Journal of Critical and Intensive Care Online Early
The Interrater Reliability of Inferior Vena Cava Ultrasonography Performed by Intensive Care Fellows
1Hacettepe University, Faculty of Medicine, Department of Intensive Care Unit, Ankara, Turkey
2Hacettepe University, Department of Anesthesiology and Reanimation, Ankara, Turkey
3Hacettepe University, Department of Anestesiology and Reanimation, Ankara, Turkey
4Gazi University, Department of Emergency Medicine, Ankara, Turkey
5Hacettepe University, Department of Intensive Care Medicine, Ankara, Turkey
6Hacettepe University, Department of Anesthesiology and Crit Care Medicine, Ankara, Turkey
DOI : 10.37678/dcybd.2021.2552 Background and aim: Inferior vena cava (IVC) measurements by ultrasonography (USG) is a repeatable and noninvasive tool but it is sonographer dependent and requires experience. The aim of this study is to investigate the interrater reliability of IVC-USG measurements performed by intensive care fellows.

Methods: After training, four first-year intensive care fellows and an experienced ultrasonography trainer performed IVC USG within 5 minutes of each other without the fellows knowing the clinical history, the fluid balance and the previous IVC USG measurements of the patients. The minimum IVC diameter (IVC-min) and the maximum diameter (IVC-max) were measured using both M-mode and B mode. IVC collapsibility index (IVC CI) and the IVC distensibility index (IVC-DI) were calculated. The interrater reliability of the measurements was analyzed using intraclass correlation coefficients (ICC) with 95% confidence intervals (CI).

Results: One hundred and seven IVC-USG measurements were conducted on 29 ICU patients. The trainer measured the median (minimum-maximum) IVC-min as 1.20(0.63-2.60) cm, IVC max as 1.76(0.95- 3.09) cm, and calculated IVC-CI as 0.23(0.05-0.68), and IVC-DI 0.30 (0.05-2.10) with B mode. The same measurements with M mode were as 1.34 (0.46-2.53) cm, 1.75 (1.07-3.08) cm, 0.19 (0.09-0.66), and 0.23 (0.10-1.95) respectively. All measurements of all of the fellows showed significant moderate-good correlations with the trainer’s measurements and each other (ICC > 0.6-0.8, p<0.001). One fellow’s parameters of B mode and M mode IVC collapsibility and distensibility index showed weak correlation to the trainer’s and other fellows’ parameters. Most correlations between fellows’ calculated parameters were also moderate (ICC >504- 777, p<0.001).

Conclusion: The interrater reliability of IVC diameters, IVC collapsibility and IVC distensibility measurements performed by intensive care fellows is moderate. Keywords : ultrasonography, vena cava inferior, reliability, safety, intensive care units