An interventional study of Ultrasound and Cole's Formula in Endotracheal Tube Wrongly Placed During Anesthetic Procedure, sponsored by Ain Shams University. Recruiting at 1 site in Egypt. Open to participants aged 3 Months to 8 Years. Per ClinicalTrials.gov, last updated 2026-05-14.
Sponsored by Ain Shams University · Not applicable, Interventional, and Other
To compare the accuracy of ultrasound-guided subglottic diameter measurement versus age-based formulas in determining the optimal endotracheal tube (ETT) size in pediatric patients with single ventricle physiology and reducing post-extubation complications.
To compare the accuracy of ultrasound-guided subglottic diameter measurement versus age-based formulas in determining optimal ETT size in pediatric patients with single ventricle physiology to avoid post-extubation complications. All legal guardians will provide written informed consent after a full explanation of the study. During the pre-anesthetic evaluation, demographic data, ASA physical status, relevant comorbidities, and a recent echocardiogram confirming single ventricle physiology will be documented. In the operating room, patients will be monitored using standard ASA monitors including ECG, non-invasive blood pressure, pulse oximetry, and capnography, followed by preoxygenation with 100% oxygen. If intravenous access is available, anesthesia will be induced with ketamine, fentanyl, and rocuronium. If IV access is not available, inhalational induction with sevoflurane will be used until IV access is secured, after which fentanyl and rocuronium will be administered. Following induction, ventilation will continue with FiO₂ 100% and sevoflurane 1.5% for 3 minutes.
Patients will be divided into two groups:
Group A (Age-Based Formula):
In neonates and infants under 1 year, a weight-based sizing is used:
In Infants > 1 year, ETT size will be selected based on the standard formula: Cole's Formula for uncuffed ETT.
ETT ID (mm) = (Age/4) + 4.
Group B (Ultrasound Group):
During mask ventilation, a trained anesthesiologist will perform transverse subglottic diameter measurement using a high-frequency linear ultrasound probe (7-15 MHz). The patient will be positioned supine with mild neck extension. The probe will be placed transversely just below the thyroid cartilage to identify the subglottic airway at the level of the cricoid cartilage. The measured diameter (in mm) will be recorded and used to determine ETT size from the equation:
ETT ID (mm) = Subglottic diameter (mm) × 0.8 To confirm appropriate ETT sizing, all patients will be placed on pressure-controlled mechanical ventilation and a leak test will be performed in both groups. Start with pressure 20-25 cm H₂O, if there is resistance to ETT passage into the trachea or no audible leak or ventilator-detected leak when the lungs are inflated, the tube will be exchanged for one that is 0.5 mm smaller. If a leak is detected, decrease the pressure to 10 cm H₂O. If there's still a detected leak at 10 cm H₂O, the ETT will be exchanged for one that is 0.5 mm larger. If there's no leak at 10 cm H₂O then the ETT is optimal. Tube size will be considered optimal when a tracheal leak is not detected at an inflation pressure between 10-20 cm H₂O with uncuffed tubes.
Ain Shams University is the lead sponsor of 1,876 studies on the registry; 423 are open to participants now.
Of its 32 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
In neonates and infants under 1 year, a weight-based sizing is used: * Infants \<1 kg (Preterm): 2.5 mm ETT * Infants 1-2 kg: 3 mm ETT * Infants 2-3 kg (Full Term): 3 - 3.5 mm ETT * Infants \>3 kg (3 months to 1 year): 3.5 - 4 mm ETT In Infants \> 1 year, ETT size will be selected based on the standard formula: Cole's Formula for uncuffed ETT. ETT ID (mm) = (Age/4) + 4.
Other: Cole's Formula
During mask ventilation, a trained anesthesiologist will perform transverse subglottic diameter measurement using a high-frequency linear ultrasound probe (7-15 MHz). The patient will be positioned supine with mild neck extension. The probe will be placed transversely just below the thyroid cartilage to identify the subglottic airway at the level of the cricoid cartilage. The measured diameter (in mm) will be recorded and used to determine ETT size from the equation: ETT ID (mm) = Subglottic diameter (mm) × 0.8
Device: Ultrasound
Using Ultrasound for accuracy of ETT sizing
Subglottic diameter in mm x 0.8
Accuracy of ETT size selection
Accuracy of endotracheal tube size selection measured by the number of ETT attempts required to achieve an appropriate leak test and successful airway placement.
Time frame: During endotracheal intubation, immediately after induction of anesthesia and neuromuscular blockade (within 10 minutes after induction)
Incidence of post-extubation stridor/croup
Occurrence of post-extubation stridor or croup assessed using the Westley croup score.
Time frame: From extubation until 24 hours post-extubation
Severity of post-extubation croup
Severity of post-extubation croup assessed using the Westley croup score
Time frame: At 30 minutes, 2 hours, and 24 hours after extubation
Duration of ICU stay related to airway complications
Length of ICU stay due to airway complications such as post-extubation stridor
Time frame: From ICU admission until ICU discharge, up to 30 days
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Ain Shams University