Impact of individual characteristics on sonographic IVC diameter and the IVC diameter/aorta diameter index.

BACKGROUND The inferior vena cava (IVC) parameters, including its diameter and collapsibility index have been evaluated for fluid status for over 30 years, but little is known about the impacts of patient characteristics on IVC parameters. The purpose of this study was to explore the relationships between individual patient characteristics and IVC parameters in healthy Chinese adult volunteers. METHODS From February 2012 to May 2012, 216 healthy volunteers older than the age of 18 years were consecutively enrolled in our study. The individual characteristics and presence or absence of hypertension of each participant were recorded. Sonographic measurements of IVC and abdominal aorta diameter (Ao) were performed (DP-6900; Mindray, Shenzhen, China). RESULTS Volunteers ranged in age from 18 to 84 years (43.7 ± 7.8 years), and 50.5% were males. In univariate analyses, maximum IVC diameter (IVCmax) was negatively correlated with age (years) (r = -0.171, P = .012) and positively correlated with sex (men) (r = 0.174, P = .01), height (centimeters) (r = 0.281, P < .001), and body surface area (square meters) (r = 0.173, P = .011). The IVC/Ao index was negatively correlated with age (years) (r = -0.326, P < .001), waist circumference (centimeters) (r = -0.176, P = .01), body mass index (r = -0.173, P = .011), and hypertension (r = -0.186, P = .006). None of the patient characteristics were significantly correlated with percentage collapse of the IVC. Height (centimeters) was the sole significant predictor of IVCmax (R(2) = 0.079, P < .001). Age (years) and body mass index (kilogram/square meter) were independent predictors of the IVC/Ao index (R(2) = 0.123; P < .001 and P = .046, respectively). CONCLUSIONS The percentage collapse of IVC and the IVCmax are not substantially influenced by patient characteristics. In contrast, the IVC/Ao index is more susceptible to patient characteristics than IVC.