Measurement of Caval Aorta Diameter Index by Transthoracic Echocardiogram in Normal Indian Population

Background: Bedside ultrasonography is a promising noninvasive and rapid technique to assess body fluid status. Early detection of hypovolemia and hypervolemia is crucial to guide management in critically ill patients. There is a considerable demographic variability in the normal range of inferior vena cava dimensions as seen in numerous studies and a steadfast formula to calculate caval diameter based on demographic parameters and body growth is not available till date. Caval aorta diameter index had a positive correlation with invasively measured central venous pressure as established by previous studies done in intensive care units. The simplicity of examination technique makes this index useful in every situation where body fluid status has therapeutic and prognostic implications. This study aims to identify standard normal measurement of caval aorta index by easily available two-dimensional echocardiography in subcostal view and by right coronal approach/transhepatic view in different age groups in Indian patients. Materials and Methods: One hundred and two patients referred for routine cardiac status evaluation who were asymptomatic and clinically normal without any major medical illness with normal echocardiogram were prospectively analyzed and caval aorta index assessed in both subxiphoid and transhepatic right coronal view. Results: Normal caval aorta index measured in subcostal view was 1.108 ± 0.076 and measured in transhepatic view was 1.101 ± 0.082 (mean ± 2 standard deviation). The difference of caval aorta index measured in both views was not significant statistically (P = 0.207). Conclusion: In this study, we provide a normal reference level for sonographic caval aorta index in Indian population measured in subxiphoid and transhepatic views. We also conclude that transhepatic right coronal view measurements for this index are comparable to subcostal view, so both views can be used alternatively when one window is suboptimal.