292 A Cross-Sectional Study on the Correlation and Validity of Inferior Vena Cava and Internal Jugular Vein Ultrasound Measurements in Predicting Central Venous Pressure in Spontaneous Breathing Patients

Abstract

To test the correlation of central venous pressure (CVP) with inferior vena cava ( IVC) and internal jugular vein ( IJV) maximal diameters, collapsibility index, IJV ratio in a population of spontaneous breathing patients (SBP). To evaluate the validity in predicting low CVP (< 8 mmHg) of the previous ultrasound measures. This is a cross-sectional study conducted during 2015 in an Italian intensive care unit. We included adult patients with a central venous catheter without cerebral ischemia or bradycardia. Ultrasound images of IJV and IVC diameters at end-expiration (IJVDmax, IVCDmax) and at end-inspiration (IJVDmin, IVCDmin) were obtained with the patient supine using a 5-10 MHz and a 1-5 MHz probe (General Electric). At the same time, we performed a transthoracic echocardiography to evaluate the left ventricular ejection fraction and the Tricuspid annular plane systolic excursion (TAPSE) as index of Right Ventricular ejection fraction; we calculated the collapsibility index of IVC (IVCDmax - IVCDmin/IVCDmax X 100%); the anteroposterior and transverse internal jugular vein diameters at end-expiration (AP-IJV, T-IJV) and the IJV ratio (AP-IJV divided by T-IJV); we collected clinical data (with intra-abdominal pressure and CVP). Analyses were performed using the Stata/SE Statistical Software 13.1. The Mann-Whitney test was used to compare variables between patient groups. Correlations were calculated by means of Pearson or Spearman’s rank correlation coefficients. Forty-three spontaneous breathing patients were included. The overall median age was 79 years (range 64-81), SAPS II was 34 (29-46); shock was main admission diagnosis. There were significant differences (p 8mmHg regarding IVCDmax, AP-IJV, IJV ratio ( 1,8 cm vs 2,2 cm; 6,8 mm vs 9,1mm; 0,55 vs 0,67 respectively). We found a significant positive correlation between IVCDmax and IJV ratio and CVP: r=0,35, P = 0,02 and r=0,35, P = 0,03 respectively. The antroposterior IJV diameter was correlated to CVP: r=0,58, P = 0,0001. The area under the receiver operating characteristics curve to discriminate a low CVP (<8mmHG) was 0,62 95% CI 0,45-0,77) for the collapsibility index; 0,79 (95% CI 0,63-0,91) for the AP-IJV; 0,66 (95% CI 0,49-0,80) for the IVCDmax; 0,68 (95% 0,51-0,82) for the IJV ratio. If our results on the correlation of IVCDmax, IJV ratio and AP-IJV with CVP in spontaneous breathing patients will be confirmed in future studies, these measures could be used as alternative of CVP. The anteroposterior internal jugular vein maximal diameter and the IJV ratio seem to predict low CVP better than the collapsibility index of inferior vena cava and the inferior vena cava maximal diameter.