Correlation Between Transhepatic and Subcostal Inferior Vena Cava Views to Assess Inferior Vena Cava Variation: A Pilot Study.

OBJECTIVES

To assess the feasibility and reliability of transthoracic echocardiography to measure inferior vena cava (IVC) diameter variation using a transhepatic view.

DESIGN

Prospective cohort study.

SETTING

Single-center hospital.

PATIENTS

Forty consecutive patients undergoing elective cardiac surgery.

INTERVENTIONS

Bedside transthoracic echocardiography.

MEASUREMENTS AND MAIN RESULTS

Correlation between the two views was measured using Pearson R, while agreement was measured using the intraclass correlation coefficient (ICC). In a nested sub-study of 16 randomly selected participants, all images were re-rated by the same rater, who was blinded to the original measurement results, and by a second blinded operator. Correlation between the subcostal and transhepatic views was moderate when assessing maximum (R 0.46; 95% confidence interval [CI], 0.18-0.68), and minimum (R 0.55; CI, 0.29-0.74) IVC diameter. Correlation when measuring IVC diameter variation was higher (R 0.70; CI, 0.49-0.83). Agreement between the two views for IVC diameter variation measurement was substantial (ICC 0.73; CI, 0.49-0.85). Intra-rater reliability was excellent (ICC 0.95-0.99).

CONCLUSIONS

Agreement between subcostal and transhepatic views was substantial for the assessment of IVC diameter variation; however, the magnitude of agreement was less than anticipated. Further research is needed to determine if the transhepatic view can be used reliably in the assessment of fluid responsiveness.