Ultrasound Evaluation of the Jugular Venous Pulse (US-JVP) (US-JVP)

Validation of a Novel Non-invasive Technique Based on Real-time Ultrasound B-mode to Assess the Jugular Venous Pulse

The jugular venous pulse (JVP) reflects changes in the right atrial pressure and its evaluation can be useful in managing many emergency conditions for guiding the fluid administration as well as in the diagnosis and/or prognosis of many heart and lung diseases. The present study aims: i) To validate a novel ultrasonographic (US) technique for obtaining the JVP from a high-resolution B-mode sonograms sequence, recording the changes of the cross-sectional area (CSA) of the internal jugular veins (IJV) over the cardiac cycle; ii) To develop physical and mathematical models capable of providing an indirect estimate of central venous pressure (CVP) from the changes in IJV-CSA acquired through the US investigation, and iii) To test the transferability of the novel US-JVP technique in a clinical setting.

The study will be articulated in different phases, encompassing data collection, development of physical and mathematical models, statistical evaluations, and software implementation. The clinical experimental phase of the study (data collection) will involve hospitalized adult patients requiring a scheduled central venous catheterization and measurement of the CVP as part of their usual care. The latter will be used as the gold standard measure of CVP for the subsequent data processing and analysis. A small sample of healthy adult volunteers will also be recruited only for the non-invasive US evaluation of the JVP. The validation processes will include assessment of the diagnostic power of the US-JVP estimated CVP values and US-JVP waveforms, including evaluation of sensibility, specificity, predictive positive and negative values, accuracy and precision.

Hospitalised adult patients, requiring a scheduled central venous catheterisation and measurement of the central venous pressure as part of their usual care, will undergo a non-invasive ultrasound scan of the internal jugular veins (both side of the neck) synchronized with an ECG trace, to assess the jugular venous pulse. This procedure will be performed once throughout the study.

Participants, lying at their hospital bed, will maintain their head in a fixed position on the longitudinal axis, while an operator gently places a linear probe L12-RS (7.5-11 MHz), smeared with gel, on one side of the neck, at the middle level. A 15-sec video clip of the ultrasound images will be recorded. This procedure will be repeated on the other side of the neck. In addition, three electrodes will be placed on participants' chests and connected to the ultrasound system for simultaneously measuring the ECG signal.

Internal jugular vein cross sectional area variations in cm2 over a cardiac cycle obtained from a high-resolution B-mode sonograms sequence.

Inclusion criteria: Adult (age ≥18 years) hospitalized patients, spontaneous breathing, requiring a scheduled central venous catheterization and measurement of the central venous pressure as part of their usual care; Capacity to give informed consent. Exclusion criteria: Central venous catheterization via the internal jugular venous access