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Combined Ultrasonographic Skin-to-Epiglottis Distance With Modified Mallampati Versus Modified Mallampati Score Alone in Predicting Difficult Laryngoscopy During Tracheal Intubation Under General Anesthesia

Combined Ultrasonographic Skin-to-Epiglottis Distance With Modified Mallampati Versus Modified Mallampati Score Alone in Predicting Difficult Laryngoscopy During Tracheal Intubation Under General Anesthesia: A Prospective, Randomized Double Blinded Controlled Study

Status
Not yet recruiting
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07315256
Enrollment
160
Registered
2026-01-02
Start date
2026-01-31
Completion date
2027-02-28
Last updated
2026-01-02

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Mallampati Score, Mallampati Score, Difficult Intubation, Videolaryngoscope, Tracheal Intubation, Ultrasonographic

Keywords

Difficult Laryngoscopy, Tracheal Intubation, Modified Mallampati

Brief summary

This study will evaluate how well an ultrasound measurement of the distance from the skin to the epiglottis, when combined with the modified Mallampati score, can predict difficult laryngoscopy in adult patients undergoing elective surgery under general anesthesia. Adult patients scheduled for surgery requiring tracheal intubation will be randomly assigned to two assessment strategies before anesthesia: one group will have the usual bedside airway assessment with modified Mallampati alone, and the other group will have modified Mallampati plus a quick, painless ultrasound scan of the front of the neck to measure the skin-to-epiglottis distance. During intubation, the anesthesiologist, who is blinded to the preoperative assessments, will grade the laryngoscopic view using the Cormack-Lehane classification, and the investigators will compare how accurately each assessment approach predicts difficult laryngoscopy (grade 3-4). The study does not change how anesthesia or airway management is performed; ultrasound and clinical assessments are added solely for measurement and data collection, with minimal risk to participants and potential future benefits in improving airway risk stratification and patient safety.

Detailed description

This is a prospective, randomized, double-blinded controlled study designed to evaluate whether combining preoperative ultrasonographic skin-to-epiglottis distance (SED) with the modified Mallampati score improves prediction of difficult laryngoscopy compared with the modified Mallampati score alone in adult elective surgical patients undergoing tracheal intubation under general anesthesia. Eligible patients will be randomly assigned to one of two groups: Group A will undergo standard preoperative airway assessment including modified Mallampati score only, while Group B will receive both modified Mallampati assessment and ultrasound measurement of SED using a standardized anterior neck scanning protocol in the preoperative area. All patients will subsequently undergo direct laryngoscopy for tracheal intubation in the operating room, performed by an experienced anesthesiologist who is blinded to the preoperative airway assessment results; the Cormack-Lehane laryngoscopic view during the first intubation attempt will be recorded as the reference standard for defining difficult laryngoscopy (grade 3-4). Additional data collected will include age, sex, body mass index, relevant comorbidities, and type of surgery to allow adjustment for potential confounders. The primary endpoint is the diagnostic accuracy (area under the receiver operating characteristic curve) of SED plus modified Mallampati versus modified Mallampati alone for predicting difficult laryngoscopy. Secondary endpoints include the correlation of SED with Cormack-Lehane grade, sensitivity, specificity, and predictive values of each assessment strategy, and exploratory subgroup analyses in higher-risk patients such as those with obesity.

Interventions

DIAGNOSTIC_TESTUltrasound-Guided Skin-to-Epiglottis Distance Measurement

Point-of-care airway ultrasound of the anterior neck using a high-frequency linear probe (10-13 MHz) placed transversely at the thyrohyoid membrane to measure the vertical skin-to-epiglottis distance in millimeters. The scan is performed preoperatively in supine neutral position, is non-invasive and painless, and does not alter anesthetic or airway management, which follow standard clinical practice. This measurement is combined with the modified Mallampati score in the experimental arm to predict difficult laryngoscopy (Cormack-Lehane grade 3-4).

DIAGNOSTIC_TESTClinical Airway Assessment With Modified Mallampati Score

Standard preoperative bedside airway assessment using the modified Mallampati score without airway ultrasound; performed in the sitting position with mouth opening and maximal tongue protrusion, used routinely to anticipate difficulty of laryngoscopy.

Sponsors

Assiut University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
DIAGNOSTIC
Masking
DOUBLE (Subject, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No

Inclusion criteria

* Adults aged 18-65 years. * ASA physical status I-II. * Scheduled for elective surgery under general anesthesia requiring tracheal intubation with direct laryngoscopy. * Able to provide written informed consent.

Exclusion criteria

* Emergency surgery. * Known or suspected difficult airway requiring planned alternative intubation technique (e.g., awake fiberoptic). * History of significant upper airway pathology, neck mass, prior neck surgery, or radiation affecting airway anatomy. * Limited mouth opening, cervical spine instability, or contraindication to standard sniffing position. * Pregnancy. * Refusal or inability to provide informed consent.

Design outcomes

Primary

MeasureTime frameDescription
Diagnostic accuracy of Ultrasonographic Skin-to-Epiglottis Distance plus Mallampati vs Mallampati alone for difficult laryngoscopyFrom induction of anesthesia to completion of first direct laryngoscopy (intraoperative, approximately 10 minutes).Area under the receiver operating characteristic (ROC) curve (AUC) of the combined ultrasound skin-to-epiglottis distance plus modified Mallampati score compared with the AUC of the modified Mallampati score alone for predicting difficult laryngoscopy, defined as Cormack-Lehane grade 3-4 on first direct laryngoscopy attempt.

Secondary

MeasureTime frameDescription
Correlation between skin-to-epiglottis distance and Cormack-Lehane gradeFrom preoperative ultrasound assessment to completion of first direct laryngoscopy (same operative session, approximately 30 minutes).Pearson or Spearman correlation coefficient between the ultrasound-measured midline skin-to-epiglottis distance and the Cormack-Lehane laryngoscopic grade recorded on the first intubation attempt in all patients who undergo airway ultrasound.

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026