The Jugular Vein Ultrasonography for Hydration Assessment in Healthy Participants

Proper hydration is crucial for health, and imbalances-like dehydration or fluid overload-can cause serious health problems including increased morbidity, hospitalization rate, and even mortality. Currently, assessing hydration is challenging, and there is no standardized method in clinical use. Ultrasound (US) of the internal jugular vein (IJV) and ultrasound-guided estimation of jugular venous pressure (uJVP) is a promising, non-invasive method to assess the hydration status. Several measure methods have been described, however, there is no univocal protocol for US IJV-assessment. In this study, three existing protocols including 4 measurements are compared to measure uJVP, which reflects the body's fluid balance. The study aims to find out which method is most accurate, easy to perform, and consistent when done by the same or different medical professionals. They will also look at how long each method takes and how acceptable these tests are to participants. The study is performed in healthy individuals and all 4 measurements are applied cross-sectional during one visit. The whole ultrasound assessment will have a duration of maximum 45 minutes. For all protocols, uJVP will be calculated by measuring with a ruler the vertical distance between IJV-height and sternal angle (cm) and then adding 5cm to this value. Protocol 1: IJV tapering portion is portrayed in a transverse view. The IJV height is marked and measured as soon as IJV is smaller than Common Carotid Artery (CCA) throughout the whole respiratory cycle. Protocol 2: IJV tapering portion is portrayed in a transverse view. The IJV height is marked and measured as soon as IJV is completely collapsed throughout the whole respiratory cycle. Protocol 3: IJV tapering portion is portrayed in a longitudinal view. The IJV height at the end of expiration is marked and measured at the following two positions: 1. Measurement 1: at the very end of the tapering portion (collapsing point / top of pulsation). 2. Measurement 2: at the beginning of the tapering portion (taper point).