Ultrasound to Predict Difficult Airway

Evaluation of Upper Airway Ultrasound-derived Indexes as Predictors of Difficult Airway

Upper airway ultrasound is a valuable, non-invasive, simple, and portable point of care tool for evaluation of the airway, even in the presence of anatomic distortion caused by pathology or trauma. The ultrasound technology is being increasingly adopted in modern anesthesiology practice. As early as in 1984, some authors have recommended its use to guide venous cannulation, because it shortens procedural times, reduces the number of failed puncture attempts, and minimizes complications. On the other hand, ultrasound-guided techniques are considered the gold standard for peripheral nerve blocks.

As ultrasound becomes more widespread, it is important to for anesthesiologists to be aware of the expanding applications of this technology. Current and potential future applications of ultrasound in anesthesiology are wide and include regional anesthesia, neuraxial and chronic pain procedures, vascular access, airway assessment, lung ultrasound, ultrasound neuro-monitoring, gastric ultrasound, focused transthoracic echography, trans-esophageal echocardiography and vascular Doppler flow assessment. The major disadvantage is inter-observer variability, and the fact that it requires is a unique skill that requires continuing training and experience to master the technology. In order to be successful with this technique, it is important to develop a thorough understanding of the sonoanatomy. The normal or abnormal structures need to be imaged and interpreted before any intervention.

Airway management is one of the most important tasks for anesthesiologists. Access to the airway should be safe, fast and efficient. Appropriate planning is crucial to avoid morbidity and mortality when difficulty is anticipated. Inability to maintain airway ventilation is a life-threatening situation that may warrant emergent surgical access to prevent devastating consequences. A thorough assessment of the airway is recommended to predict difficulty. Multiple clinical predictors have been used in clinical practice; however, most of them are associated with low predictive values. In consequence, a comprehensive airway examination that incorporates both quantitative and qualitative tests increases the probability of predicting difficult intubation. Regardless of the method of airway evaluation, it is important to acknowledge that clinical airway assessment is not fully accurate and can produce both false-negative and false-positive results.

There is a growing academic interest in the ability of ultrasound to determine airway size to estimate appropriate endotracheal tube size. Ultrasound enables us to identify important sonoanatomy of the upper airway including thyroid cartilage, epiglottis, cricoid cartilage, cricothyroid membrane, tracheal cartilages, and esophagus. Transverse and parasagittal views can help diagnose supraglottic, glottic and infraglottic airway conditions and aid the anesthesiologist in airway management. Ultrasonography has brought a paradigm shift in the practice of airway management. With increasing awareness, portability, accessibility and further sophistication in technology, it is likely to find a place in routine airway management.

Study Overview

• Status: Recruiting
• Conditions: Difficult Intubation
• Intervention / Treatment: Diagnostic test: External ultrasound evaluation of the airway

• Study Type: Observational
• Enrollment (Anticipated): 420

Contacts and Locations

Study Locations

• United States
  • Georgia
    • Augusta, Georgia, United States, 30912
      • Recruiting
      • Augusta University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patient scheduled for elective surgery under general anesthesia in whom tracheal intubation is planned.

Description

Inclusion Criteria:

• Elective surgery
• Age older than 18 years

Exclusion Criteria:

• Emergency surgery
• Nasal intubation
• Intubation with fiberoptic scope or glidescope
• Intubation without laryngoscopy
• Awake intubation
• Allergy to ultrasound gel

Study Plan

How is the study designed?

Design Details

• Observational Models: Other
• Time Perspectives: Prospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patient scheduled for general anesthesia with intubation; Patients in this group (only group) will have clinical airway assessment and external ultrasound assessment of the airway	Diagnostic test: External ultrasound evaluation of the airway; Patients scheduled to have surgery under general anesthesia in whom tracheal intubation is planned, will have a clinical and ultrasound assessment of the airway before surgery. Information regarding laryngoscopy in the operating room will be recorded.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ultrasound depth of the tongue	With curvilinear ultrasound probe in longitudinal position over upper neck, the distance from probe to tongue will be measured.	10 minutes
Degree of glottic visualization	During laryngoscopy, percentage of glottic opening will be recorded	10 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ultrasound depth of cricoid cartilage	With curvilinear ultrasound probe in longitudinal position over upper neck, the distance from probe to the cricoid cartilage will be measured.	10 minutes

Collaborators and Investigators

• Sponsor: Augusta University

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2019
• Primary Completion (Anticipated): January 1, 2023
• Study Completion (Anticipated): March 1, 2023

Study Registration Dates

• First Submitted: December 26, 2018
• First Submitted That Met QC Criteria: December 26, 2018
• First Posted (Actual): December 28, 2018

Study Record Updates

• Last Update Posted (Actual): July 22, 2021
• Last Update Submitted That Met QC Criteria: July 21, 2021
• Last Verified: July 1, 2021

More Information

Terms related to this study

• Other Study ID Numbers: 1218610

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No