Correlation Between Bedside Anatomical Indicators and Lifting Force and Glottic Exposure Under Different Video Laryngoscopy Techniques
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
Conditions
Intervention / Treatment
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
Enrollment (Estimated)
Contacts and Locations
Study Contact
- Name: Jin
- Phone Number: +86-18235572836
- Email: 1806442507@qq.com
Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Sampling Method
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
How is the study designed?
Design Details
- Observational Models: COHORT
- Time Perspectives: PROSPECTIVE
Cohorts and Interventions
Group / Cohort |
Intervention / Treatment |
|---|---|
|
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. |
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
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
Outcome Measure |
Time Frame |
|---|---|
|
Delta POGO (ΔPOGO)
Time Frame: Perioperative
|
Perioperative
|
|
Incidence of Difficult Glottic Exposure
Time Frame: Perioperative
|
Perioperative
|
Collaborators and Investigators
Study record dates
Study Major Dates
Study Start (Estimated)
Primary Completion (Estimated)
Study Completion (Estimated)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Other Study ID Numbers
- [2026]YX172
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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