Point-of-care ultrasound (POCUS) has increasingly become an integral part of clinical practice, particularly in nephrology, where its use extends beyond renal assessment to include multi-organ evaluations. Despite challenges such as limited ultrasound training and equipment access, especially in low- and middle-income countries, the adoption of POCUS is steadily rising. This narrative review explores the growing role of multi-organ POCUS in nephrology, with applications ranging from the assessment of congestion phenotypes, cardiorenal syndrome, and hemodynamic acute kidney injury (AKI) to the evaluation of arteriovenous fistulas and electrolyte disorders. In nephrology, POCUS enhances clinical decision making by enabling rapid, bedside evaluations of fluid status, cardiac function, and arteriovenous access. Studies have demonstrated its utility in diagnosing and managing complications such as heart failure, cirrhosis, and volume overload in end-stage renal disease. Additionally, POCUS has proven valuable in assessing hemodynamic alterations that contribute to AKI, particularly in patients with heart failure, cirrhosis, and systemic congestion. This review highlights how integrating ultrasound techniques, including lung ultrasound, venous Doppler, and focused cardiac ultrasound, can guide fluid management and improve patient outcomes. With advancements in ultrasound technology, particularly affordable handheld devices, and the expansion of targeted training programs, the potential for POCUS to become a global standard tool in nephrology continues to grow, enabling improved care in diverse clinical settings.

Accurate assessment of a patient's volume status is crucial in many conditions, informing decisions on fluid prescribing, vasoactive agents, and decongestive therapies. Determining a patient's volume status is challenging because of limitations in examination and investigations and the complexities of fluid homeostasis in disease states. Point-of-care ultrasound (POCUS) is useful in assessing hemodynamic parameters related to volume status, fluid responsiveness, and fluid tolerance. It requires understanding several physiologic concepts to interpret and integrate POCUS findings accurately into volume-related clinical decision-making.

The following concepts serve as a scaffold for a comprehensive volume status assessment: central venous pressure, right-sided heart function, left-sided heart assessment, extravascular volume, and venous congestion. POCUS allows us access to these hemodynamic and structural data points as an extension and refinement of the physical examination. Often, multiple POCUS applications are used, and findings must be integrated with the rest of the clinical evaluation. We illustrate this using 3 common scenarios: hypotension, hypoxia, and acute kidney injury. Clinicians must be aware of the strengths and weaknesses of findings in different physiologic states and the potential pitfalls of image acquisition and interpretation. Further studies are necessary to determine the benefits and clinical outcomes of a POCUS-directed volume status assessment.

Volume status assessment is ubiquitous, yet is challenging to perform. This review summarizes foundational physiologic concepts relevant to volume status evaluation and highlights how multiorgan POCUS elucidates hemodynamic parameters that can be combined with the conventional clinical assessment to make fluid-related decisions.

An accurate assessment of intracardiac pressure and etiology of its pathologic change is crucial in assessing volume status and cardiac hemodynamics. The assessment for abnormal central venous pressure in heart failure has driven the development of noninvasive assessment of the central veins: the inferior vena cava and, more recently, ultrasound assessment of the jugular venous pressure. This article discusses the evidence, techniques, and limitations of estimating central venous pressure by ultrasound assessment of the inferior vena cava and internal jugular vein.

Ultrasound can overcome barriers to visualizing the internal jugular vein, allowing hepato-jugular reflux and jugular venous pressure measurement. We aimed to determine operating characteristics of the ultrasound hepato-jugular reflux and ultrasound jugular venous pressure predicting right atrial and pulmonary capillary occlusion pressures.

In a prospective observational cohort at three US academic hospitals the hepato-jugular reflux and jugular venous pressure were measured with ultrasound before right heart catheterization. Receiver operating curves, likelihood ratios, and regression models were utilized to compare the ultrasound hepato-jugular reflux and ultrasound jugular venous pressure to the right atrial and pulmonary capillary occlusion pressures.

In 99 adults undergoing right heart catheterization, an ultrasound hepato-jugular reflux had a negative likelihood ratio of 0.4 if 0 cm and a positive likelihood ratio of 4.3 if ≥ 1.5 cm for predicting a pulmonary capillary occlusion pressure ≥ 15 mmHg. Regression modeling predicting pulmonary capillary occlusion pressure was not only improved by including the ultrasound hepato-jugular reflux (P < .001), it was the more impactful predictor compared with the ultrasound jugular venous pressure (adjusted odds ratio 2.6 vs 1.2). The ultrasound hepato-jugular reflux showed substantial agreement (kappa 0.76; 95% confidence interval, 0.30-1.21), with poor agreement for the ultrasound jugular venous pressure (kappa 0.11; 95% confidence interval, -0.37-0.58).

In patients undergoing right heart catheterization, the ultrasound hepato-jugular reflux is reproducible, has modest impact on the probability of a normal pulmonary capillary occlusion pressure when 0 cm, and more substantial impact on the probability of an elevated pulmonary capillary occlusion pressure when ≥ 1.5 cm.

Point-of-care ultrasound (POCUS) of the internal jugular vein (IJV) offers a non-invasive means of estimating right atrial pressure (RAP), especially in cases where the inferior vena cava is inaccessible or unreliable due to conditions such as liver disease or abdominal surgery. While many clinicians are familiar with visually assessing jugular venous pressure through the internal jugular vein, this method lacks sensitivity. The utilization of POCUS significantly enhances the visualization of the vein, leading to a more accurate identification. It has been demonstrated that combining IJV POCUS with physical examination enhances the specificity of RAP estimation. This review aims to provide a comprehensive summary of the various sonographic techniques available for estimating RAP from the internal jugular vein, drawing upon existing data.

The goal of this investigation is to evaluate the accuracy of handheld ultrasound score in assessing right atrial (RA) pressure in patients with obesity with heart failure. We prospectively studied 123 patients with heart failure referred for right-sided cardiac catheterization. Handheld ultrasound was performed before catheterization to evaluate volume status by estimating RA pressure using end-expiratory inferior vena cava (IVC) dimension, IVC respiratory collapsibility, and right internal jugular (RIJ) vein respiratory collapsibility. A 3-point simple score was created using multiple logistic regression. The patients were divided into 2 groups based on body mass index. The performance of this score was assessed using the receiver operating characteristics curve in each subgroup and was compared with the performance of the 2-point score (expiratory IVC dimension, IVC respiratory collapsibility). Median age was 58 years (interquartile range 48 to 65), and 37% were women. The 3-point score including RIJ performed better than did the 2-point score in patients with obesity (area under the curve 0.84 [0.74 to 0.95] vs 0.69 [0.58 to 0.81], p = 0.001). The performance of the scores did not differ in patients without obesity (area under the curve 0.85 [0.74 to 0.95] vs 0.82 [0.71 to 0.93], p = 0.49). In patients with obesity, the 3-point score had a specificity of 100% and sensitivity of 21% (11% to 31%) for elevated RA pressure ≥10 mm Hg. In conclusion, a 3-point score including both RIJ and IVC assessment performed better in patients with obesity with heart failure and highlights the importance of comprehensive evaluation in patients with obesity to achieve an accurate, noninvasive assessment of volume status.

Current noninvasive estimation of right atrial pressure (RAP) by inferior vena cava (IVC) measurement during echocardiography may have significant inter-rater variability due to different levels of observers' experience. Therefore, there is a need to develop new approaches to decrease the variability of IVC analysis and RAP estimation. This study aims to develop a fully automated artificial intelligence (AI)-based system for automated IVC analysis and RAP estimation. We presented a multi-stage AI system to identify the IVC view, select good quality images, delineate the IVC region and quantify its thickness, enabling temporal tracking of its diameter and collapsibility changes. The automated system was trained and tested on expert manual IVC and RAP reference measurements obtained from 255 patients during routine clinical workflow. The performance was evaluated using Pearson correlation and Bland-Altman analysis for IVC values, as well as macro accuracy and chi-square test for RAP values. Our results show an excellent agreement (r=0.96) between automatically computed versus manually measured IVC values, and Bland-Altman analysis showed a small bias of [Formula: see text]0.33 mm. Further, there is an excellent agreement ([Formula: see text]) between automatically estimated versus manually derived RAP values with a macro accuracy of 0.85. The proposed AI-based system accurately quantified IVC diameter, collapsibility index, both are used for RAP estimation. This automated system could serve as a paradigm to perform IVC analysis in routine echocardiography and support various cardiac diagnostic applications.