Reliability of Alternative Sonographic Approaches for Inferior Vena Cava: Comparison of Subcostal, Transhepatic, and...

Ultrasonographic evaluation of the inferior vena cava (IVC) is widely used in critical care settings; however, the standard subcostal (SC) approach is not always feasible.

This study aimed to assess the agreement of IVC diameter and collapsibility index (cIVC) measurements obtained from the SC, anterior transhepatic (TH), and right coronal (CR) ultrasonographic windows.

In this prospective, single-center study conducted in an emergency department, IVC ultrasonography was performed on 219 adult patients using SC, TH, and CR approaches. Clear visualization of the anterior and posterior IVC walls was considered essential, while the visualization of IVC entry into the right atrium and the hepatic vein were supportive. Image acquisition time, operator-assessed ease, body mass index, and intermethod agreement were assessed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis.

The mean image acquisition times were 24.26 ± 24.77 s for SC, 28.89 ± 25.85 s for TH, and 35.66 ± 29.52 s for CR. ICC analysis demonstrated strong correlation across all methods, with the highest correlation observed between SCmin and THmin (r = 0.952). Bland-Altman plots showed acceptable limits of agreement, indicating good agreement. ICC analysis found to be positive and highly significant correlation across body mass index categories. More than half of the images obtained via each window were rated as "easy" or "very easy" by the operators.

While the SC window remains the first-line approach for IVC assessment, the TH and CR windows offer reliable and practical alternatives when SC imaging is limited.