Secondary objectives of this study are:~to determine a threshold value of diaphragmatic excursion (ultrasound measures: expiration versus inspiration)that best predicts a 40% collapsibility of the inferior vena cava (IVC).~to determine a threshold value of diaphragmatic excursion (ultrasound measures: expiration versus inspiration)that best predicts a 100% collapsibility of the IVC.~to determine the location of the cutting plane for the TM analysis of collapsibility of the IVC.~to evaluate the hemodynamic conditions of normal healthy volunteers.~to detect any abnormality of cardiac function.
The main objective of this study is to determine a threshold value of diaphragmatic excursion (ultrasound measures: expiration versus inspiration)that best predicts a 50% collapsibility of the inferior vena cava.