Using Automatic Speckle Tracking Imaging to Measure Diaphragm Excursion and Predict the Outcome of Mechanical Ventilation Weaning

Abstract

IntroductionThe speckle tracking ultrasound is an innovative technology enabling distinct assessment of diaphragmatic movement yet the relative data are scarce. In this pilot study, we sought to evaluate the predictive value for the weaning outcome of automatic speckle tracking in assessing diaphragm movement.MethodsThis prospective, multi-center, observational study. A total of 160 critically ill subjects underwent speckle tracking ultrasonography of the right/left hemidiaphragm before the spontaneous breathing trial. Meanwhile, the diaphragm excursion and velocity values were measured manually by M-mode ultrasound. Patients were divided into weaning-failure and weaning-success groups. The correlation was assessed between automatic and manual measurement and the diagnostic efficacy of automatic measured excursion and velocity for predicting weaning outcome was analyzed.Results88 patients completed the follow-up of the weaning outcome. The overall incidence of weaning failure was 43.18%. There was a strong association between automatic measurement of mean excursion and velocity assessed by speckle tracking imaging and manual measurement (R2 0.81 and 0.99, respectively). Receiver operating characteristic (ROC) curve analysis showed that the mean excursion and diaphragmatic velocity exhibited high diagnostic values for prolonged weaning (area under the ROC curve(AUROC) 0.824 and 0.786, respectively). The diaphragmatic excursion showed moderate diagnostic value for predicting both weaning failure and in-hospital death/withdrawing treatment ((AUROC 0.659 and 0.653, respectively). ConclusionAutomatic speckle tracking analysis of the diaphragm showed high consistency with conventional manual ultrasound measures. Diaphragmatic excursion and its excursion velocity helped predict mechanical ventilation weaning failure, prolonged weaning, as well as in-hospital adverse outcomes, which served as a reliable tool in guiding clinical weaning strategy.