POCUS for Nephrologists: Basic Principles and a General Approach

Point-of-care ultrasonography in cirrhosis-related acute kidney injury: How I do it

Discerning the etiology of acute kidney injury (AKI) in cirrhotic patients remains a formidable challenge due to diverse and overlapping causes. The conventional approach of empiric albumin administration for suspected volume depletion may inadvertently lead to fluid overload. In the recent past, point-of-care ultrasonography (POCUS) has emerged as a valuable adjunct to clinical assessment, offering advantages in terms of diagnostic accuracy, rapidity, cost-effectiveness, and patient satisfaction. This review provides insights into the strategic use of POCUS in evaluating cirrhotic patients with AKI. The review distinguishes basic and advanced POCUS, emphasizing a 5-point basic POCUS protocol for efficient assessment. This protocol includes evaluations of the kidneys and urinary bladder for obstructive nephropathy, lung ultrasound for detecting extravascular lung water, inferior vena cava (IVC) ultrasound for estimating right atrial pressure, internal jugular vein ultrasound as an alternative to IVC assessment, and focused cardiac ultrasound for assessing left ventricular (LV) systolic function and identifying potential causes of a plethoric IVC. Advanced POCUS delves into additional Doppler parameters, including stroke volume and cardiac output, LV filling pressures and venous congestion assessment to diagnose or prevent iatrogenic fluid overload. POCUS, when employed judiciously, enhances the diagnostic precision in evaluating AKI in cirrhotic patients, guiding appropriate therapeutic interventions, and minimizing the risk of fluid-related complications.

Point-of-Care Ultrasound (POCUS) Training Curriculum for Pediatric Nephrology: PCRRT-ICONIC Group Recommendations

Key Points

Background

Point-of-care ultrasound (POCUS) is commonly used in adult specialties, pediatric emergency medicine, and neonatal and pediatric critical care. Specifically, in the field of pediatric nephrology, POCUS plays a valuable role in the critical inpatient and outpatient settings. However, the lack of guidelines and a standardized curriculum for POCUS in pediatric nephrology has led to substantial discrepancies in both clinical practice and training.

Methods

A multinational, multicenter survey regarding POCUS usefulness and training was sent to 225 pediatric nephrology residents, fellows, and physicians with expertise in pediatric nephrology. On the basis of the results, an ideal pediatric nephrology POCUS curriculum was formulated with a panel of experts from across the world. Eighteen experts were included, with each expert having >10 years of experience in using POCUS in adult and pediatric nephrology. A Delphi method was used to further solidify guidelines regarding the content, curriculum, and vital skills of using POCUS in pediatric nephrology.

Results

A total of 134 pediatric nephrology trainees, specialists, and faculty responded to the survey (59.6% completion rate). A total of 87.4% of respondents believe that formal POCUS training is either highly desirable or should be mandatory in pediatric nephrology fellowship programs. Identified barriers to receiving training included lack of an organized curriculum, lack of POCUS experts and pediatric intensivists, lack of ultrasound equipment, lack of financial support, and lack of dedicated time during training. An expert panel was convened, and a Delphi survey was conducted to formulate guidelines to overcome the barriers to pediatric nephrology POCUS and standardize the training process.

Conclusions

After collaborating with prominent pediatric nephrologists, global POCUS experts proposed a comprehensive POCUS training curriculum tailored specifically for pediatric nephrology trainees, with an appeal for all pediatric nephrology education programs to integrate POCUS instruction into their curricula.

Trends in Point of Care Ultrasound Familiarity Among Undergraduate Medical Clerkship Educators

OBJECTIVES

Despite growing use of point of care ultrasound (POCUS), there remains a paucity of data about familiarity with POCUS among educators who dictate curricular content in undergraduate medical education. This paper aims to longitudinally characterize the level of comfort and frequency of POCUS use among faculty involved in undergraduate clerkship education.

METHODS

A web-based cross-sectional survey assessing comfort, frequency of use, and awareness of indications for POCUS among faculty involved in Internal Medicine, Family Medicine, and Surgery undergraduate clerkship education in a single urban academic medical center in 2016 and again in 2022.

RESULTS

A total of 45 responses from 2016 and 30 responses from 2022 are included. The percentage of faculty "not comfortable" with performing POCUS decreased from 78% to 46%, although the overall change in comfort was not statistically significant. Comfort interpreting POCUS images, frequency of POCUS use, and familiarity with the clinical applications of POCUS all improved. Faculty identified multiple barriers to more frequent POCUS use.

CONCLUSIONS

Over a six-year period at one urban, academic medical center, comfort with POCUS and frequency of use have increased slightly but remain low among core faculty responsible for clerkship education. There are still large gaps in knowledge and very few faculty regularly use POCUS, which can be attributed to multiple different barriers.

On Whether Ca-125 Is the Answer for Diagnosing Overhydration, Particularly in End-Stage Kidney Disease Patients-A Systematic Review

Overhydration (OH) is a prevalent medical problem that occurs in patients with kidney failure, but a specific marker has still not been found. Patients requiring kidney replacement therapy suffer from a water imbalance, which is correlated with mortality rates in this population. Currently, clinicians employ techniques such as bioimpedance spectroscopy (BIS) and ultrasound (USG) markers of overhydration or markers of heart and kidney function, namely NT-pro-BNP, GFR, or creatinine levels. New serum markers, including but not limited to Ca-125, galectin-3 (Gal-3), adrenomedullin (AMD), and urocortin-2 (UCN-2), are presently under research and have displayed promising results. Ca-125, which is a protein mainly used in ovarian cancer diagnoses, holds great potential to become an OH marker. It is currently being investigated by cardiologists as it corresponds to the volume status in heart failure (HF) and ventricular hypertrophy, which are also associated with OH. The need to ascertain a more precise marker of overhydration is urgent mainly because physical examinations are exceptionally inaccurate. The signs and symptoms of overhydration, such as edema or a gradual increase in body mass, are not always present, notably in patients with chronic kidney disease. Metabolic disruptions and cachexia can give a false picture of the hydration status. This review paper summarizes the existing knowledge on the assessment of a patient's hydration status, focusing specifically on kidney diseases and the role of Ca-125.

A Clinician's Guide to the Implementation of Point-of-Care Ultrasound (POCUS) in the Outpatient Practice

Point-of-care ultrasound (POCUS) is a valuable clinical tool used at the patient bedside to rapidly assess a wide variety of symptoms and problems which would otherwise take hours or even days. Though it has become the standard of care in Emergency Medicine and is becoming so in hospital internal medicine, less uptake has been appreciated in the outpatient setting despite reported interest from clinicians practicing there. A number of common barriers have been cited to explain this gap in use, which usually include access to equipment, mentorship, and time. In this review we present a proposed framework for clinicians who have an interest in implementing POCUS in their outpatient practice which we hope can mitigate some of these barriers and provide a more streamlined pathway to their desired goals.

Diagnosis of cardiovascular disease in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) are at high risk of cardiovascular disease (CVD) and cardiovascular death. Identifying and monitoring cardiovascular complications and hypertension is important for managing patients with CKD or kidney failure and transplant recipients. Biomarkers of myocardial ischaemia, such as troponins and electrocardiography (ECG), have limited utility for diagnosing cardiac ischaemia in patients with advanced CKD. Dobutamine stress echocardiography, myocardial perfusion scintigraphy and dipyridamole stress testing can be used to detect coronary disease in these patients. Left ventricular hypertrophy and left ventricular dysfunction can be detected and monitored using various techniques with differing complexity and cost, including ECG, echocardiography, nuclear magnetic resonance, CT and myocardial scintigraphy. Atrial fibrillation and other major arrhythmias are common in all stages of CKD, and ambulatory heart rhythm monitoring enables precise time profiling of these disorders. Screening for cerebrovascular disease is only indicated in asymptomatic patients with autosomal dominant polycystic kidney disease. Standardized blood pressure is recommended for hypertension diagnosis and treatment monitoring and can be complemented by ambulatory blood pressure monitoring. Judicious use of these diagnostic techniques may assist clinicians in detecting the whole range of cardiovascular alterations in patients with CKD and enable timely treatment of CVD in this high-risk population.

Beyond conventional physical examination in hepatology: POCUS

Point-of-care ultrasound (POCUS) refers to the use of ultrasound imaging through pocket-sized sonographic devices at the patient's bedside, to make a diagnosis or direct a procedure and immediately answer a clinical question. Its goal is to broaden the physical examination, not to replace conventional ultrasound studies. POCUS has evolved as a complement to physical examination and has been adopted by different medical specialties, including hepatology. A narrative synthesis of the evidence on the applications of POCUS in hepatology was carried out, describing its usefulness in the diagnosis of cirrhosis of the liver, metabolic dysfunction-associated steatotic liver disease (MASLD), decompensated cirrhosis, and portal hypertension. The review also encompasses more recent applications in the hemodynamic evaluation of the critically ill patient with cirrhosis of the liver, patients with other liver diseases, as well as in the ultrasound guidance of procedures. POCUS could make up part of the daily clinical practice of gastroenterologists and hepatologists, simplifying the initial evaluation of patients and optimizing clinical management. Its accessibility, ease of use, and low adverse event profile make POCUS a useful tool for the properly trained physician in the adequate clinical setting. The aim of this review was to describe the available evidence on the usefulness of POCUS in the daily clinical practice of gastroenterologists and hepatologists.

Point-of-Care Ultrasound Use in Nephrology: A Survey of Nephrology Program Directors, Fellows, and Fellowship Graduates

Rationale & Objective

Adoption of point-of-care ultrasound (POCUS) into nephrology practice has been relatively slow. We surveyed US nephrology program directors, their fellows, and graduates from a single training program regarding current/planned POCUS training, clinical use, and barriers to training and use.

Study Design

Anonymous, online survey.

Setting & Participants

All US nephrology program directors (n=151), their fellows (academic year 2021-2022), and 89/90 graduates (1980-2021) of the Walter Reed Nephrology Program.

Analytical Approach

Descriptive.

Results

46% (69/151) of program directors and 33% (118/361) of their fellows responded. Response rate was 62% (55/89) for Walter Reed graduates. 51% of program directors offered POCUS training, most commonly bedside training in non-POCUS oriented rotations (71%), didactic lectures (68%), and simulation (43%). 46% of fellows reported receiving POCUS training, but of these, many reported not being sufficiently trained/not confident in kidney (56%), bladder (50%), and inferior vena cava assessment (46%). Common barriers to training reported by program directors were not enough trained faculty (78%), themselves not being sufficiently trained (55%), and equipment expense (51%). 64% of program directors and 55% of fellows reported <10% of faculty were able to perform POCUS. 64% of fellows reported having too little POCUS training. 72% of program directors and 77% of graduates felt POCUS should be incorporated into the fellowship curriculum. 59% of fellows and 61% of graduates desired hands-on POCUS training rather than didactic lectures or simulation.

Limitations

Loss of respondents as program directors and fellows progressed through the survey.

Conclusions

Nephrology program directors, fellows, and graduates surveyed want POCUS training incorporated into the fellowship curriculum. No group felt sufficiently trained to confidently perform POCUS, and the major barrier to training was lack of sufficiently trained faculty. This highlights the need to "train the trainers" before POCUS can be fully integrated into fellowship training and regularly used in nephrology practice.

Point of care ultrasonography in onco-nephrology: A stride toward better physical examination

Onco-Nephrology is an emerging subspecialty of Nephrology that focuses on a broad spectrum of renal disorders that can arise in patients with cancer. It encompasses acute kidney injury (AKI), complex fluid, electrolyte, and acid-base disorders, as well as chronic kidney disease caused or exacerbated by cancer and/or its treatment. In many such scenarios including AKI and hyponatremia, objective evaluation of hemodynamics is vital for appropriate management. Point of care ultrasonography (POCUS) is a limited ultrasound exam performed at the bedside and interpreted by the treating physician intended to answer focused clinical questions and guide therapy. Compared to conventional physical examination, POCUS offers substantially higher diagnostic accuracy for various structural and hemodynamic derangements. In this narrative review, we provide an overview of the utility of POCUS enhanced physical examination for the Onconephrologist supported by the current evidence and our experience-based opinion.

Nephrologist-performed point-of-care venous excess Doppler ultrasound (VExUS) in the management of acute kidney injury

Acute kidney injury (AKI) is frequently associated with alterations in fluid balance making accurate assessment of hemodynamics a vital component of patient management. Unfortunately, conventional parameters such as history, physical examination, vital signs, weight, natriuretic peptides have limitations in this regard. Point of care ultrasonography (POCUS) is a clinician-performed limited ultrasound study intended to answer focused clinical questions at the bedside. In the past several years, it has evolved as an extension of physical examination in various medical specialties. Herein, we describe a case of AKI where nephrologist-performed multi-organ POCUS aided in accurate diagnosis of fluid overload state. In addition, we describe how venous Doppler (VExUS) evaluation can be used to monitor the efficacy of decongestive therapy in real-time. Nephrologists should adopt a multi-parametric approach integrating all the pieces of hemodynamic puzzle when evaluating patients with AKI and fluid/electrolyte disorders.

Point-of-care ultrasound in pediatric nephrology

Point-of-care ultrasound (POCUS) has evolved in recent years in clinical practice, helping in early bedside diagnosis of important etiologies. Many medical schools and training programs are integrating POCUS into their curriculum. Especially with the technological advances of newer handheld ultrasound devices, POCUS has now become a component adjunct to clinical examination, in the clinic and bedside in critical care units. The diagnostic utility of POCUS lies both in early identification of critical kidney disease, and also extra-renal pathologies from a focused cardiac ultrasound, lung ultrasound, and integrated fluid assessment. There is a need to incorporate POCUS in training in pediatric nephrology and establish competency standard criteria. This review shall cover how POCUS helps in enhancing patient care in pediatric kidney disorders and critical children, and the recent advances.

PoCUS in nephrology: a new tool to improve our diagnostic skills

Point-of-Care Ultrasonography (PoCUS) aims to include a fifth pillar (insonation) in the classical physical examination in order to obtain images to answer specific questions by the clinician at the patient's bedside, allowing rapid identification of structural or functional abnormalities, enabling more accurate volume assessment and supporting diagnosis, as well as guiding procedures. In recent years, PoCUS has started becoming a valuable tool in day-to-day clinical practice, adopted by healthcare professionals from various medical specialties, never replacing physical examination but improving patient and medical care and experience. Renal patients represent a wide range of diseases, which lends PoCUS a special role as a valuable tool in different scenarios, not only for volume-related information but also for the assessment of a wide range of acute and chronic conditions, enhancing the sensitivity of conventional physical examination in nephrology. PoCUS in the hands of a nephrologist is a precision medicine tool.

Venous Excess Doppler Ultrasound for the Nephrologist: Pearls and Pitfalls

The role of venous congestion in abnormal kidney function is being increasingly recognized. It is well known that unresolved congestion is associated with adverse kidney and overall outcomes in patients with heart failure. Similarly, any condition that leads to elevated central venous pressure, such as pulmonary hypertension, can result in impaired kidney perfusion by increasing its afterload. Point-of-care ultrasonography (POCUS) enables the clinician to objectively assess hemodynamics at the bedside and, thereby, guide patient management. Lung POCUS has received widespread attention in the recent past because of the relative ease of the technique, but it reflects only left heart pressures and not venous congestion. Although inferior vena cava POCUS is used to estimate right atrial pressure, its isolated use cannot demonstrate organ congestion. Moreover, it is associated with several technical and conceptual limitations. Recently, venous excess Doppler ultrasound has emerged as a tool to assess venous congestion at the organ level in real time. Severe flow abnormalities in hepatic, portal, and kidney parenchymal veins have shown to predict the risk of congestive kidney injury. In addition, it helps to objectively monitor the efficacy of decongestive therapy. In this review, we provide a brief overview of various components of venous excess Doppler ultrasound and share our perspective on incorporating this novel tool in nephrology practice.

Multi-Organ Point-Of-Care Ultrasound in Acute Kidney Injury

Acute kidney injury (AKI) is a clinical syndrome caused by a multitude of hemodynamic, toxic, and structural insults to the kidney, and portends worse patient outcomes. Despite careful history taking, physical examination, and analysis of laboratory data, a void is evident in the diagnostic process and clinical monitoring of AKI. Point-of-care ultrasonography (POCUS) is a limited ultrasound study performed by the clinician at bedside as an adjunct to physical examination. Growing body of evidence points to POCUS as a powerful tool in a variety of clinical settings. Herein, we discuss how nephrologist-performed POCUS has the potential to provide answers to focused questions that we encounter in diagnosis and management of patients with AKI. From excluding hydronephrosis to providing real-time insights into hemodynamics, incorporation of POCUS helps integrate all the pieces of patient data and formulate individualized treatment plans. Future studies are needed to evaluate the impact of multi-organ POCUS on AKI-related pragmatic patient outcomes, the potential of this technique to stratify the risk and to identify patients with different levels of severity of AKI and different pathophysiological signatures.