Speckle Tracking

The primary aim of this study is to evaluate the predictive value of the inspiratory regional diaphragmatic synchrony index (RDSI-insp) during PSV-SBT for first-attempt weaning failure. Secondary objectives include: (1) assessing the correlation between RDSI-insp and conventional respiratory mechanics and diaphragmatic ultrasound parameters such as RSBI, MIP/NIF, VC, CPF, P0.1, DE, and DTF; (2) comparing differences in RDSI and DPSI between successful and failed weaning groups during inspiration, end-inspiration, and expiration; (3) exploring the association of anterior diaphragmatic dyssynchrony index, posterior/crural dyssynchrony index, and regional time-to-peak dispersion with weaning outcomes; and (4) evaluating the feasibility, analyzable image rate, and repeatability of diaphragmatic speckle-tracking and RDSI calculation in patients undergoing PSV-SBT.

This study proposes the End-expiratory Diaphragmatic Residual Contraction (EDRC) index to quantify residual diaphragmatic activity at end-expiration during Pressure Support Ventilation (PSV) mode. The study aims to validate the relationship between EDRC and dynamic intrinsic PEEP (PEEPi), triggering load, patient-ventilator asynchrony, and PEEP responsiveness through a brief, standardized PEEP titration trial conducted within a clinically safe range. This will provide a basis for subsequent individualized PEEP setting guided by EDRC.

Currently, measurement of transdiaphragmatic pressure (Pdi) using oesophageal and gastric balloons is the gold standard for the assessment of diaphragmatic effort. This technique is relatively invasive and its interpretation may be complex. The diaphragmatic longitudinal strain (LSdi) and strain rate (LSRdi) might provide additional information in the assessment of diaphragmatic effort and movement during SBT, allowing early detection of diaphragmatic dysfunction. Patients will be monitored during a 30-120 minutes SBT consisting of no assistance on the ventilator using CPAP with a pressure level of 0 cmH2O. Parameters to evaluate diaphragm function will include diaphragmatic strain (LSdi and LSRdi), diaphragmatic thickening fraction (TFdi), and airway occlusion pressure (ΔP0.1 and ΔPocc). These parameters will be measured immediately before ('baseline') the SBT, as well as 2 minutes ('early' assessment), 15 ('intermediate' assessment) and 30 minutes ('late' assessment) after the beginning of the SBT.

Septic shock is a critical condition associated with high mortality. Transthoracic echocardiography is widely used to evaluate cardiac function and guide treatment. Left and right atrial strain (LAS and RAS) measured via speckle tracking echocardiography have shown prognostic value in cardiovascular diseases. However, differences exist between echocardiographic software, leading to challenges in result comparability. This study aims to compare LAS and RAS measurements between ECHOPAC and UWS software, evaluate AutoStrain technology, and assess reproducibility across observers. The study is non-interventional and will use retrospective echocardiographic data from patients treated for septic shock. The findings will contribute to improving measurement standardization in critically ill patients.