Threshold, AUC-ROC, Sensitivity, Specificity, Positive and Negative Likelihood Ratios, and Positive and Negative Predictive Values of Endotracheal Pressure Induced by a Ptr,stim, Diaphragm Thickening Fraction, Parasternal Intercostal Muscle Thickening Fraction, and Parasternal Intercostal Muscle Thickening Fraction/Diaphragm Thickening Fraction Ratio to Predict Failure of the Spontaneous Breathing Trial