Parasternal Intercostal Ultrasound vs RSBI for Weaning Prediction

NCT07144878 | Completed

• 1 other identifier: MD 3-11-2023
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

Mechanical ventilation is essential in the management of critically ill patients, but deciding the proper time to wean and extubate remains a significant challenge. Extubation failure is associated with poor outcomes, including prolonged intensive care unit stay, higher risk of complications, and increased mortality. The rapid shallow breathing index (RSBI) is widely used to predict weaning readiness, but its predictive accuracy is limited. Recently, ultrasound evaluation of respiratory muscles, particularly the parasternal intercostal muscle, has been proposed as a promising bedside tool to assess respiratory effort and load. This comparative clinical trial was conducted on adult intensive care unit patients at Benha University Hospital who were mechanically ventilated for ≤24 hours and ready for a spontaneous breathing trial. Each patient underwent both rapid shallow breathing index (RSBI) measurement and parasternal intercostal muscle ultrasound prior to the trial. Patients were classified into successful or failed weaning groups based on trial outcome. The study compared the diagnostic accuracy of both methods and aimed to determine whether ultrasound assessment of the parasternal intercostal muscle offers a more reliable predictor of weaning success than rapid shallow breathing index (RSBI).

Conditions

Respiratory Insufficiency; Weaning, Ventilator; Respiration, Artificial; Intensive Care Units; Respiratory Muscles

Keywords

Mechanical ventilation; Weaning from ventilation; Extubation outcome; Rapid Shallow Breathing Index (RSBI); Parasternal intercostal muscle ultrasound; Respiratory muscle dysfunction; Spontaneous breathing trial (SBT); Critical care

Outcome Measures

Primary Outcomes (1)

• Diagnostic accuracy of parasternal intercostal muscle thickening fraction measured by ultrasound versus Rapid Shallow Breathing Index for predicting successful weaning from mechanical ventilation

  The outcome was assessed by comparing two diagnostic measurements: (1) parasternal intercostal muscle thickening fraction, calculated as the difference between end-inspiratory and end-expiratory muscle thickness divided by end-expiratory thickness, measured using bedside ultrasound; and (2) the Rapid Shallow Breathing Index, calculated as respiratory rate divided by tidal volume, recorded from ventilator-displayed values under standardized zero-support settings. Predictive accuracy for successful weaning was evaluated using receiver operating characteristic analysis, including sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve. Successful weaning was defined as tolerating a 30-minute spontaneous breathing trial without signs of failure.

  Baseline, immediately prior to the spontaneous breathing trial

Secondary Outcomes (2)

• Sensitivity and specificity of parasternal intercostal muscle thickening fraction and Rapid Shallow Breathing Index in predicting successful weaning

  Baseline, immediately prior to the spontaneous breathing trial

• Comparison of area under the receiver operating characteristic curve between parasternal intercostal muscle thickening fraction and Rapid Shallow Breathing Index

  Baseline, immediately prior to the spontaneous breathing trial

Study Arms (1)

Parasternal Intercostal Ultrasound and RSBI Assessment

OTHER

All enrolled patients underwent ultrasonographic assessment of the parasternal intercostal muscle thickness and calculation of thickening fraction, as well as measurement of the Rapid Shallow Breathing Index (RSBI) using standard ventilator settings. These assessments were performed prior to a 30-minute spontaneous breathing trial. Patients were subsequently classified into successful or failed weaning groups based on trial outcome.

Diagnostic Test: Parasternal Intercostal Ultrasound and RSBI Assessment

Interventions

Parasternal Intercostal Ultrasound and RSBI Assessment DIAGNOSTIC_TEST

Participants underwent ultrasonographic evaluation of the parasternal intercostal muscle using a high-frequency linear probe to measure thickness and the thickening fraction during respiration. In addition, the Rapid Shallow Breathing Index was calculated from ventilator-displayed values under standardized settings: pressure support equal to zero centimeters of water and positive end-expiratory pressure equal to zero centimeters of water. Both assessments were performed immediately prior to a spontaneous breathing trial to evaluate their predictive accuracy for successful weaning from mechanical ventilation.

Parasternal Intercostal Ultrasound and RSBI Assessment

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 18 years or older
• Both sexes
• Patients invasively mechanically ventilated for up to 24 hours and ready to undergo a spontaneous breathing trial
• Patients considered ready for spontaneous breathing trial if all of the following were met:
• Alert and afebrile
• Fraction of inspired oxygen less than 50 percent
• Positive end-expiratory pressure less than or equal to 8 centimeters of water
• Ratio of arterial oxygen partial pressure to fraction of inspired oxygen greater than 200
• Arterial blood pH between 7.35 and 7.45
• Respiratory rate less than or equal to 35 breaths per minute
• Hemodynamically stable without vasopressor support

You may not qualify if:

• Age younger than 18 years
• Pregnancy
• Surgical dressings near or over the sternum that prevent ultrasound examination
• Body mass index less than 18.5 kilograms per square meter (underweight)
• Body mass index greater than or equal to 40 kilograms per square meter (morbid obesity)
• Primary neuromuscular diseases

Sponsors & Collaborators

• Benha University: lead

Study Sites (1)

Benha University Hospital

Banhā, Egypt

Location

MeSH Terms

Conditions

Respiratory Insufficiency; Respiratory Aspiration

Condition Hierarchy (Ancestors)

Respiration Disorders; Respiratory Tract Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Masking Details: No masking was applied. Both investigators and treating clinicians were aware of the diagnostic tests performed.
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Lecturer of Critical Care Medicine

Model Details: All enrolled patients underwent both RSBI measurement and parasternal intercostal muscle ultrasound prior to spontaneous breathing trial, and outcomes were analyzed by weaning success or failure.

Study Record Dates

• First Submitted: February 21, 2025
• First Posted: August 28, 2025
• Study Start: October 3, 2023
• Primary Completion: April 1, 2024
• Study Completion: June 25, 2024
• Last Updated: August 28, 2025

Record last verified: 2025-08

Locations

EG (1)