Correlation of Internal Jugular Vein and Inferior Vena Cava Collapsibility Index with Direct Central Venous Pressure Measurement in Critically-ill Patients: An Observational Study

Background and aims: Prompt assessments and quick replacement of intravascular fluid are critical steps to resuscitate hypovolemic patients. Intravascular volume assessment by direct central venous pressure (CVP) measurement is an invasive, time-consuming, and labor-intensive procedure. Nowadays, bedside ultrasound -guided volume assessment of the internal jugular vein (IJV) or inferior vena cava (IVC) is commonly employed as a proxy for direct CVP. Therefore, we examined the strength of association between CVP and collapsibility index (CI) of the IJV and IVC for evaluating the volume status of critically ill patients. Methods: Bedside USG -guided A-P diameter and cross-sectional area of the right IJV and IVC were measured, and their corresponding collapsibility indices were deduced. The results of the IJV and IVC indices were correlated with CVP. Results: About 60 out of 70 enrolled patients were analyzed. The baseline clinical parameters of patients are shown in Table 1. For CSA and AP diameter, the correlations between CVP and IJV-CI at 0 degrees were r = -0.107 ( p = 0.001) and r = -0.092 ( p = 0.001). Correlations between CVP and IJV-CI at 30 degrees for CSA and diameter, however, were ( r = -0.109, p = 0.001) and ( r = -0.117, p = 0.001), respectively. Table 2 depicts the correlation between CVP and IVC-CI r = -0.503, p = 0.001 for CSA and r = -0.452, p = 0.001 for diameter. Conclusion: The IVC and IJV collapsibility indices can be used in place of invasive CVP monitoring to assess fluid status in critically ill patients.