Prediction of Weaning Outcome from Mechanical Ventilation Using Ultrasound Assessment of Parasternal Intercostal Muscle Thickness

Background: Monitoring the function of parasternal intercostal muscles provides information on respiratory load and capacity and thus can be a weaning monitoring tool.Objective: The goal was to study the diagnostic accuracy of parasternal intercostal muscle thickness fraction (PICTF%) as a predictor of weaning.Materials and methods: A prospective observational study on consecutively admitted patients who were intubated and mechanically ventilated for a duration of at least 48 hours was carried out. When an SBT was planned by the treating physician, the study examiner performed the ultrasound measurements of parasternal intercostal muscle thickness (inspiration and expiration) and thickening fraction using M-mode ultrasonography (USG). The PICTF% was calculated as "(peak inspiratory thickness - end-expiratory thickness)/end-expiratory thickness) x 100." Weaning failure was defined if the patient had a failed spontaneous breathing trial (SBT) or the need for a reintubation within 48 hours following extubation. The SBT failure was defined as the need to connect the patient back to the ventilator prior to its completion due to any reason as decided by the clinician.Results: Of 81 screened patients, 60 patients met the inclusion criteria, of whom 49 patients had successful SBT, and 48 patients could be successfully extubated. The PMTF% cut-off value more than or equal to 15.38% was associated with the best sensitivity (75%) and specificityConclusion: The PICTF% has a good diagnostic accuracy in predicting weaning failure.