Correlation Between Bedside Anatomical Indicators and Lifting Force and Glottic Exposure Under Different Video Laryngoscopy Techniques

September 22, 2026 updated by: Zheng Guo, Second Hospital of Shanxi Medical University

This single-center prospective observational study plans to enroll 196 patients undergoing elective general anesthesia. The study aims to investigate the correlation between preoperative bedside anatomical indicators (including modified Mallampati classification, upper lip bite test, mouth opening, head circumference, and thyromental distance) and the peak lifting force applied during video laryngoscopy, as well as the degree of glottic exposure (POGO score). The study will also evaluate the potential benefit of the direct epiglottis elevation technique in specific anatomical subgroups. After anesthesia induction, the same anesthesiologist will perform video laryngoscopy using two distinct techniques in a fixed sequence: the indirect (vallecula) method and the direct (subepiglottic) method. Peak lifting force will be quantitatively measured in real-time using a resistive thin-film pressure sensor attached to the laryngoscope blade. The primary outcomes are the POGO scores and peak lifting forces under both techniques. The secondary outcome includes the change in POGO score (ΔPOGO) between techniques. The study will provide quantitative evidence regarding the "anatomy-force-view" relationship and aid in individualized clinical decision-making for video laryngoscopy intubation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This study is a single-center, prospective, observational study. A total of 196 adult patients scheduled for elective surgery under general anesthesia requiring orotracheal intubation will be enrolled. Preoperative bedside anatomical assessment will be performed by a standardized, blinded evaluator. The assessed indicators include mouth opening, thyromental distance, modified Mallampati classification, upper lip bite test, head circumference, and neck circumference. After standard anesthesia induction, video laryngoscopy will be performed by an experienced anesthesiologist. Two techniques will be evaluated in a fixed sequence: (1) Indirect epiglottis elevation (vallecula method): the blade tip is placed in the vallecula to indirectly elevate the epiglottis by lifting the tongue base. (2) Direct epiglottis elevation (subepiglottic method): the blade tip is advanced past the vallecula and placed directly under the laryngeal surface of the epiglottis to actively lift it. A resistive thin-film pressure sensor attached to the video laryngoscope blade will continuously record real-time force data, and the peak lifting force will be extracted for analysis. Glottic exposure will be evaluated using the Percentage of Glottic Opening (POGO) score. Between the two assessments, mask ventilation will be performed for at least 2 minutes to maintain SpO2 ≥ 98%. All procedures and data collection will adhere to the approved protocol by the Ethics Committee of the Second Hospital of Shanxi Medical University (Approval No. [2026] YX No. 172). Statistical analyses will be performed using SPSS 26.0 and R software, including Spearman rank correlation, Kruskal-Wallis test, and multiple linear regression with Bootstrap validation.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
200

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Adult patients aged 18 to 75 years with ASA physical status I to III who are scheduled for elective surgery under general anesthesia requiring orotracheal intubation under video laryngoscopy guidance. Patients with known difficult airway, facial or neck abnormalities affecting landmark palpation, limited mouth opening (< 2.0 cm), or edentulism are excluded.

Description

Inclusion Criteria:

  • - Age 18 to 75 years
  • ASA physical status I to III
  • Scheduled for orotracheal intubation under video laryngoscopy guidance
  • Written informed consent obtained

Exclusion Criteria:

  • Known history of difficult airway or anticipated need for awake intubation

    • Facial or neck trauma, burns, or surgical history affecting palpation of anatomical landmarks
    • Temporomandibular joint ankylosis or mouth opening < 2.0 cm
    • Edentulous patients

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

  • Observational Models: COHORT
  • Time Perspectives: PROSPECTIVE

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Patients Undergoing Video Laryngoscopy

Adult patients scheduled for elective general anesthesia requiring orotracheal intubation under video laryngoscopy guidance. All participants will undergo both indirect and direct epiglottis elevation techniques in a fixed sequence.
Procedure: Direct Epiglottis Elevation (Subepiglottic Method)

Video laryngoscopy blade tip advanced past the vallecula and placed under the laryngeal surface of the epiglottis to directly lift it.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Peak Lifting Force with Direct Epiglottis Elevation
Time Frame: Perioperative

Peak lifting force (gf) measured by a resistive thin-film pressure sensor attached to the video laryngoscope blade during the direct (subepiglottic) technique.
Perioperative
Peak Lifting Force with Indirect Epiglottis Elevation
Time Frame: Perioperative

Peak lifting force (gf) measured by a resistive thin-film pressure sensor attached to the video laryngoscope blade during the indirect (vallecula) technique.
Perioperative
POGO Score with Indirect Epiglottis Elevation
Time Frame: Perioperative

Percentage of Glottic Opening (POGO) score assessed via video laryngoscopy using the indirect (vallecula) technique. The scale ranges from 0% to 100%, where higher scores indicate better visualization of the glottis (better outcome).
Perioperative
POGO Score with Direct Epiglottis Elevation
Time Frame: Perioperative

Percentage of Glottic Opening (POGO) score assessed via video laryngoscopy using the direct (subepiglottic) technique. The scale ranges from 0% to 100%, where higher scores indicate better visualization of the glottis (better outcome).
Perioperative

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Delta POGO (ΔPOGO)
Time Frame: Perioperative
Perioperative
Incidence of Difficult Glottic Exposure
Time Frame: Perioperative
Perioperative

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Second Hospital of Shanxi Medical University

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 (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 16, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 22, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 29, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 22, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • [2026]YX172

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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