Ultrasound-guided venous pressure measurement Current knowledge and potential future applications, an underrated method?

Current standard technique for venous pressure measurement is still invasive, requiring insertion of a catheter. Additionally, clinical estimation of central venous pressure (CVP) has proven unreliable compared to invasive methods. Meanwhile, different non-invasive ultrasound guided modalities may provide a valid alternative to invasive venous pressure measurement. Particularly promising is a novel compression ultrasound (CUS) which combines ultrasound properties with a tissue pressure manometer enabling even further future applications. This review provides an overview using ultrasound guided non-invasive venous pressure measurement (UGPni) in clinical trials so far and focuses on three objectives: (1) To summarize the main methods using UGPni for central venous pressure measurement (2) To outline the key findings of previous clinical trials for UGPni regarding CVP measurement with primary focus on novel compression ultrasound of a forearm vein (3) To point out limitations and possible future clinical implications of these ultrasound modalities UGPni represents an easy-to-perform and safe alternative to invasive "gold standard" diagnostic tools for measuring central venous pressure. After a brief introduction, non-specialist personnel using a portable ultrasound device can apply this method in a feasible way. Of all mentioned methods in this review CUS is the method of choice underscoring its ability to assess a patient's CVP categories correctly. Furthermore, detection of non-invasive central venous pressure in the emergency room represents an independent predictor for cardiac rehospitalization in patients with decompensated heart failure, thus helping in risk stratification as well as being an additive tool in general hemodynamic management of critically ill patients. This review concludes a significant role for ultrasound guided non-invasive venous pressure measurement suitable for a wide range of everyday clinical practice. However, further studies are warranted to proof a causal relationship in this regard.