Comparison of Ultrasound Techniques for Assessment of Endotracheal Tube Placement

Comparison of Three Point-of-care Ultrasound Techniques to Confirm Endotracheal Tube Placement: a Randomized Clinical Trial

This study is a single-center, randomized clinical trial conducted in an emergency department on intubated patients with rapid sequence intubation. Two sonographers will independently verify the accuracy of the intubation site using the assigned intubation method (tracheal, lung-sliding, or diaphragm) according to the randomization sequence. Each sonographer will be blinded to the other verification methods (physical examination, end-tidal carbon dioxide) being used. The study's primary objective is to compare the diagnostic accuracy of different intubation techniques.

Study Overview

• Status: Completed
• Conditions: Intubation; Difficult or Failed
• Intervention / Treatment: Diagnostic test: Tracheal Ultrasound; Diagnostic test: Diaphragm Ultrasound; Diagnostic test: Lung Ultrasound

Detailed Description

In emergency medicine, endotracheal intubation (ETI) is commonly performed for patients who require airway management due to acute respiratory failure, inadequate oxygenation or ventilation, or an inability to protect the airway resulting from altered consciousness. When ETI is performed outside of a cardiac arrest scenario, a series of steps are followed to optimize the procedure. These steps aim to prevent hypoxia, maintain hemodynamic stability, reduce the risk of aspiration, and increase the success rate of ETI. This methodical approach is known as Rapid Sequence Intubation (RSI). RSI involves preparing the necessary and auxiliary equipment, administering premedication, ensuring oxygenation, and applying anesthetic and neuromuscular blocking agents, followed by the placement of the endotracheal tube (ETT). The procedure concludes with confirming the ETT's placement and providing post-intubation care.

The primary goal of ETI is to position the ETT through the vocal cords into the trachea, ensuring that both lungs are ventilated effectively. Incorrect or unrecognized endobronchial intubation can result in hypoventilation and collapse of the non-ventilated lung, while the over-ventilated lung may suffer barotrauma or pneumothorax. Unrecognized esophageal intubation, on the other hand, can lead to failure in ventilation, resulting in hypoxia and subsequent complications, including brain damage and other morbidities. Therefore, ensuring the correct placement of the ETT is crucial to avoid serious adverse outcomes.

Various methods have been described to confirm correct ETT placement, including direct visualization during intubation, observation of chest wall movements, bilateral auscultation of lung sounds, end-tidal carbon dioxide (EtCO2) monitoring, fiberoptic bronchoscopy, and chest X-ray. Among these, capnography is considered the gold standard. However, in specific clinical situations, EtCO2 monitoring may be unreliable. Patients in cardiac arrest, patients with severe hypotension, pulmonary embolism, or poor pulmonary reserve may present lower than expected EtCO2 values. Similarly, gastric insufflation, using antacids, or consuming carbonated beverages may result in false-positive readings.

The American College of Emergency Physicians (ACEP) guidelines recommend the use of additional confirmation methods after ETT placement. Ultrasound (US) has emerged as a relatively new technique for confirming ETI. Its advantages include being non-invasive, portable, rapid, and capable of providing real-time, accurate results. Additionally, the US is unaffected by environmental noise, which can be challenging in noisy environments such as the emergency department. It is also not influenced by changes in pulmonary blood flow.

Several ultrasound techniques have been described to confirm ETT placement. The most commonly used methods include direct visualization of the ETT during intubation (tracheal ultrasound), detection of the "lung sliding" sign via lung ultrasound to indicate lung aeration and bilateral identification of diaphragmatic movement. Tracheal ultrasound can detect esophageal intubation before ventilation begins, preventing unnecessary gastric insufflation and its associated complications. The lung sliding sign and bilateral diaphragmatic movement techniques can help identify endobronchial intubation by visualizing pleural and diaphragmatic movement, respectively, thereby complementing tracheal ultrasound and reducing the risk of missed endobronchial intubation.

A comprehensive literature review revealed that no studies have directly compared these three ultrasound methods. Therefore, this study aims to evaluate the effectiveness of these three ultrasound techniques in confirming ETT placement and to compare the time required for each method. A secondary objective is to compare the time spent using ultrasound with that of auscultation and capnography. Additionally, this study will assess the ability of each ultrasound technique to detect tracheal intubation and, if present, accidental esophageal intubation across all patients.

• Study Type: Interventional
• Enrollment (Actual): 200
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye), 34687
    • Marmara University Pendik Training and Research Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients in the emergency department who require endotracheal intubation (ETI) based on the decision of the primary physician and are intubated using the rapid sequence intubation method.
• Patients aged >18 years will be included in the study.

Exclusion Criteria:

• Pregnant patients.
• Patients with a history of neck or chest surgery that may interfere with ultrasound evaluation.
• Patients with cervical spine disease or a history of surgery that could affect diaphragmatic movement.
• Patients diagnosed conditions such as pneumothorax that could affect lung ultrasound results, or those in whom pneumothorax is detected upon further evaluation,
• Patients who, after being enrolled, withdraw consent either personally or through a relative.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Tracheal Ultrasound; The success of endotracheal intubation (ETI) will be checked by tracheal ultrasonography. The primary outcome will be the placement of the endotracheal tube (ETT) in the trachea or esophagus. The secondary outcome will assess the duration of the ultrasound procedure. The time measurement will begin immediately after the placement of the ETT and will continue until a decision is made, via ultrasound, regarding whether the intubation is tracheal or esophageal.	Diagnostic test: Tracheal Ultrasound; In the clinic, one of the routinely used ultrasound machines, either the HM70 EVO Linear Probe (5-12 MHz) or the eSaote MyLab Seven Linear Probe (3-13 MHz), will be selected based on suitability for the procedure at the time. A linear transducer will be placed perpendicular to the trachea at the level of the cricoid membrane. During ETI, visualization of the ETT moving within the trachea, specifically behind the cricothyroid membrane, indicates successful intubation. In contrast, if the ETT is mistakenly placed in the esophagus, a double-lumen appearance lateral to the trachea, created by the ETT within the esophagus, suggests esophageal intubation.
Experimental: Lung Ultrasound; The success of ETI will be checked by lung ultrasonography. The primary outcome will be the placement of the ETT in the trachea or esophagus. The secondary outcome will assess endobronchial intubation and the duration of the ultrasound procedure. The time measurement will begin immediately after the placement of the ETT and will continue until a decision is made, via ultrasound, regarding whether the intubation is tracheal or esophageal.	Diagnostic test: Lung Ultrasound; In the clinic, one of the routinely used ultrasound machines, either the HM70 EVO Linear Probe (5-12 MHz) or the eSaote MyLab Seven Linear Probe (3-13 MHz), will be selected based on suitability for the procedure at the time. Following ETI, the presence of lung sliding will be evaluated using ultrasound with the aid of a linear probe. The transducer will be placed bilaterally along the mid-clavicular line, between the second and fifth intercostal spaces, in a coronal orientation. After the ETT is placed and ventilation is initiated, the movement of the visceral and parietal pleura will be assessed. The presence of sliding motion between these pleural layers during ventilation indicates successful intubation, whereas the absence of this movement suggests a failed intubation.; Other Names: Lung Sliding
Experimental: Diaphragm Ultrasound; The success of ETI will be checked by diaphragm ultrasonography. The primary outcome will be the placement of the ETT in the trachea or esophagus. The secondary outcome will assess endobronchial intubation and the duration of the ultrasound procedure. The time measurement will begin immediately after the placement of the ETT and will continue until a decision is made, via ultrasound, regarding whether the intubation is tracheal or esophageal.	Diagnostic test: Diaphragm Ultrasound; In the clinic, one of the routinely used ultrasound machines, either the HM70 EVO Curvilinear Probe (2-8 MHz) or the eSaote MyLab Seven Curvilinear Probe (1-8 MHz), will be selected based on suitability for the procedure at the time. Using a curvilinear transducer, the probe will be placed along the mid-axillary line, approximately at the seventh to ninth intercostal spaces, in a coronal orientation. The movement of the diaphragm during ventilation will be assessed over the spleen and liver. Diaphragmatic motion during ventilation indicates successful ETI, while the absence of bilateral diaphragmatic movement suggests esophageal intubation. If diaphragmatic movement is only observed on one side, it is indicative of endobronchial intubation.; Other Names: Diaphragm Excursion

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correct Classification of Endotracheal Tube Position	The primary outcome was correct classification of endotracheal tube position, tracheal or esophageal, by the assigned ultrasound technique. Classification was considered correct when the ultrasound finding agreed with the reference standard assessment performed by the treating physician using quantitative end tidal carbon dioxide monitoring together with bilateral chest auscultation.	Immediately after intubation, assessed within the first 5 minutes after the procedure.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Endotracheal Intubation Confirmation Time	The duration of each method used to confirm endotracheal intubation (ultrasonography, physical examination, and end-tidal carbon dioxide) will be recorded separately. The timing will start from the placement of the endotracheal tube and connection to the bag-valve mask, and will end once a determination-successful (tracheal intubation) or unsuccessful (esophageal intubation)-is made using the respective method. If the primary physician determines esophageal intubation, the remaining uncompleted methods will be discontinued to avoid disrupting the patient's routine management or causing harm. If the ultrasonography procedure is not completed, it will be considered unsuccessful. The timing will begin after the completion of intubation and connection to the bag-valve mask, and will continue until a decision is made. The total duration will be recorded.	Immediately after intubation, assessed within the first 5 minutes after the procedure.
Sonographer Confidence	After completing the procedure, the sonographer will rate their experience of confirming endotracheal tube position using ultrasound and their confidence in their interpretation on a 5-point Likert scale, ranging from 1 (not at all confident) to 5 (very confident).	Immediately after ultrasound, assessed within the first 5 minutes after the procedure.

Collaborators and Investigators

• Sponsor: Marmara University Pendik Training and Research Hospital
• Investigators: Study Director: Emre Kudu, MD, Marmara University Pendik Training and Research Hospital

Publications and helpful links

General Publications

• Kudu E, Korgan MB, Altun M, Yakin F, Karacabey S, Sanri E, Akoglu H, Denizbasi A. Comparison of three point-of-care ultrasound techniques to confirm endotracheal tube placement: A randomized clinical trial. Am J Emerg Med. 2026 Apr 26;106:55-61. doi: 10.1016/j.ajem.2026.04.039. Online ahead of print.

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2024
• Primary Completion (Actual): June 19, 2025
• Study Completion (Actual): June 19, 2025

Study Registration Dates

• First Submitted: October 22, 2024
• First Submitted That Met QC Criteria: October 23, 2024
• First Posted (Actual): October 24, 2024

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 11, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: emergency department; lung ultrasound; Ultrasonography; Endotracheal intubation; Rapid sequence intubation; point-of-care ultrasound; diaphragm ultrasound; End-tidal carbondioxide; transtracheal ultrasound
• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Pathological Conditions, Signs and Symptoms; Emergencies
• Other Study ID Numbers: 09.2024.629

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No