This study is designed as a prospective observational study and will be conducted at the Health Sciences University Antalya Training and Research Hospital. Adult patients scheduled to undergo bariatric surgery will be included.
The aim of this study is to compare the El Ganzouri Risk Index (EGRI) and airway ultrasonography (USG) parameters in predicting difficult intubation and to evaluate their relationship with the Cormack-Lehane (CL) score obtained during direct laryngoscopy.
Before surgery, each participant will be evaluated using both the EGRI scoring system and airway USG. During general anesthesia, tracheal intubation will be performed using direct laryngoscopy, and data including the CL score, intubation time, number of attempts, and the need for videolaryngoscopy will be recorded based on the anesthesiologist's observations.
The collected data will be analyzed by classifying participants according to the presence or absence of difficult intubation, and statistical comparisons will be performed between EGRI scores and airway ultrasonography parameters. The results of this study may contribute to improved preoperative airway assessment and enhanced patient safety in bariatric surgery.
Adult patients aged 18 to 65 years.
ASA physical status classification II or III.
Scheduled to undergo elective bariatric surgery under general anesthesia.
Patients who voluntarily agree to participate in the study and sign the informed consent form.
Patients younger than 18 years or older than 65 years
Presence of upper airway anatomical pathology
History of tracheal or thyroid surgery.
History of radiotherapy to the head and neck region.
The study population will consist of adult participants aged 18 to 65 years with ASA physical status II or III who are scheduled to undergo elective bariatric surgery under general anesthesia. Eligible participants must provide written informed consent prior to inclusion in the study. Participants with upper airway anatomical pathology, previous tracheal or thyroid surgery, head or neck masses, history of radiotherapy to the head and neck region, cervical spine anomalies, or those unwilling to participate will be excluded.
Cohort
Prospective
Not listed
Association between each individual ultrasound parameter and difficult laryngoscopy
Difficult laryngoscopy will be defined as CL grades III-IV, which will serve as the reference standard. Each predefined airway ultrasonography parameter will be analyzed independently to evaluate its association with difficult laryngoscopy. No composite score will be calculated. The following preoperative airway ultrasonography measurements will be assessed individually: Tongue base thickness Hyomental distance in the neutral position Hyomental distance in the extended position Hyomental ratio (extension/neutral) Skin-to-hyoid distance Skin-to-epiglottis distance Skin-to-vocal cords (anterior commissure) distance Skin-to-cricoid cartilage distance Pre-epiglottic space depth Unit of Measure Centimeters (cm) for all linear measurements
Comparison of Diagnostic Performance Between the EGRI and Airway USG Measurements
The diagnostic performance of the El Ganzouri Risk Index (EGRI) and individual airway ultrasonography measurements will be compared for the prediction of difficult laryngoscopy. The EGRI is a seven-item multivariable bedside airway assessment index with a total score ranging from 0 to 12, where higher scores indicate an increased risk of difficult intubation. Each item is scored using predefined cut-off values and summed to generate a single composite EGRI score. The EGRI components include: Mouth opening Thyromental distance Mallampati classification Neck extension Mandibular protrusion Body weight History of difficult intubation Airway USG parameters will be analyzed independently, as defined in the primary outcome measure. Difficult laryngoscopy will be defined as CL grades III-IV, which will serve as the reference standard. Unit of Measure Score (0-12) for the El Ganzouri Risk Index Centimeters (cm) for airway ultrasonography measurements
Association Between Airway Ultrasonography Parameters and Intubation Performance
Associations between individual preoperative airway ultrasonography measurements and intubation performance metrics will be evaluated. Each airway ultrasonography parameter will be analyzed independently. Intubation performance metrics include: Intubation time Number of intubation attempts Requirement for videolaryngoscopy Occurrence of intubation-related complications Unit of Measure Seconds for intubation time Count for number of intubation attempts Binary (yes/no) for videolaryngoscopy requirement Binary (yes/no) for intubation-related complications
Predictive Performance of the EGRI for Difficult Laryngoscopy
The predictive performance of EGRI total score will be evaluated for the identification of difficult laryngoscopy. Difficult laryngoscopy will be defined as CL grades III-IV, which will serve as the reference standard. The EGRI is a composite bedside airway assessment index with a total score ranging from 0 to 12, where higher scores indicate an increased risk of difficult intubation.
Association Between Early Intraoperative Hemodynamic Instability and Difficult Laryngoscopy
The association between early intraoperative hemodynamic instability and difficult laryngoscopy will be evaluated. Difficult laryngoscopy will be defined as CL grades III-IV, which will serve as the reference standard. Hemodynamic parameters will be recorded at 5-minute intervals during the first 30 minutes of surgery, including heart rate, arterial blood pressure, and peripheral oxygen saturation. The following pre-specified derived variables will be used for analysis: Lowest mean arterial pressure (MAP) within the first 30 minutes Lowest peripheral oxygen saturation (SpO₂) within the first 30 minutes Duration of hypotension, defined as the number of 5-minute intervals with MAP \< 65 mmHg Duration of hypoxemia, defined as the number of 5-minute intervals with SpO₂ \< 90% Maximum decrease in MAP from the pre-induction baseline (ΔMAP) Each derived variable will be analyzed as an indicator of hemodynamic instability.
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