The interrater reliability of ultrasound imaging of the inferior vena cava performed by emergency residents.

OBJECTIVE: Ultrasonography (US) has gained popularity in the emergency medicine to assess intravascular volume status in critically ill patients. However, there are a limited number of studies on the interrater reliability of US examination of the inferior vena cava (IVC) by emergency residents.

METHOD: One hundred eighty US examinations were performed on 90 emergency critical care unit patients by 6 emergency medicine residents. Minimum and maximum IVC diameters during normal passive inspiration were measured, and the IVC index was calculated. The interrater reliability of the measurable data was analyzed using intraclass correlation coefficients.

RESULTS: The measurements of minimum and maximum IVC diameters were moderately reliable by emergency residents (κ = 0.60 [95% confidence interval {CI}, 0.45-0.72] and κ = 0.56 [95% CI, 0.41-0.69], respectively). In the patients with moderate IVC depth (8.5-12.5 cm), the interrater reliabilities of sonographers were κ = 0.51 (95% CI, 0.30-0.67) for maximum diameter and κ = 0.43 (95% CI, 0.21-0.61) for minimum diameter. In patients with superficial (≤8.5 cm) and profound located (≥12.5 cm) IVC, the interrater reliabilities of sonographers for maximum and minimum diameters were κ = 0.69 (95% CI, 0.29-0.89) and κ = 0.75 (95% CI, 0.4-0.91), and κ = 0.58 (95% CI, 0.09-0.85) and κ = 0.76 (95% CI, 0.39-0.92), respectively.

CONCLUSION: The measurement of the IVC is moderately reliable by emergency residents. The interrater reliability of measurements in patients with profound and superficial located IVC is higher than that of measurements in patients with moderate-depth located IVC.