Effect of Brain GABA Metabolite Amount to Propofol Utilisation Under TIVA in Hypothyroid Patient (BrainGABA)

March 18, 2025 updated by: Duzce University

Introduction: GABAergic synaptic transmigration in the anterior cingulate (ACC) cortex of hypothyroid rats has been demonstrated by electrophysiologic recordings. In this study, the investigators primary aim was to determine whether the dose requirement of propofol used under the guidance of bispectral index monitoring is correlated with thyroid hormone levels in patients undergoing surgery under total intravenous anaesthesia.The investigators secondary aim was to determine whether there is a difference in the amount of GABA metabolite in the midline posterior (mPCC) and midline anterior cingulate cortex (mACC) region in normal and thyroid dysfunction patients on magnetic resonance spectroscopic imaging.

Method: After ethics committee approval, the study included patients with ASA I-II status: Group 1 (Control group n=40) patients with regular thyroid function tests and Group 2 (Hypothyroid group n=40) patients with hypothyroidism history with Levothyroxine sodium treated. Patients were evaluated preoperatively with the Montreal assessment scale and Beck anxiety scale. Written informed consent was obtained from all the patients, andparticipants underwent a brain MRI examination one day before the operation. The possible increase of GABA, which is present in the imaging with NAA, Cr and Glx in the range of 2.2-2.4 ppm, was recorded as an elevated spectral curve in the MR spectroscopy spectrum and its numerical equivalent was determined as the amount of chemical shifting in the y-axis. To determine GABA, the investigators set the sequence with optimal parameters, for which the investigators set the radio frequency pulse-echo time (TE) as 20 msec.The investigators set the voxel size as 2*3*3 cm to obtain optimal results. Researchers determined single voxel imaging MR spectroscopy sampling area in the midline anterior and posterior to the cingulate gyrus in all patients. Patients with spectral voxels outside the specified area, dense ventricular contamination within the voxel, or with intra-voxel dense ventricular contamination or seminal contamination were excluded from the study.

Patients were operated on under total intravenous anaesthesia. Anesthesia Induction was performed with 2 mg/kg propofol, 0.5 mg/kg fentanyl and 0.5 mg/kg rocuronium. Maintenance was achieved by bispectral index monitoring with propofol infusion at a dose of 1-8 mg/kg/min and remifentanil infusion at a dose of 0.5-2 mcg/kg/min with values between 40-60.

Study Overview

Status

Completed

Conditions

Detailed Description

It is generally accepted that thyroid hormones have important effects on the normal functioning of the adult brain. Hypothyroidism is a common endocrine disorder characterized by low secretion of thyroid hormone. It is often associated with cognitive and neuropsychiatric changes. Multimodal imaging studies have demonstrated structural and functional changes in the brain in patients with hypothyroidism. Publications have reported decreased hippocampal area, microstructural changes in brain white matter, changes in brain metabolic rate, decreased regional blood flow, decreased cerebral glucose metabolism, decreased functional connectivity and decreased cortical excitability.

It is noteworthy that the hormone affects GABAergic neurotransmission. Preclinical studies have shown that T3 and T4 hormones modulate GABA receptor activity. Recent studies in rat hippocampus have shown a decrease in GABA levels in the hippocampus in the hypothyroid group. Anesthetic drugs that researchers use as daily routine anesthetic applications in the clinic for general anesthesia mostly show their effects through GABA receptors. Therefore, the investigators argue that in thyroid hormone disorders, which are effective on the GABAergic system, the need for anesthetic substances routinely used during general anesthesia may vary compared to patients with normal thyroid function.

The investigators study, they aimed to observe whether there is a difference between the anesthetic substance requirements of patients with normal thyroid function and hypothyroid patients under general anesthesia with monitoring. The researchers also aimed to observe whether there is a regional difference in non-contrast MR spectroscopic evaluation in patients with normal and low thyroid dysfunction. There were no invasive procedures in the investigators study.

Study Type

Observational

Enrollment (Actual)

80

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey
    • DU
      • Duzce, DU, Turkey, 81620
        • Duzce University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Patients ASAI-II status, older than 18 years and younger than 65 years who will be operated under total intravenous anesthesia

Description

Inclusion Criteria:

  • Patients older than 18 years and younger than 65 years who will be operated under total intravenous anesthesia
  • ASAI-II status

Exclusion Criteria:

  • Patients for whom Intensive Care Unit (ICU) indication is foreseen
  • Chronic obstructive pulmonary disease,
  • A personal or family history of malignant hyperthermia,
  • Alcohol or drug addiction,
  • History of liver or kidney disease,
  • With coronary artery disease or heart failure,
  • Significant anemia or hemoglobinopathy,
  • Hypotension, hypovolemia, sepsis,
  • Unregulated diabetic patients,
  • Female patients who are pregnant or lactating.
  • Allergic to propofol and halogens
  • Patients on gabapentinoids
  • Those with a history of head trauma
  • Those with neurological disorders

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Group 1
Control group (n=40) Patients with normal thyroid function tests
Group 2
Hypothyroid patients group (n=40) . Hypothyroid and treated with Levothyroxine

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes of participants' thyroid hormone levels measured before anesthesia and doses of propofol and remifentanil used in total intravenous anesthesia under bispectral index monitoring.
Time Frame: From enrollment to the end of treatment at 1 day
The difference of participants' thyroid hormone levels (IU/mL) before anesthesia and compare the doses of propofol in miligram and remifentanil in microgram used in total intravenous anesthesia under bispectral index monitoring.
From enrollment to the end of treatment at 1 day

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in the amounts of brain GABA metabolites chemical shifts measured in ppm units between participants with hypothyroidism and participants with normal thyroid function before anesthesia. .
Time Frame: From enrollment to the end of treatment at 1 day
To determine whether there is a difference in the amount of GABA metabolite in the midline posterior (mPCC) and midline anterior cingulate cortex (mACC) region in normal and thyroid dysfunction patients on magnetic resonance spectroscopic imaging and its correlation of the propofol and remifentanil needing.
From enrollment to the end of treatment at 1 day

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Duzce University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 23, 2023

Primary Completion (Actual)

August 1, 2024

Study Completion (Actual)

October 1, 2024

Study Registration Dates

First Submitted

October 17, 2024

First Submitted That Met QC Criteria

October 17, 2024

First Posted (Actual)

October 18, 2024

Study Record Updates

Last Update Posted (Actual)

March 25, 2025

Last Update Submitted That Met QC Criteria

March 18, 2025

Last Verified

March 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2023-117

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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