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Inferior Vena Cava Measurement with Ultrasound: What Is the Best View and Best Mode?

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Intravascular volume status is an important clinical consideration in the management of the critically ill. Point-of-care ultrasonography (POCUS) has gained popularity as a non-invasive means of intravascular volume assessment via examination of the inferior vena cava (IVC). However, there are limited data comparing different acquisition techniques for IVC measurement by POCUS. The goal of this evaluation was to determine the reliability of three IVC acquisition techniques for volume assessment: sub-xiphoid transabdominal long axis (LA), transabdominal short axis (SA), and right lateral transabdominal coronal long axis (CLA) (aka “rescue view”).

Methods: Volunteers were evaluated by three experienced emergency physician sonographers (EP). Gray scale (B-mode) and motion-mode (M-mode) diameters were measured and IVC collapsibility index (IVCCI) calculated for three anatomic views (LA, SA, CLA). For each IVC measurement, we calculated descriptive statistics, intra-class correlation coefficients (ICC), and two-way univariate analyses of variance.

Results: EPs evaluated 39 volunteers, yielding 351 total US measurements. Measurements of the three views had similar means (LA 1.9 ± 0.4cm; SA 1.9 ± 0.4cm; CLA 2.0 ± 0.5cm). For B-Mode, LA had the highest ICC (0.86, 95% CI [0.76–0.92]) while CLA had the poorest ICC (0.74, 95% CI [0.56–0.85]). ICCs for all M-mode IVCCI were low. Significant interaction effects between anatomical view and EP were observed for B-mode and M-mode measurements. Post-hoc analyses revealed difficulty in consistent view acquisition between EPs.

Conclusion: Inter-rater reliability of the IVC by EPs was highest for B-mode LA and poorest for all M-Mode IVC collapsibility indices (IVCCI). These results suggest that B-mode LA holds the most promise to deliver reliable measures of IVC diameter. Future studies may focus on validation in a clinical setting as well as comparison to a reference standard.

No MeSH data available.


Related in: MedlinePlus

Sub-xyphoid transabdominal long axis (LA) in B-mode (top) and M-mode with respiratory variation (bottom). A: passive respiration, B: inspiratory effort.IVC, inferior vena cava
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f1-wjem-18-496: Sub-xyphoid transabdominal long axis (LA) in B-mode (top) and M-mode with respiratory variation (bottom). A: passive respiration, B: inspiratory effort.IVC, inferior vena cava

Mentions: Three anatomic approaches were used for data collection and comparison: 1) sub-xyphoid transabdominal long axis (LA) 2–3cm caudal to the right atrial (RA) junction (Figure 1); 2) transabdominal short axis (SA) immediately inferior to the inflow of the hepatic veins (Figure 2); and 3) right lateral transabdominal coronal long axis (CLA) (aka “rescue view”) 2–3cm caudal to the RA junction (Figure 3).


Inferior Vena Cava Measurement with Ultrasound: What Is the Best View and Best Mode?
Sub-xyphoid transabdominal long axis (LA) in B-mode (top) and M-mode with respiratory variation (bottom). A: passive respiration, B: inspiratory effort.IVC, inferior vena cava
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5391901&req=5

f1-wjem-18-496: Sub-xyphoid transabdominal long axis (LA) in B-mode (top) and M-mode with respiratory variation (bottom). A: passive respiration, B: inspiratory effort.IVC, inferior vena cava
Mentions: Three anatomic approaches were used for data collection and comparison: 1) sub-xyphoid transabdominal long axis (LA) 2–3cm caudal to the right atrial (RA) junction (Figure 1); 2) transabdominal short axis (SA) immediately inferior to the inflow of the hepatic veins (Figure 2); and 3) right lateral transabdominal coronal long axis (CLA) (aka “rescue view”) 2–3cm caudal to the RA junction (Figure 3).

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Intravascular volume status is an important clinical consideration in the management of the critically ill. Point-of-care ultrasonography (POCUS) has gained popularity as a non-invasive means of intravascular volume assessment via examination of the inferior vena cava (IVC). However, there are limited data comparing different acquisition techniques for IVC measurement by POCUS. The goal of this evaluation was to determine the reliability of three IVC acquisition techniques for volume assessment: sub-xiphoid transabdominal long axis (LA), transabdominal short axis (SA), and right lateral transabdominal coronal long axis (CLA) (aka “rescue view”).

Methods: Volunteers were evaluated by three experienced emergency physician sonographers (EP). Gray scale (B-mode) and motion-mode (M-mode) diameters were measured and IVC collapsibility index (IVCCI) calculated for three anatomic views (LA, SA, CLA). For each IVC measurement, we calculated descriptive statistics, intra-class correlation coefficients (ICC), and two-way univariate analyses of variance.

Results: EPs evaluated 39 volunteers, yielding 351 total US measurements. Measurements of the three views had similar means (LA 1.9 ± 0.4cm; SA 1.9 ± 0.4cm; CLA 2.0 ± 0.5cm). For B-Mode, LA had the highest ICC (0.86, 95% CI [0.76–0.92]) while CLA had the poorest ICC (0.74, 95% CI [0.56–0.85]). ICCs for all M-mode IVCCI were low. Significant interaction effects between anatomical view and EP were observed for B-mode and M-mode measurements. Post-hoc analyses revealed difficulty in consistent view acquisition between EPs.

Conclusion: Inter-rater reliability of the IVC by EPs was highest for B-mode LA and poorest for all M-Mode IVC collapsibility indices (IVCCI). These results suggest that B-mode LA holds the most promise to deliver reliable measures of IVC diameter. Future studies may focus on validation in a clinical setting as well as comparison to a reference standard.

No MeSH data available.


Related in: MedlinePlus