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Anthropometric and US-Guided Difficult Intubation Prediction With ML Models

Evaluation of Anthropometric and Ultrasonographic Measurements With Different Machine Learning Methods in Predicting Difficult Intubation: A Prospective Observational Study

Status
Completed
Phases
Unknown
Study type
Observational
Source
ClinicalTrials.gov
Registry ID
NCT06904586
Enrollment
329
Registered
2025-04-01
Start date
2024-03-01
Completion date
2025-01-31
Last updated
2025-05-31

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

Conditions

Artificial Intelligence, Difficult Endotracheal Intubation

Brief summary

The assessment and management of difficult airway is of critical importance. Unsuccessful airway management leads to serious mortality and morbidity. From the beginning of the pre-anesthesia examination, 3% to 13% of patients who are considered suitable for routine airway management may be difficult to intubate. Airway assessment issues include risk assessment and airway examination (bedside and forward) to estimate the risk of difficult airway or aspiration. Airway examination aims to determine the presence of upper airway pathologies or anatomical anomalies. Some physical characteristics are associated with difficult airways and unsuccessful intubation. Examples of these are; limited neck movement, snoring, short sternomental distance, neck circumference thickness, etc. Physical characteristics can be measured with a meter or more detailed upper airway ultrasonographic measurements. In this study, researchers aimed to evaluate the anthropometric and ultrasonographic measurement values of patients who underwent preoperative airway assessment and to see the predictability of difficult intubation with artificial intelligence-supported decision support programs.

Detailed description

Difficult intubation, particularly unpredictable difficult intubation, is a challenging scenario for every anesthesiologist. Patients who are initially assessed as suitable for routine airway management may present as difficult to intubate in 5% to 22% of cases. Accurate evaluation and management of difficult airways are crucial, as failure in airway management can lead to serious morbidity and mortality. Airway assessment helps identify predictable difficult airways, but it does not exclude patients with normal clinical evaluations who may still experience unpredictable difficult intubation. The primary goal of airway examination is to detect upper airway pathologies or anatomical anomalies. Several physical characteristics are associated with difficult airways and failed intubation, including limited neck mobility, snoring, a short sternomental distance, and increased neck circumference. Common airway assessment tools, such as the Mallampati classification and the upper lip bite test, require patient cooperation, which limits their applicability in sedated, trauma, or unresponsive patients. The Cormack-Lehane classification, used during direct laryngoscopy, is invasive and does not allow for pre-procedural preparation. In this context, non-invasive, bedside, rapid, and accessible ultrasonographic assessments and anthropometric measurements have gained importance in predicting difficult airways. With technological advancements, decision-support systems and artificial intelligence (AI)-assisted applications are increasingly used to prevent adverse outcomes. Successful airway management is particularly critical in high-risk patients, where rapid decision-making is essential. Easily accessible, bedside, non-invasive ultrasonographic measurements, integrated with AI-based learning programs, have the potential to predict difficult intubation in advance. This enables early preparation, timely interventions, and the reduction of life-threatening risks. In this study, researchers aimed to predict difficult intubation preoperatively using non-invasive anthropometric and ultrasonographic upper airway measurements, combined with AI-assisted decision-support programs, without requiring any invasive procedures. Our hypothesis is that preoperative airway assessment through anthropometric and ultrasonographic measurements, supported by AI-based decision-support programs, can accurately predict difficult intubation and facilitate early preparation

Interventions

OTHERThyromental distance

Distance between the chin and thyroid cartilage with a tape measure when the patient is in a neutral position

OTHERNeck circumference

Measurement of neck circumference with a tape measure when the patient is in a neutral position

OTHERMouth opening distance

Distance between the upper and lower teeth at the point where the mouth opening is maximum when the patient is in a neutral position.

OTHERDistance from jawbone to hyoid bone with neck in neutral position

Distance from mentum to hyoid bone with neck in neutral position by ultrasonography

OTHERDistance from jawbone to hyoid bone with neck in extension

Ultrasound measurement of distance from mentum to hyoid bone with neck in extension

OTHERDistance between skin and trachea

Ultrasound measurement of distance between skin and trachea

OTHERDistance between skin and epiglottis

Distance between skin and epiglottis measured by ultrasonography

OTHERDistance between skin and anterior commissure of vocal cord:

Distance between skin and anterior commissure of vocal cord measured by ultrasonography

OTHERDistance between skin and hyoid bone

Distance between skin and hyoid bone measured by ultrasonography

OTHERMaximum Tongue Thickness

Measurement of Maximal Tongue Thickness by Ultrasonography

Sponsors

Duzce University
Lead SponsorOTHER

Study design

Observational model
COHORT
Time perspective
PROSPECTIVE

Eligibility

Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No

Inclusion criteria

* Patients over 18 years of age * Patients who will undergo general anesthesia

Exclusion criteria

* Pregnant women * Those with congenital and/or acquired facial deformities * Patients who have previously undergone upper neck airway surgery * Patients with head and neck tumors * Patients who will undergo thyroidectomy

Design outcomes

Primary

MeasureTime frameDescription
Support Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult IntubationsTaking ultrasonographic and anthropometric measurements of each patient took approximately 20 minutes. Machine learning estimates for each patient are approximately 1 min.The dataset, labeled based on expert assessment of difficult intubation, was classified using eight widely accepted machine learning algorithms: logistic regression (LR) \[6\], support vector machine (SVM) \[7\], random forest (RF) \[8\], K-nearest neighbors (KNN) \[9\], Gaussian naive Bayes (GNB) \[10\], CatBoost \[11\], XGBoost \[12\], and decision tree (DT) \[13\]. From the original 30 parameters, the 15 most influential features were selected based on feature extraction methods and literature relevance. Preprocessing steps included handling missing values, with incomplete records excluded. The dataset was split into training (80%) and test (20%) sets. Models were trained on the training set, with hyperparameter tuning performed via 5-fold cross-validation to avoid overfitting. Final model performance was evaluated on the independent test set.

Countries

Turkey (Türkiye)

Participant flow

Participants by arm

ArmCount
Patients Between the Ages of 18 and 20 Who Will Receive General Anesthesia
Thyromental distance: Distance between the chin and thyroid cartilage with a tape measure when the patient is in a neutral position Neck circumference: Measurement of neck circumference with a tape measure when the patient is in a neutral position Mouth opening distance: Distance between the upper and lower teeth at the point where the mouth opening is maximum when the patient is in a neutral position. Distance from jawbone to hyoid bone with neck in neutral position: Distance from mentum to hyoid bone with neck in neutral position by ultrasonography Distance from jawbone to hyoid bone with neck in extension: Ultrasound measurement of distance from mentum to hyoid bone with neck in extension Distance between skin and trachea: Ultrasound measurement of distance between skin and trachea Distance between skin and epiglottis: Distance between skin and epiglottis measured by ultrasonography Distance between skin and anterior commissure of vocal cord:: Distance between skin and anterior commissure of vocal cord measured by ultrasonography Distance between skin and hyoid bone: Distance between skin and hyoid bone measured by ultrasonography Maximum Tongue Thickness: Measurement of Maximal Tongue Thickness by Ultrasonography
329
Total329

Baseline characteristics

CharacteristicPatients Between the Ages of 18 and 20 Who Will Receive General Anesthesia
Age, Categorical
<=18 years
0 Participants
Age, Categorical
>=65 years
12 Participants
Age, Categorical
Between 18 and 65 years
317 Participants
Age, Continuous45 years
STANDARD_DEVIATION 20
Race and Ethnicity Not Collected— Participants
Region of Enrollment
Turkey
329 Participants
Sex: Female, Male
Female
190 Participants
Sex: Female, Male
Male
139 Participants

Adverse events

Event typeEG000
affected / at risk
deaths
Total, all-cause mortality
0 / 329
other
Total, other adverse events
0 / 329
serious
Total, serious adverse events
0 / 329

Outcome results

Primary

Support Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult Intubations

The dataset, labeled based on expert assessment of difficult intubation, was classified using eight widely accepted machine learning algorithms: logistic regression (LR) \[6\], support vector machine (SVM) \[7\], random forest (RF) \[8\], K-nearest neighbors (KNN) \[9\], Gaussian naive Bayes (GNB) \[10\], CatBoost \[11\], XGBoost \[12\], and decision tree (DT) \[13\]. From the original 30 parameters, the 15 most influential features were selected based on feature extraction methods and literature relevance. Preprocessing steps included handling missing values, with incomplete records excluded. The dataset was split into training (80%) and test (20%) sets. Models were trained on the training set, with hyperparameter tuning performed via 5-fold cross-validation to avoid overfitting. Final model performance was evaluated on the independent test set.

Time frame: Taking ultrasonographic and anthropometric measurements of each patient took approximately 20 minutes. Machine learning estimates for each patient are approximately 1 min.

ArmMeasureGroupValue (NUMBER)
Patients Between the Ages of 18 and 20 Who Will Receive General AnesthesiaSupport Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult Intubationssupport vector macine Accuracy89.39 percentage of estimate
Patients Between the Ages of 18 and 20 Who Will Receive General AnesthesiaSupport Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult IntubationsLogistic Regression Accuracy77.27 percentage of estimate
Patients Between the Ages of 18 and 20 Who Will Receive General AnesthesiaSupport Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult IntubationsRandom Forest Accuracy87.88 percentage of estimate
Patients Between the Ages of 18 and 20 Who Will Receive General AnesthesiaSupport Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult IntubationsDecision Tree Accuracy80.30 percentage of estimate
Patients Between the Ages of 18 and 20 Who Will Receive General AnesthesiaSupport Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult IntubationsK-Nearest Neighbors Accuracy74.24 percentage of estimate
Patients Between the Ages of 18 and 20 Who Will Receive General AnesthesiaSupport Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult IntubationsGaussian Naive Bayes Accuracy71.21 percentage of estimate
Patients Between the Ages of 18 and 20 Who Will Receive General AnesthesiaSupport Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult IntubationsCatBoost Accuracy83.33 percentage of estimate
Patients Between the Ages of 18 and 20 Who Will Receive General AnesthesiaSupport Vector Machine Algorithm Percentage of Accuracy in Predicted Difficult IntubationsXGBoost Accuracy81.82 percentage of estimate

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