Background: In this study, we aimed to investigate the effects of midazolam sedation on intravascular volume in intubated patients diagnosed with sepsis and treated with invasive mechanical ventilation in continuous positive airway pressure mode using echocardiography (ECHO) parameters. Methods and Results: One hundred fifty-two intensive care unit patients aged 30-50 years with spontaneous breathing who were intubated, ventilated in continuous positive airway pressure mode via invasive mechanical ventilation, were determined to have fluid deficit. Cardiac index, cardiac out-put and velocity time integral measurements were performed by passive leg rising test before and after midazolam sedation in hypovolemic patients that were determined to respond to fluid treatment and changes in passive leg rising test before and after midazolam were compared. >15% cardiac out-put, >10% cardiac index, and >15% velocity time integral increase in passive leg rising test before midazolam administration showed that patients were hypovolemic and responded to fluid therapy. <15% cardiac out-put, <10% cardiac index, and <15% velocity time integral increase in passive leg rising test after midazolam administration showed that patients were not hypovolemic. Conclusion: We recommend that passive leg raising test, which is performed to determine the intravascular volume status of critically ill intensive care unit patients determined to be hypovolemic and responding to fluid therapy, should be performed before midazolam sedation.