last Updated: March 10, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)