Abstract
BACKGROUND: Ultrasound (US) assessment of the internal jugular vein (IJV) to measure ultrasound jugular venous pressure (uJVP) has been proposed as a promising non-invasive tool for evaluating hydration status. However, a standardized method for uJVP measurement is currently lacking. METHODS: This cross-sectional study compared 4 previously described IJV-US methods in healthy, euvolemic volunteers. Methods 1 and 2 use transverse view, measuring uJVP where IJV is (1)smaller than common carotid artery or (2)collapsed throughout the respiratory cycle. Methods 3a/b use longitudinal view, measuring at the tip(3a) or base(3b) of the IJV tapering portion. US assessment was conducted by 2 independent, blinded investigators at individualized head-of-bed elevation angle according to standardized procedures. Endpoints were: a)percentage of participants with measurements differing >1 standard deviation(SD) from the previously described mean (6.5 ± 1.5 cmH₂O) for euvolemic patients, b)reproducibility and c)feasibility. RESULTS: 30 participants(50% females) were included. Median uJVP(IQR) was 3.8 cmH₂O(3.0-4.0), 4.5 cmH₂O(3.8-5.3), 3.9 cmH₂O(3.3-4.5), and 3.3 cmH₂O(2.8-3.5) for methods 1-3b. uJVP differed >1SD in 17/30(56.7%), 3/14(21.4%), 14/29(51.7%) and 25/30available assessment pairs(83.3%), respectively. Reproducibility for methods 1-3b was 18/30(60.0%), 7/30(23.3%), 19/30(63.3%) and 25/30 participants(83.3%). Assessment was feasible in 30/30 participants(100%) for methods 1 and 3b, 29/30(97%) for method 3a and 14/30(47%) for method 2. CONCLUSION: The longitudinal method measuring uJVP at the base of tapering portion showed the highest reproducibility and feasibility. Overall, measured uJVP values were consistently within the upper threshold for normal central venous pressure, but lower than the previously described values, supporting the use of uJVP for detecting hypervolemia, but not hypovolemia.