Despite improvement in the quality of intensive care, the incidence of failed extubation is 5%–30%. Several indices have been used in the past to predict successful weaning and extubation. However, none of these indices have a good positive predictive value. Therefore, it is expected that the inclusion of ultrasound of the chest and heart would be successful in identifying the patients who will likely fail the weaning trial. Critical illness produces diaphragmatic dysfunction which can contribute to weaning failure. The inability of heart to cope with the increased load of work of breathing is also responsible for re-intubation. Therefore, we planned this study with the aim to evaluate the association of parameters derived from the ultrasound of the diaphragm, and from bedside echocardiography with successful extubation.

Critically ill adult patients who are mechanically ventilated for more than 48 hours will be screened for the study. Patients who fulfill the “readiness to wean criteria” and initiated on spontaneous breathing trial will be enrolled. We intend to enroll 130 patients in the study. Diaphragmatic Ultrasound and Echocardiography will be performed during 30 minutes of Spontaneous Breathing Trial (SBT). Primary Outcome of the study is to calculate the Area under Receiver Operating Curves (AUROC), sensitivity and specificity of Diaphragm ultrasonography and ECHO- guided parameters for assessing their association with successful tracheal extubation. Secondary outcomes include incidence of successful extubation (defined as the ability to tolerate spontaneous breathing for 48 hours without need for endotracheal re- intubation), length of ICU stay and in-hospital mortality. Receiver Operator Curve (ROC) analysis will be done to determine optimal cut off values for each parameter. The AUROC, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the parameters obtained will be calculated to analyze their association with successful extubation. This being an observational study, extubation will be carried out as per the standard protocol and the investigators will not take part in that decision.