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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Diagnostic Imaging, Intubation; Difficult or Failed, Intubation Complication, Ultrasonography

Intervention / Treatment
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* Procedure: Ultrasonography
* Procedure: Direct visualization


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Ultrasonography + direct visualization<br>To detect using ultrasonography assisted direct visualization. | Procedure: Ultrasonography<br>* The transducer will be placed over the anterior neck just above the suprasternal notch, in the transverse orientation. The position of the transducer could be adjusted to visualize both the esophagus and trachea. It will be considered as esophageal intubation if esophageal dilation or double-tract sign are noted.<br>Procedure: Direct visualization<br>* While performing the intubation, the intubator will report ETI if visualizing the tracheal tube passing through the glottis. Otherwise, it will be regarded as esophageal intubation.<br>|
| Experimental: Direct visualization<br>To detect using direct visualization. | Procedure: Direct visualization<br>* While performing the intubation, the intubator will report ETI if visualizing the tracheal tube passing through the glottis. Otherwise, it will be regarded as esophageal intubation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The specificity. | The detected negative/ true negative. According to the purpose of the proposed study, we will define esophageal intubation as positive, and endotracheal intubation as negative. In group direct visualization, positive and negative are defined as absent and present visualization of the tracheal tube passing through the glottis, respectively. In group ultrasonography assisted direct visualization, positive is defined as sonography detection of esophageal dilation or double-tract sign, and negative is defined as direct visualization of the tracheal tube passing through the glottis. If neither the specific US nor the clear visualization is noted, the intubator and the sonographer will discuss and reach a consistent conclusion in three seconds. | Upon or within three minutes of performing intubation. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The sensitivity. | The detected positive/ true positive. According to the purpose of the proposed study, we will define esophageal intubation as positive, and endotracheal intubation as negative. In group direct visualization, positive and negative are defined as absent and present visualization of the tracheal tube passing through the glottis, respectively. In the group using ultrasonography-assisted direct visualization, positive is defined as sonography detection of esophageal dilation or double-tract sign, and negative is defined as direct visualization of the tracheal tube passing through the glottis. If neither the specific US nor the clear visualization is noted, the intubator and the sonographer will discuss and reach a consistent conclusion in three seconds. | Upon or within three minutes of performing intubation. | 
| The positive likelihood ratio. | The positive likelihood ratio is calculated as sensitivity/(1 - specificity). According to the purpose of the proposed study, we will define esophageal intubation as positive, and endotracheal intubation as negative. In group direct visualization, positive and negative are defined as absent and present visualization of the tracheal tube passing through the glottis, respectively. In the group using ultrasonography-assisted direct visualization, positive is defined as sonography detection of esophageal dilation or double-tract sign, and negative is defined as direct visualization of the tracheal tube passing through the glottis. If neither the specific US nor the clear visualization is noted, the intubator and the sonographer will discuss and reach a consistent conclusion in three seconds. | Upon or within three minutes of performing intubation. | 
| The negative likelihood ratio. | The negative likelihood ratio is calculated as (1 - sensitivity)/specificity. According to the purpose of the proposed study, we will define esophageal intubation as positive, and endotracheal intubation as negative. In group direct visualization, positive and negative are defined as absent and present visualization of the tracheal tube passing through the glottis, respectively. In the group using ultrasonography-assisted direct visualization, positive is defined as sonography detection of esophageal dilation or double-tract sign, and negative is defined as direct visualization of the tracheal tube passing through the glottis. If neither the specific US nor the clear visualization is noted, the intubator and the sonographer will discuss and reach a consistent conclusion in three seconds. | Upon or within three minutes of performing intubation. | 
| The diagnostic odds ratio. | Positive likelihood ratios/Negative likelihood ratio. According to the purpose of the proposed study, we will define esophageal intubation as positive, and endotracheal intubation as negative. In group direct visualization, positive and negative are defined as absent and present visualization of the tracheal tube passing through the glottis, respectively. In the group using ultrasonography-assisted direct visualization, positive is defined as sonography detection of esophageal dilation or double-tract sign, and negative is defined as direct visualization of the tracheal tube passing through the glottis. If neither the specific US nor the clear visualization is noted, the intubator and the sonographer will discuss and reach a consistent conclusion in three seconds. | Upon or within three minutes of performing intubation. | 
| The positive predictive value. | Cases of true positive among detective positive/ cases of detective positive. According to the purpose of the proposed study, we will define esophageal intubation as positive, and endotracheal intubation as negative. In group direct visualization, positive and negative are defined as absent and present visualization of the tracheal tube passing through the glottis, respectively. In the group using ultrasonography-assisted direct visualization, positive is defined as sonography detection of esophageal dilation or double-tract sign, and negative is defined as direct visualization of the tracheal tube passing through the glottis. If neither the specific US nor the clear visualization is noted, the intubator and the sonographer will discuss and reach a consistent conclusion in three seconds. | Upon or within three minutes of performing intubation. | 
| The negative predictive value | Cases of true negative among detective negative/ cases of detective negative. According to the purpose of the proposed study, we will define esophageal intubation as positive, and endotracheal intubation as negative. In group direct visualization, positive and negative are defined as absent and present visualization of the tracheal tube passing through the glottis, respectively. In the group using ultrasonography-assisted direct visualization, positive is defined as sonography detection of esophageal dilation or double-tract sign, and negative is defined as direct visualization of the tracheal tube passing through the glottis. If neither the specific US nor the clear visualization is noted, the intubator and the sonographer will discuss and reach a consistent conclusion in three seconds. | Upon or within three minutes of performing intubation. | 
| The detective self-confidence grade | The detective self-confidence grade will be provided on a four-point scale of 1= unsure, 2= less sure, 3= quite sure, and 4= sure. | Upon or within three minutes of performing intubation. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ultrasonography, Intubation, Intratracheal, Esophageal intubation, Difficult intubation