Upper Airway Ultrasound to Predict Difficult Laryngoscopy in Neonates and Infants

March 2, 2026 updated by: Children's Hospital of Philadelphia

Upper Airway Ultrasound to Predict Difficult Airway Management in Neonates and Infants: A Prospective Observational Study

Upper airway ultrasound (UA-US) has been utilized in adults to predict difficult laryngoscopy (Cormick-Lehane view 3 or 4) and difficult tracheal intubation (DTI) (≥3 intubation attempts) and with moderate-to-high sensitivity and specificity. This bedside technique is reproducible, easy-to-do without any additional radiation risk, and was added to the most recent American Society of Anesthesiologists (ASA) Practice Guidelines for Difficult Airway Management in Adults. However, UA-US has only been applied to older children ages 5-12 and has not been examined in neonates and infants. Thus, the aim of this observational study using UA-US to predict difficult laryngoscopy and tracheal intubation in neonates and infants presenting for diagnostic, procedural or surgical care under general anesthesia requiring endotracheal intubation.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Detailed Description

Neonates and infants have a higher incidence of difficult laryngoscopy and DTI compared to older children and adults. Classical methods of screening for difficult laryngoscopy or DTI in adults, such as a Mallampati score, thyromental distance, and neck circumference are poorly applied to our smallest patients. UA-US has emerged as a technique to measure several UA parameters at the bedside with impressive sensitivity and specificity for identifying a difficult airway in adult patients, with higher UA-US measurements correlating with higher Cormick-Lehane laryngoscopy scores. UA-US was recently added to the 2022 ASA Practice Guidelines for Difficult Airway Management, specifically distance from the skin to the epiglottis (DSE), distance from the skin to the hyoid bone (DSHB), and tongue thickness (TTh). While UA-US has been minimally studied in children, one study showed high positive and negative predictive values for DTI with DSE and hyomental distance (HMD) in children aged 5-12 years. UA-US has the potential to identify unanticipated difficult airways in neonates and infants but has not been studied in this vulnerable population.

Despite the adoption of video laryngoscopy (VL) for intubation of neonates and infants in many clinical settings, there remains a substantial incidence of difficult glottic exposure and DTI. Garcia-Marcinkiewicz et al. found an incidence of difficult laryngoscopy, defined as a percentage of glottic opening (POGO) score <100 in 33% of neonates and infants intubated with VL. The NEonatal and Children AudiT of Anaesthesia pRactice (NECTARINE) trial, a multicenter prospective study performed in Europe, found a DTI rate of 5.8% amongst neonates and infants requiring intubation for a surgical procedure. Of these difficult intubations, nearly 70% were unplanned, unanticipated difficult airways. Repeated attempts at intubation are correlated with an increased rate of serious complications like severe hypoxemia, airway trauma, and cardiac arrest, and those youngest in age are at highest risk. Unanticipated difficult airways are more likely to increase the number of tracheal intubation attempts required for success.

UA-US could be utilized as a non-invasive, bedside tool to screen neonates and infants for unanticipated difficult laryngoscopy and intubation, facilitating multidisciplinary airway planning, in and out of the operating room, potentially reducing the need for multiple intubation attempts and patient harm. However, UA-US has never been applied to this patient population. This would be an innovative application of a point-of-care ultrasound modality that is currently being utilized in multiple adult care settings (operating room, emergency department and intensive care units). UA-US has similarly broad potential functions in pediatric medicine that are currently being underutilized.

As this is a novel application of this technique in this patient population, the aims of this study are to examine the differences in distribution of UA-US measurements between neonates and infants with and without difficult glottic exposure (POGO score 0-50%) with VL. In adult studies, direct laryngoscopy (DL) is commonly used and difficulty of laryngoscopy typically graded using the Cormick-Lehane grading scale (I-IV). However, airway management differs in neonates and infants. The First-Attempt Success Rate of Video Laryngoscopy In Small Infants (VISI) trial performed in 2020 found a significantly higher success rate of first-intubation success utilizing VL over DL (93% versus 88%, P=0.024.) in neonates and infant presenting for tracheal intubation during surgery. As a result, VL is considered standard of care in this patient population. Further, to test whether UA-US measurements correlate accurately to difficult laryngoscopy and DTI, it is pertinent to standardize the intubation technique to reduce confounding.

The investigators hypothesize that higher UA-US values will be associated with higher odds of having worse POGO scores in neonates and infants intubated with VL.

Study Type

Observational

Enrollment (Estimated)

180

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Children's Hospital of Philadelphia

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Neonates and infants presenting for diagnostic or procedural care under general anesthesia requiring oral endotracheal intubation with video laryngoscopy and neuromuscular blockade.

Description

Inclusion Criteria:

  • Neonates (chronological age 30 days) and infants (31 days to 365 days)
  • ASA physical status I-IV
  • Oral endotracheal intubation for surgical, diagnostic or interventional procedures with neuromuscular blockade
  • Video laryngoscopy
  • Patients with previously classified non-difficult airway (previous easy intubation)
  • Patients with a previously classified difficult airway
  • Patients with congenital heart disease
  • Parental/guardian permission

Exclusion Criteria:

  • ASA ≥V
  • Emergency procedure
  • Unable to be placed in supine position for study ultrasound
  • Need for rapid sequence induction

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
neonates and infants requiring oral tracheal intubation with VL and neuromuscular blockade

The investigator will perform 6 UA-US measurements will be obtained with a high frequency linear array or curvilinear US probe following induction of anesthesia but prior to laryngoscopy or TI: distance from the skin to the epiglottis, distance from the skin to the hyoid bone, distance from skin to vocal cords, hyomental distance, tongue thickness, and tongue cross-sectional area.

Following UA-US, oral tracheal intubation will occur with VL and neuromuscular blockade as clinical standard of care. At the time of tracheal intubation, the study team will record the percent of glottic opening (POGO) score and additional study endpoints.
Other: Upper airway ultrasound
The investigator will perform 6 UA-US measurements will be obtained with a high frequency linear array or curvilinear US probe following induction of anesthesia but prior to laryngoscopy or TI: distance from the skin to the epiglottis, distance from the skin to the hyoid bone, distance from skin to vocal cords, hyomental distance, tongue thickness, and tongue cross-sectional area.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percentage of Glottic Opening (POGO) score
Time Frame: From enrollment to the end of successful tracheal intubation, approximately 30 minutes.
(0-25%; >25-50%; >50-75%; >75-100%). Lower POGO scores correlate with a worse view of the glottic opening (Cormack-Lehane III-IV) and difficult laryngoscopy.
From enrollment to the end of successful tracheal intubation, approximately 30 minutes.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Difficult tracheal intubation
Time Frame: From enrollment to the end of successful tracheal intubation, approximately 30 minutes.
> or = 3 intubation attempts
From enrollment to the end of successful tracheal intubation, approximately 30 minutes.
Time to successful intubation in seconds
Time Frame: From enrollment to the end of successful tracheal intubation, approximately 30 minutes.
Time from laryngoscope insertion to confirmation of endotracheal tube (ETT) placement/end tidal capnography
From enrollment to the end of successful tracheal intubation, approximately 30 minutes.
First attempt success
Time Frame: From enrollment to the end of successful tracheal intubation, approximately 30 minutes.
Number of intubations successful on the first-attempt
From enrollment to the end of successful tracheal intubation, approximately 30 minutes.
Use of advancement maneuvers
Time Frame: From enrollment to the end of successful tracheal intubation, approximately 30 minutes.
Shift blade left, laryngoscope blade retracted or pulled back blade, ETT receded and then advanced
From enrollment to the end of successful tracheal intubation, approximately 30 minutes.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Children's Hospital of Philadelphia

Investigators

  • Principal Investigator: Elizabeth M O'Brien, MD, MAS, Children's Hospital of Philadelphia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 2, 2026

Primary Completion (Estimated)

December 31, 2027

Study Completion (Estimated)

December 31, 2027

Study Registration Dates

First Submitted

February 24, 2026

First Submitted That Met QC Criteria

February 26, 2026

First Posted (Actual)

March 3, 2026

Study Record Updates

Last Update Posted (Actual)

March 4, 2026

Last Update Submitted That Met QC Criteria

March 2, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 25-023870
  • PRJ-00001922 (Other Grant/Funding Number: Children's Hospital of Philadelphia Department of Anesthesiology and Critical Care Medicine Internal Pilot Grant)

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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