Combined Lung and Diaphragmatic Ultrasound to Predict Respiratory Failure in Blunt Chest Trauma

September 2, 2026 updated by: Ahmed Mohamed Ahmed Mohamed, Assiut University

The Additive Value of Diaphragmatic Ultrasound to Lung Ultrasound for Early Prediction of Hypoxemic Respiratory Failure Following Isolated Blunt Chest Trauma: A Prospective Cohort Study

Blunt chest trauma is a leading cause of emergency hospital visits and can result in severe breathing complications such as hypoxemic respiratory failure. While computed tomography (CT) scans provide detailed imaging of the chest, their routine use is limited by radiation exposure, high cost, and the inability to perform frequent bedside monitoring. Bedside lung ultrasound (LUS) is commonly used to detect structural injuries like lung contusions or collapsed lungs, but it cannot assess how well the breathing muscles are working. Because acute respiratory failure after chest trauma involves both lung tissue damage and impaired breathing muscle mechanics, combining lung ultrasound with diaphragmatic ultrasound may improve early risk assessment.

The primary purpose of this prospective cohort study is to determine whether combining point-of-care lung ultrasound with diaphragmatic ultrasound provides better early prediction of hypoxemic respiratory failure than lung ultrasound alone in adult patients with isolated blunt chest trauma.

Participants will undergo bedside lung ultrasound, diaphragmatic ultrasound, and arterial blood gas testing at four standardized time points: upon hospital admission (baseline), and at 6, 12, and 24 hours after admission. The lung ultrasound examination assesses the degree of lung tissue injury using a standardized 12-zone Lung Ultrasound Score (LUS). Diaphragmatic ultrasound measures muscle movement (diaphragmatic excursion) and contraction strength (diaphragm thickening fraction). Arterial blood gas results will be used to track oxygenation via the PaO2/FiO2 ratio, with a ratio of 300 mmHg or lower defining hypoxemic respiratory failure. All participants will also receive a standard-of-care chest CT scan as a reference comparison.

The study aims to evaluate whether this non-invasive, radiation-free bedside approach helps emergency physicians identify high-risk patients earlier, guiding timely respiratory support and intensive care triage while minimizing the need for repeated CT scans.

Study Overview

Study Type

Observational

Enrollment (Estimated)

130

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

N/A

Sampling Method

Non-Probability Sample

Study Population

Adult patients presenting to the emergency room of the Trauma Unit at Assiut University Hospitals within 24 hours of sustaining isolated blunt chest trauma.

Description

Inclusion Criteria:

  • Age 18 years or older
  • Presentation to the trauma unit within 24 hours of injury
  • Diagnosed with isolated blunt chest trauma
  • Willingness to participate with written informed consent provided by the patient or legally authorized representative

Exclusion Criteria:

  • Penetrating chest trauma
  • Immediate endotracheal intubation before baseline ultrasound assessment
  • Massive hemothorax or tension pneumothorax requiring immediate emergency intervention prior to ultrasound evaluation
  • Inadequate ultrasound acoustic window due to extensive subcutaneous emphysema or severe obesity
  • Known preexisting chronic pulmonary disease (e.g., chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, bronchial asthma)
  • Known preexisting cardiac disease (e.g., ischemic heart disease, rheumatic heart disease)
  • Known neuromuscular disorders affecting respiratory muscles
  • Previous thoracic surgery affecting diaphragmatic excursion or documented diaphragmatic paralysis
  • Pregnancy
  • Refusal to provide informed consent or withdrawal from the study

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
Isolated Blunt Chest Trauma Patients
Adult patients presenting within 24 hours of isolated blunt chest trauma. All participants undergo serial bedside point-of-care lung ultrasound (12-zone protocol to calculate total LUS) and diaphragmatic ultrasound (measuring diaphragmatic excursion [DE] and diaphragm thickening fraction [DTF]), paired with arterial blood gas analysis to calculate the PaO₂/FiO₂ ratio at four predefined time points: admission (baseline), 6 hours, 12 hours, and 24 hours post-admission. Patients also undergo baseline chest CT imaging as a standard reference.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Ratio of Arterial Oxygen Partial Pressure to Fractional Inspired Oxygen (PaO2/FiO2)
Time Frame: 1 day
PaO2/FiO2 ratio will be calculated using arterial blood gas (ABG) analysis. Hypoxemic respiratory failure is defined as a PaO2/FiO2 ratio of 300 mmHg or less. Values will be measured in mmHg.
1 day

Collaborators and Investigators

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

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 (Estimated)

October 1, 2026

Primary Completion (Estimated)

October 1, 2027

Study Completion (Estimated)

November 1, 2027

Study Registration Dates

First Submitted

September 2, 2026

First Submitted That Met QC Criteria

September 2, 2026

First Posted (Actual)

September 8, 2026

Study Record Updates

Last Update Posted (Actual)

September 8, 2026

Last Update Submitted That Met QC Criteria

September 2, 2026

Last Verified

September 1, 2026

More Information

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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