Purpose: To compare the bedside ultrasound estimation of internal jugular vein (IJV)-collapsibility index with inferior vena cava (IVC)-collapsibility index and invasively monitored central venous pressure (CVP) in ICU patients.
Design: prospective observational study.
Setting: The study was carried out in the ICU of Al Wakra and Al Khor hospitals of the Hamad Medical Corporation, Qatar. The patients were enrolled from November 2013 to January 2015.
Patients: Patients admitted to the ICU with central venous catheter were included.
Material and methods: The A-P diameter, cross-sectional area of the right IJV, and diameter of IVC were measured using bedside USG, and their corresponding collapsibility indices were obtained. The results of the IJV and IVC indices were compared with CVP. The sensitivity, specificity, and positive and negative predictive values were calculated to determine the diagnostic and predictive accuracy of the IJV collapsibility index in predicting the CVP.
Results: Seventy patients were enrolled, out of which 12 were excluded. The mean age was 54.34±16.61 years. The mean CVP was 9.88 mmHg (range =1-25). The correlations between CVP and IJV-CI (collapsibility index) at 0° were r=-0.484 (P=0.0001), r=-0.416 (P=0.001) for the cross-sectional area (CSA) and the diameter, respectively, and, at 30°, the most significant correlation discovered was (r=-0.583, P=0.0001) for the CSA-CI and r=-0.559 (P=0.0001) for the diameter-CI. In addition, there was a significant and negative correlation between IVC-CI and CVP (r=-0.540, P=0.0001).
Conclusion: The IJV collapsibility index, especially at 30° head end elevation, can be used as a first-line approach for the bedside non-invasive assessment of CVP/fluid status in critical patients. IVC-CI can be used either as an adjunct or in conditions where IJV assessment is not possible, such as in the case of a neck trauma/surgery.
Keywords: CI; IJV; IVC; central venous pressure; collapsibility index; inferior vena cava; internal jugular vein; point of care; ultrasound.