Prognostic Value of IVC-CI in Predicting ICU Outcomes Among Mechanically Ventilated Patients

Abstract

Background: Accurate assessment of intravascular volume status is crucial in the management of critically ill, mechanically ventilated patients. While central venous pressure (CVP) is traditionally used for this purpose, non-invasive alternatives such as the inferior vena cava collapsibility index (IVC-CI) have gained interest. To evaluate the prognostic utility of IVC-CI in identifying hypovolemia and predicting volume status among mechanically ventilated ICU patients. Methods: A cross-sectional study was conducted on 120 mechanically ventilated ICU patients. Each underwent ultrasound-based IVC diameter measurements to calculate IVC-CI. Volume status was categorized based on CVP values into hypovolemic (<5 mmHg), euvolemic (5–10 mmHg), and hypervolemic (>10 mmHg) groups. Hemodynamic parameters and IVC metrics were compared, and diagnostic performance of IVC-CI was analyzed. Results: IVC-CI was significantly higher in hypovolemic patients (0.59 ± 0.05) than in euvolemic (0.34 ± 0.09) and hypervolemic (0.21 ± 0.11) groups (p < 0.001). A strong inverse correlation was observed between CVP and IVC-CI (r = –0.659, p < 0.001). IVC-CI > 0.50 demonstrated excellent sensitivity (91.6%), specificity (75.5%), and overall diagnostic accuracy (85%) for detecting hypovolemia. Conventional hemodynamic parameters did not significantly differ across volume groups. Conclusion: IVC-CI is a reliable, non-invasive indicator of hypovolemia in ventilated ICU patients. It correlates strongly with CVP and outperforms traditional hemodynamic variables, offering a practical alternative for fluid assessment in critical care settings.