Real-time Sonography in Detecting Inadvertent Esophageal Intubation Among Difficult Intubation Patients

Real-time Sonography as an Auxiliary Approach to Detect Inadvertent Esophageal Intubation Before Ventilation Among Suspected Difficult Intubation Patients: a Randomized Control Study

Early detection of esophageal intubation, one of the most common complications while performing endotracheal intubation (ETI), is crucial to adequate airway management, especially among patients suspected of difficult intubation (DI). Detective approaches with ventilation require time, increase the risk of emesis and aspiration to patients, and increase the risk of particle aerosolization to health providers under the epidemic of aerosol-borne diseases. Our study will determine the effectiveness of real-time sonography assisted to direct visualization to detect esophageal intubation before ventilation among DI patients.

A single-blind, superiority, randomized controlled study. 224 eligible participants requiring elective orotracheal intubation under general anesthesia with suspected DI will be randomized 1:1 to sonography and direct visualization versus direct visualization alone. The primary objective will be to investigate, in suspected DI patients, if the real-time sonography-assisted with direct visualization results in improved specificity in the detection of inadvertent esophageal intubation before ventilation compared with direct visualization while performing intubation. The secondary objectives will be to compare the sensitivity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), diagnostic odds ratio (DOR), positive predictive value (PPV), negative predictive value (NPV), and detective self-confidence grade using sonography-assisted direct visualization vs direct visualization. Test characteristics will be calculated using standard formulas for a binomial proportion, and the corresponding 95% confidence intervals (CIs), by the Wilson interval method.

Inclusion Criteria:

• Aged above 18 years old.
• Requiring elective orotracheal intubation under general anesthesia in the OR.
• Suspected DI according to airway assessments ，and with low risk of difficult ventilation.
• Planning to use a Macintosh laryngoscope blade on the first attempt, whether direct or video laryngoscopy.
• Signed written informed consent.
• Willingness for the primary anesthesia team to participate.

Exclusion Criteria:

• Anterior neck lesions, masses, lacerations, or subcutaneous emphysema.
• A history of neck operation or tracheotomy.
• Allergies to ultrasound coupling gel.