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).
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
50
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.
Benha University Hospital
Banhā, Egypt
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.
Time frame: Baseline, immediately prior to the spontaneous breathing trial
Sensitivity and specificity of parasternal intercostal muscle thickening fraction and Rapid Shallow Breathing Index in predicting successful weaning
The sensitivity, specificity, positive predictive value, and negative predictive value of parasternal intercostal muscle thickening fraction measured by ultrasound and Rapid Shallow Breathing Index were calculated to assess their ability to predict successful weaning from mechanical ventilation.
Time frame: 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
Receiver operating characteristic curve analysis was performed to compare the diagnostic performance of parasternal intercostal muscle thickening fraction measured by ultrasound and Rapid Shallow Breathing Index. The area under the curve, accuracy, and statistical significance of the difference between the two methods were reported.
Time frame: Baseline, immediately prior to the spontaneous breathing trial
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