Inferior Vena Cava Compliance in Trans-thoracic Echocardiography: is the Trans-hepatic Window as Reliable as the Subcostal One

Transthoracic echocardiogram (TTE) is a widely used and validated imaging technique which involves the study of the heart and great vessels through multiple examination windows. In particular, the subcostal window represents the gold standard for evaluating the diameter of the inferior vena cava (IVC) and its compliance, allowing the physician to obtain valuable information on the volume status of patients. Acquiring images in the subcostal window with a transthoracic echocardiogram (TTE) can be, in some cases, difficult or impossible due to the presence of drainages or surgical wounds: in such cases an alternative could be represented by the trans-hepatic window. This has not been validated in the scientific litterature.

"The Clear Sight System is a non-invasive blood pressure (BP) monitoring system, where the CO is determined analysing the photo-plethysmography curve by a miniaturized pressure cuff and infrared LEDs.~Its main advantage is to assess CO continuously in a completely non-invasive way, following its variations and thereby contributing to the detection of hypovolaemia. Other visualized parameters are: the stroke volume (SV), the systemic vascular resistance (SVR) as well as the BP and the heart rate (HR)."