Comparison of subclavian vein to inferior vena cava collapsibility by ultrasound in acute heart failure: A pilot study

Ultrasonographic Evaluation of Hypervolemic and Normovolemic Patients: A Comparison of Inferior Vena Cava, Subclavian Vein, Internal Jugular Vein, and Femoral Vein Diameters and Collapsibility Indices

Background and objective We aimed to determine the diameters and respiratory variability of the subclavian vein (SCV), internal jugular vein (IJV), and femoral vein (FV), which are more superficial and easier to visualize with point-of-care ultrasound (PoCUS) in the detection of volume overload, and to investigate whether they can be an alternative to analyzing an inferior vena cava (IVC) to determine volume load. Methodology We prospectively evaluated volume-overloaded and normovolemic patients admitted to the emergency department using PoCUS for six months. Inspiratory-expiratory diameters and collapsibility indices (CI) of IVC and SCV, IJV, and FV were evaluated. The correlation between IVC and SCV, IJV, and FV was analyzed. Results A total of 176 patients were included in the study, including 88 volume-overloaded patients in the study group and 88 normovolemic patients in the control group. The median values of the maximum and minimum diameters of the IVC, SCV, IJV, and FV in the study group were statistically higher compared to the control group. A moderate correlation was found between IVC and SCV, IVC and IJV, and IVC and FV for maximum diameters in all patients (p = 0.447, p = 0.515, and p = 450, respectively). There was a very weak correlation between the IVC-CI and the FV-CI in all patients (p = 0.160), and no correlation was found with the other veins. Conclusion The IVC-CI was not correlated with the SCV-CI, the IJV-CI, or the FV-CI in volume-overloaded patients; therefore, superficial venous vessels cannot be an alternative to the IVC.

The Cardiac Pulsed Wave Doppler Pattern of the Common Femoral Vein in Diagnosing the Likelihood of Severe Pulmonary Hypertension: Results from a Prospective Multicentric Study

Background and Objectives: Pulmonary hypertension (PH) is a clinical condition with high mortality rates, particularly in patients over 65. Current guidelines recommend assessing the likelihood of pulmonary hypertension (LPH) using advanced echocardiography before proceeding to right heart catheterization. This study proposed using the common femoral vein (CFV), an accessible vein that reflects right atrial pressure, as an alternative method to assess the high likelihood of pulmonary hypertension (H-LPH). Materials and Methods: This prospective observational study included 175 emergency patients from three hospitals. Ultrasound assessed the pulsed wave Doppler (PW-Doppler) morphology of the CFV. This diagnostic yield for H-LPH was evaluated alongside traditional ultrasound parameters (right-to-left ventricular basal diameter ratio greater than 1 (RV > LV), septal flattening, right ventricular outflow acceleration time (RVOT) of less than 105 ms and/or mesosystolic notching, pulmonary artery diameter greater than the aortic root (AR) diameter or over 25 mm, early pulmonary regurgitation maximum velocity > 2.2 m/s; TAPSE/PASP less than 0.55, inferior vena cava (IVC) diameter over 21 mm with decreased inspiratory collapse, and right atrial (RA) area over 18 cm2). Results: The CFV's PW-Doppler cardiac pattern correlated strongly with H-LPH, showing a sensitivity (Sn) of 72% and a specificity (Sp) of 96%. RA dilation and TAPSE/PASP < 0.55 also played significant diagnostic roles. Conclusions: The CFV's PW-Doppler cardiac pattern is an effective indicator of H-LPH, allowing reliable exclusion of this condition when absent. This approach could simplify initial LPH evaluation in emergency settings or where echocardiographic resources are limited.

Inferior vena cava ultrasound and other techniques for assessment of intravascular and extravascular volume: an update

Goals of volume management are to accurately assess intravascular and extravascular volume and predict response to volume administration, vasopressor support or volume removal. Data are reviewed that support the following: (i) Dynamic parameters reliably guide volume administration and may improve clinical outcomes compared with static parameters, but some are invasive or only validated with mechanical ventilation without spontaneous breathing. (ii) Ultrasound visualization of inferior vena cava (IVC) diameter variations with respiration reliably assesses intravascular volume and predicts volume responsiveness. (iii) Although physiology of IVC respiratory variations differs with mechanical ventilation and spontaneous breathing, the IVC collapsibility index (CI) and distensibility index are interconvertible. (iv) Prediction of volume responsiveness by IVC CI is comparable for mechanical ventilation and spontaneous breathing patients. (v) Respiratory variations of subclavian/proximal axillary and internal jugular veins by ultrasound are alternative sites, with comparable reliability. (vi) Data support clinical applicability of IVC CI to predict hypotension with anesthesia, guide ultrafiltration goals, predict dry weight, predict intra-dialytic hypotension and assess acute decompensated heart failure. (vii) IVC ultrasound may complement ultrasound of heart and lungs, and abdominal organs for venous congestion, for assessing and managing volume overload and deresuscitation, renal failure and shock. (viii) IVC ultrasound has limitations including inadequate visualization. Ultrasound data should always be interpreted in clinical context. Additional studies are required to further assess and validate the role of bedside ultrasonography in clinical care.

The Role of Ultrasonographic Inferior Vena Cava Measurement in the Volume-Based Classification of Patients With Hyponatremia

OBJECTIVES

To demonstrate the role of inferior vena cava (IVC) collapsibility in the assessment of volume status in hyponatremic critically ill patients in the emergency department (ED) with bedside IVC imaging and to predict volume status with response to fluid therapy.

METHODS

A prospective 110 hypotonic hyponatremic patients aged >18 years with a serum sodium level under 125 mEq/L and at least one symptom of hyponatremia, who presented or referred to the ED was conducted. Demographical, clinical, and laboratory characteristics with bedside measurement of IVC diameter of patients were recorded. Volume status was divided into 3 subgroups: hypovolemic-G1, euvolemic-G2, and hypervolemic-G3. An ED trainee with a certification to perform basic and advanced ultrasonography (USG) training carried out the USG examinations. A diagnostic algorithm approach was made according to the results.

RESULTS

Symptom severity was significantly greater in the hypervolemic group than the other groups (P = .009 and P = .034, respectively). Systolic blood pressure (SBP) and mean arterial pressure (MAP) were significantly lower in the hypovolemic group compared with the other groups (P < .001 and P = .003, respectively). There was a significant difference between the ultrasonographically measured IVC min, IVC max, and mean IVC values across the three volume-based groups (P < .001).

CONCLUSION

Considering the diversity of physical examination (PE) findings, with the highly heterogenous nature of hyponatremia, a new measurable algorithm can be developed on the basis of contemporary hyponatremic patient management guidelines.

Point-of-care ultrasonography in nephrology comes of age

The physical exam is changing. Many have argued that the physical exam of the 21st century should include point-of-care ultrasound (POCUS). POCUS is being taught in medical schools and has been endorsed by the major professional societies of internal medicine. In this review we describe the trend toward using POCUS in medicine and describe where the practicing nephrologist fits in. We discuss what a nephrologist's POCUS exam should entail and we give special attention to what nephrologists can gain from learning POCUS. We suggest a 'nephro-centric' approach that includes not only ultrasound of the kidney and bladder, but of the heart, lungs and vascular access. We conclude by reviewing some of the sparse data available to guide training initiatives and give suggested next steps for advancing POCUS in nephrology.