Right Ventricular Clearance Index (RVCI): A Simple New Parameter To Assess The Right Ventricular Systolic Function Using Contrast Echocardiography In Critically Ill Patients

Patients undergo both transthoracic and transesophageal echocardiography performed by an experienced operator. The approximate duration of examination is 30 minutes. Both the transthoracic and transesophageal echocardiography are undertaken only one occasion. During transthoracic echocardiography, we measure TAPSE (tricuspid annular plane systolic excurtion), S' (tricuspid annular plane systolic peak velocity), and PASP (pulmonary artery systolic pressure). During the transesophageal echocardiography, we perform a contrast test by injecting 5 ml of ultrasound contrast agent as a bolus through the central venous catheter. The time taken by the contrast agent to totally disappear from the right ventricular is called T and is noted in seconds. The right ventricular clearance index (RVCI) is defined as follows: RVCI= (T/HR)*100 (HR = heart rate). The right atrial pressure (RAP) is measured using the central venous catheter. We will test correlations between RVCI, TAPSE and S'. We will also test correlations between RVCI, PASP and RAP We will study the ability of RVCI to detect right ventricular systolic dysfunction defined with TAPSE<16mm or S'<10cm/s