Bedside assessment of central venous pressure by sonographic measurement of right ventricular outflow-tract fractional shortening

Abstract

We aimed to assess the suitability of right ventricular outflow tract (RVOT) fractional shortening for estimating low central venous pressure (CVP). To the best of our knowledge, there have been no similar studies in the English language literature. In this cross-sectional study, the emergency physicians measured the RVOT fractional shortening on parasternal short-axis view. A receiver operating characteristic curve analysis was conducted to identify the threshold that maximized the sensitivity and specificity for discriminating normal and low CVPs by the RVOT fractional shortening value. The sensitivity, specificity, and the positive and the negative likelihood ratios of RVOT fractional shortening to truly estimate CVP were calculated. Fifty-eight consecutive patients had invasive CVP monitoring. Nine patients with high CVP and eight for other reasons were excluded. Forty-one patients were enrolled in the study, of whom 21 were in low CVP group and 20 were in normal CVP group. RVOT diastolic diameters, RVOT systolic diameters, and RVOT fractional shortening were lower in low CVP group and this difference was statistically significant (P<0.001). The cutoff value for RVOT fractional shortening to differentiate the low and normal CVPs using the highest sensitivity and specificity was 26.44%. Area under the receiver operating characteristic curve was 0.933 (0.810-0.987) with a P value of less than 0.001. The sensitivity and specificity of RVOT fractional shortening to truly estimate CVP were 95 (75-99) and 80% (58-94), respectively. In the hands of emergency physicians, a RVOT fractional shortening measurement is a good predictor of low CVP.