Inferior Vena Cava Diameter and Collapsibility Index measurements by Ultrasound and its Correlation with Central Venous Pressure in Critically Ill Patients

Background: The diagnosis and treatment of critically sick patients depend on an accurate evaluation of intravascular volume status. An intrusive tool utilized for this is central venous pressure (CVP). Aim of the study: In the present investigation, intravascular volume status of severely ill patients was evaluated using noninvasive Inferior Vena Cava (IVC) diameter and Collapsibility Index (CI) measurements in ICU patients and its link with CVP. Methods: A total of 100 adult patients hospitalized to the medical ICU were included in this study. CVP was measured by an intrathoracic venous catheter in the right atrium. The inferior vena cava collapsibility index (IVC-CI) was calculated by measurement of IVC diameter in expiration and inspiration by bedside ultrasound. Results: The IVC dmin and IVC dmax decreased in hypovolemic patients compared to euvolemic and hypervolemic patients. While IVC-CI showed a significant increase in hypovolemic patients. CVP showed a significant positive correlation with IVC diameter with expiration and inspiration but had a negative correlation with the IVC-CI. Conclusion: IVC diameters and collapsibility index have a significant correlation with CVP. Its measurements by ultrasound are simple, noninvasive, safe methods for evaluation of volume status versus CVP in critical patients.