Measurement of Femoral Vein Diameter by Ultrasound to Estimate Central Venous Pressure.
Ann Am Thorac Soc. 2015 Nov 12;
Authors: Cho RJ, Williams DR, Leatherman JW
Abstract
RATIONALE: Central venous pressure (CVP) can be estimated by ultrasound of the inferior vena cava (IVC), but imaging the IVC is sometimes challenging. The femoral vein is easily imaged by ultrasound and might therefore provide an alternate target for estimating CVP.
OBJECTIVE: To assess femoral vein diameter (FVD) measured by ultrasound imaging for estimating CVP.
METHODS: We prospectively measured CVP and FVD in 97 patients. Receiver operating characteristic curves (ROC) were used to assess the ability of FVD to predict specific CVP values: <10 mmHg, <8 mmHg (low CVP), and >12 mmHg (high CVP). Inter-observer variability of FVD measurement was assessed in 20 patients.
MEASUREMENTS AND MAIN RESULTS: There was moderate correlation between FVD and CVP (r=0.66, p<0.001). FVD ≤ 0.8 cm was the best predictor of CVP < 10 mmHg, with an area under the curve (AUC) of 0.894, 95%CI [0.82-0.97]. FVD ≤0.7cm performed best for predicting low CVP (AUC=0.97, 95%CI [0.94-0.99]) and FVD ≥ 1.0cm for high CVP (AUC=0.80, 95%CI [0.72-0.89]). However, FVD ≥ 1.2cm had the greatest specificity (94%) for high CVP. Inter-observer variability in FVD measurements was 8.3 ± 7.2%.
CONCLUSIONS: The results of this exploratory study suggest that the accuracy of femoral vein diameter measured by ultrasound imaging for estimating CVP is comparable to that which has been reported for ultrasound measurement of IVC diameter. FVD may provide an alternative approach when the IVC is difficult to image. Additional studies on other cohorts of patients are warranted to validate our proposed FVD cutoff values for predicting low and high CVP.
PMID: 26561731 [PubMed - as supplied by publisher]