About

Nathaniel C. Reisinger, MD, is an Adjunct Assistant Professor of Medicine in the Department of Medicine at the University of Pennsylvania's Perelman School of Medicine. His primary focus is on nephrology, with a particular emphasis on point-of-care ultrasound in nephrology, including its training, application, and management of acute kidney injury. Dr. Reisinger has contributed to the development of ultrasound training curricula and has been involved in research exploring the effectiveness of ultrasound techniques in nephrology practice. His work includes investigating pulmonary congestion diagnosis via lung ultrasound and venous excess Doppler ultrasound in the management of kidney injury. He holds a BS/BA in Biology and Chemistry from the University of Houston and completed his MD at the University of Texas Southwestern Medical School. His research and clinical interests are centered on advancing ultrasound applications to improve patient care in nephrology.

Research topics

• Medicine
• Internal medicine
• Intensive care medicine
• Radiology
• Cardiology

Selected publications

• Advancing Nephrology Education with POCUS: Key Insights From the American Society of Nephrology Kidney Week 2024 Precourse

  Kidney International Reports · 2025-03-28

  editorialOpen accessSenior author
  PublisherDOI

• Hypertensive Crisis Secondary to Afferent Baroreceptor Failure following Head and Neck Radiation

  Journal of the American Society of Nephrology · 2024-10-01

  article

  Introduction: Afferent baroreceptor failure is an uncommon cause of hypertension (HTN) that may result from carotid sinus injury. Characterized by labile HTN, postural blood pressure (BP) variation, orthostatic hypotension, and hypertensive crises, afferent baroreceptor failure is typically irreversible and often severely debilitating. Case Description: A 67-year-old woman with labile HTN, hypothyroidism, and oral squamous cell carcinoma treated with hemiglossectomy and high dose radiation to the head and neck in 2009 presented to our hospital with headaches, BP of 230/120, and stage 1 acute kidney injury. She reported paroxysms of headache, visual blurriness, nausea, and lightheadedness since at least 2015. Inpatient BP values ranged from 90/60 to 190/100, including orthostatic hypotension, supine HTN, and wide variations with use of short acting intravenous medications. Daily home medications included amlodipine 10 mg, hydrochlorothiazide (HCTZ) 25 mg, valsartan 320 mg, and pramipexole for restless leg syndrome, which was stopped. Renin activity was 0.8 ng/mL/h and aldosterone concentration was 6.1 ng/dL. CT angiography showed right renal artery stenosis estimated at 70%. Echocardiography demonstrated mild concentric hypertrophy. Amlodipine was continued, HCTZ was stopped, valsartan was reintroduced at a lower dose, and a clonidine patch was started. Serum creatinine returned to her baseline. Lower extremity compression stockings and an abdominal binder were applied and postural maneuver training was performed with physical therapy. BP logs demonstrated markedly fewer BP fluctuations and attenuation of BP extremes; the patient reported a reduction in paroxysmal symptoms ascribed to BP extremes. Discussion: Afferent baroreceptor failure from injury to carotid sinus neural structures may result in failure of counterregulatory signals during conditions that provoke extremes of blood pressure. Labile blood pressure, including paroxysms of HTN and symptomatic hypotension, can result in iterative end organ injury and disabling symptoms. Wider BP ranges are tolerated and avoidance of BP extremes is prioritized. Long-acting, central acting sympathetic blocking agents are often beneficial along with postural maneuver training, compressions stockings, and abdominal binders.

  PublisherDOI

• Effectiveness of a Brief Point of Care Ultrasound Course at a National Nephrology Conference

  POCUS Journal · 2024-04-22 · 3 citations

  articleOpen accessSenior author

  The rising demand for point of care ultrasound (POCUS) instruction during nephrology fellowship has been limited due to a shortage of trained faculty and courses designed specifically for nephrologists. A hands-on POCUS pre-course was organized during the April 2023 National Kidney Foundation (NKF) Spring Clinical Meeting to address this challenge. The course consisted of pre-recorded lectures and a 4-hour hands-on workshop guided by multidisciplinary POCUS experts. The anonymous post-course survey received responses from 25 out of 39 participants, yielding a 64.1% response rate. On a scale of 0-10, confidence levels for acquiring kidney images rose from 2.6 + 2.3 (mean + SD) pre-workshop to 7.8 + 1.5 post-workshop (p<0.001). Similarly, a remarkable improvement in confidence for acquiring lung and cardiac images was seen as scores increased from 1.8 + 2.4 to 7.7 + 1.5 (p<0.001) and from 1.5 + 2.2 to 7.2 + 1.3 (p<0.001), respectively. Additionally, respondents reported a substantial improvement in their confidence to interpret kidney, lung, and cardiac POCUS images, with scores increasing from 4.5 + 2.2 to 7.7 + 1.1 (p<0.001), 2.3 + 2.4 to 7.6 + 1.5 (p<0.001), and 2 + 2 to 7.3 + 1.5 (p<0.001), respectively. Barriers to implementing POCUS use at institutions included a perceived lack of trained faculty, limited protected time for faculty, and insufficient support from division leadership. The NKF POCUS pre-course successfully improved participants' confidence in acquiring and interpreting basic POCUS images.

  PublisherOA PDFDOI

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

  Kidney360 · 2024-03-13 · 7 citations

  articleOpen access

  Key Points Despite a high need and interest in point-of-care ultrasound (POCUS) in trainees and faculty of Pediatric Nephrology, the majority are not receiving POCUS training. There is a need to establish a structured pediatric nephrology POCUS program for clinicians and fellows. This study suggests a blueprint of POCUS curriculum which can serve as a foundation for POCUS education in pediatric nephrology centers worldwide. 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 &gt;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.

  PublisherDOI

• Incidental Finding of Retroperitoneal Lipomatosis

  Journal of the American Society of Nephrology · 2024-10-01

  articleSenior author
  PublisherDOI

• A Case of Hyponatremia Due to Unilateral Renal Hypoperfusion from a Type B Aortic Dissection

  Journal of the American Society of Nephrology · 2024-10-01

  articleSenior author
  PublisherDOI

• Point-of-care ultrasound training in nephrology: a position statement by the International Alliance for POCUS in Nephrology

  Clinical Kidney Journal · 2024-08-13 · 24 citations

  reviewOpen access

  Point-of-care ultrasonography (POCUS) has rapidly evolved from a niche technology to an indispensable tool across medical specialties, including nephrology. This evolution is driven by advancements in technology and the visionary efforts of clinicians in emergency medicine and beyond. Recognizing its potential, medical schools are increasingly integrating POCUS into training curricula, emphasizing its role in enhancing diagnostic accuracy and patient care. Despite these advancements, barriers such as limited faculty expertise and 'lack of' standardized guidelines hinder widespread adoption and regulation. The International Alliance for POCUS in Nephrology (IAPN), through this position statement, aims to guide nephrologists in harnessing the diagnostic power of POCUS responsibly and effectively. By outlining core competencies, recommending training modalities and advocating for robust quality assurance measures, we envision a future where POCUS enhances nephrology practice globally, ensuring optimal patient outcomes through informed, evidence-based decision-making. International collaboration and education are essential to overcome current challenges and realize the full potential of POCUS in nephrology and beyond.

  PublisherOA PDFDOI

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

  Journal of Ultrasound · 2023-01-08 · 5 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Insights and observations from a multi-organ nephrology point-of-care ultrasound course

  Clinical Nephrology · 2023-11-24 · 5 citations

  letterSenior author
  PublisherDOI

• Point-of-Care Ultrasound Training in Nephrology: A Leap Forward, Not Merely a Check Mark

  Kidney Medicine · 2023-11-26 · 4 citations

  editorialOpen accessSenior author

  Point of care ultrasonography (POCUS) is rapidly evolving as a component of physical examination in modern medicine. In order to establish a successful nephrology-oriented POCUS program, the following elements are essential. First and foremost, it's important for the nephrology faculty and division leadership to grasp the significance of integrating POCUS training into fellowship curriculum. It has been shown that POCUS improves diagnostic accuracy, reduces time to diagnosis, has positive impact on physician-patient interactions, reduces health care cost burden, and the findings carry prognostic significance [1Smallwood N. Dachsel M. Point-of-care ultrasound (POCUS): unnecessary gadgetry or evidence-based medicine?.Clin Med (Lond). 2018 Jun; 18: 219-224https://doi.org/10.7861/clinmedicine.18-3-219Crossref PubMed Scopus (88) Google Scholar, 2Koratala A. Kazory A. An Introduction to Point-of-Care Ultrasound: Laennec to Lichtenstein.Adv Chronic Kidney Dis. 2021; 28: 193-199https://doi.org/10.1053/j.ackd.2021.07.002Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar, 3Reisinger N. Koratala A. Current opinion in quantitative lung ultrasound for the nephrologist.Curr Opin Nephrol Hypertens. 2023; https://doi.org/10.1097/MNH.0000000000000919Crossref Scopus (0) Google Scholar]. In contrast to prevailing perceptions, POCUS performed by nephrologists goes beyond kidney ultrasound and encompasses an extensive array of sonographic applications, including lung ultrasound, focused cardiac ultrasound, and systemic venous Doppler as a part of comprehensive volume status assessment [4Koratala A. Reisinger N. POCUS for Nephrologists: Basic Principles and a General Approach.Kidney360. 2021; 2: 1660-1668https://doi.org/10.34067/KID.0002482021Crossref PubMed Scopus (16) Google Scholar]. Most medical schools in the US have already incorporated basic POCUS training into their curricula and internal medicine residencies are making efforts to catch up [5Nicholas E. Ly A.A. Prince A.M. et al.The Current Status of Ultrasound Education in United States Medical Schools.J Ultrasound Med. 2021; 40: 2459-2465https://doi.org/10.1002/jum.15633Crossref PubMed Scopus (22) Google Scholar,6LoPresti C.M. Schnobrich D. Novak W. et al.Current Point of Care Ultrasound Use and Training Among Internal Medicine Residency Programs from the 2020 APDIM Program Director's Survey.Am J Med. 2022; 135: 397-404https://doi.org/10.1016/j.amjmed.2021.11.002Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar]. This raises expectations among nephrology fellowship applicants about the specialty-specific POCUS applications they are going to learn during their fellowship. Further, having fellows with prior POCUS training who use it during rounds creates a confusion in the clinical decision-making process if the supervising physicians are not familiar with the findings. Therefore, it is imperative that nephrologists entrusted with teaching responsibilities have proficiency in POCUS, at least image interpretation and clinical integration, if not acquisition. As opposed to procedures such as kidney biopsy that can be delegated to interventionalists, physical examination is an integral component of bedside assessment that clinicians are expected to perform. Ultrasonography is just another physical examination tool that can be deployed at the point of care like the stethoscope and has consistently demonstrated diagnostic superiority over conventional methods [1Smallwood N. Dachsel M. Point-of-care ultrasound (POCUS): unnecessary gadgetry or evidence-based medicine?.Clin Med (Lond). 2018 Jun; 18: 219-224https://doi.org/10.7861/clinmedicine.18-3-219Crossref PubMed Scopus (88) Google Scholar,2Koratala A. Kazory A. An Introduction to Point-of-Care Ultrasound: Laennec to Lichtenstein.Adv Chronic Kidney Dis. 2021; 28: 193-199https://doi.org/10.1053/j.ackd.2021.07.002Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar]. Recognizing these facts prompts divisional faculty members to actively engage with the POCUS program and motivate fellows to incorporate routine scanning, thereby laying a strong foundation for an effective program. Establishing any novel academic program from scratch is a challenging task and the POCUS curriculum is no exception. Expert faculty with a passion for teaching are the key to building a successful POCUS program. Despite growing interest in POCUS, faculty expertise and the range of sonographic applications taught in nephrology fellowship programs remain sparse at this time [7Cook D.L. Patel S. Nee R. et al.Point-of-Care Ultrasound Use in Nephrology: A Survey of Nephrology Program Directors, Fellows, and Fellowship Graduates.Kidney Med. 2023; 5100601https://doi.org/10.1016/j.xkme.2023.100601Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. Nephrology fellowship programs that do not have POCUS-trained faculty tend to rely on experts from other specialties such as emergency medicine and critical care to teach fellows through short workshops or elective rotations. While this is a reasonable initial strategy and fills the void to some extent, it is not a viable long-term option. Though image acquisition remains relatively uniform, the focused clinical questions asked, and clinical integration of the POCUS findings are unique to individual specialties. For example, ensuring adequate decongestion in a patient with cardiorenal syndrome prior to discharge by assessing sonographic markers is more relevant to nephrology compared to emergency medicine where the focus is on acute life-threatening diagnoses. Similarly, quantifying extravascular lung water and right atrial pressure in the outpatient setting (e.g., cardiorenal clinic, dialysis unit) is unique to nephrology. Therefore, nephrology faculty will be able to provide a better perspective on the practical utility of POCUS in specialty-specific clinical scenarios. In addition, faculty from other specialties often cannot dedicate time for longitudinal supervision of nephrology fellows, which eventually curbs fellows’ enthusiasm for learning or even worse, makes them overestimate their skills, potentially leading to patient harm. So, fellowship programs must allocate resources to train their core POCUS faculty via institutional pathways where available or structured certification programs [8Mathews B.K. Zwank M. Hospital Medicine Point of Care Ultrasound Credentialing: An Example Protocol.J Hosp Med. 2017; 12: 767-772https://doi.org/10.12788/jhm.2809Crossref Scopus (13) Google Scholar,9Koratala A. How to get certified in POCUS? NephroPOCUS.com https://nephropocus.com/2020/11/05/how-to-get-certified-in-pocus/ Last accessed: 5/6/2023Google Scholar] with an eventual goal of training the rest of the faculty. Faculty must be provided with dedicated time and support for the administration of POCUS curriculum commensurate with the size of the fellowship program and its configuration; failure to do so leads to burnout, which ultimately results in suboptimal training of the fellows. The amount of work that goes into developing and maintaining a POCUS program is often underrecognized. For example, the duties of a POCUS director include development and curation of educational material, providing direct and indirect supervision, maintaining equipment, ensuring proper documentation, guiding scholarly activity, performing quality assessment, and training other faculty in the division [4Koratala A. Reisinger N. POCUS for Nephrologists: Basic Principles and a General Approach.Kidney360. 2021; 2: 1660-1668https://doi.org/10.34067/KID.0002482021Crossref PubMed Scopus (16) Google Scholar]. Furthermore, faculty must attain minimum competency in POCUS themselves prior to starting a formal training program, which consumes substantial time. This contrasts with setting up a subspecialty clinic such as glomerulonephritis clinic as nephrologists are expected to possess minimum competency in treating glomerulonephritis by the time they graduate from fellowship and can quickly hone their skills afterwards. Additionally, while faculty members interested in research may secure extramural funding to support their time once they have achieved competence, compelling them to generate papers and obtain funding right from the outset could potentially result in subpar research conducted with potentially erroneous inferences. Availability of ultrasound equipment is another key element that impacts the quality of POCUS education. Fellowship programs must consider several factors when procuring ultrasound equipment, not just the cost. In general, low-cost handheld devices have lower image resolution. While it may not affect applications such as lung (involves interpretation of artifacts) and internal jugular vein (superficial structure) ultrasound, low image quality particularly compromises cardiac imaging. Moreover, novice POCUS users may not be able to grasp sonographic anatomy when using such devices. Cost cutting also hinders procuring options such as spectral Doppler, a vital component of advanced hemodynamic assessment. Having these options is important for the faculty to grow their skills and eventually expand the curriculum. Notably, a study that evaluated four commonly used handheld ultrasound devices in the United States found that none of these devices were considered to possess all the desired attributes according to expert users [10Nathanson R. Le M.T. Proud K.C. et al.Development of a Point-of-Care Ultrasound Track for Internal Medicine Residents.J Gen Intern Med. 2022; 37: 2308-2313https://doi.org/10.1007/s11606-022-07505-5Crossref Scopus (3) Google Scholar]. As mentioned, future nephrology fellows will already be exposed to basic sonographic applications such as lung and inferior vena cava during their medical school or residency and expect training in Doppler applications. As such, POCUS programs must be equipped to cater to their needs and expectations. Additionally, the size of the ultrasound monitor is something that is often overlooked. Larger screen size (as opposed to cellphone or a tablet-based display) enables better appreciation of the images/pathology at the bedside when there are multiple learners. On the other hand, portability is important when the equipment must be carried to places such as outpatient dialysis units and offsite clinics. We recommend that programs consider purchasing both cart-based and handheld devices to provide optimal training experience. POCUS scans can be billed for as we described in detail elsewhere [11Northcutt N.M. Reisinger N.C. Nuts and Bolts of a POCUN Program.POCUS J. 2022; 7: 88-93https://doi.org/10.24908/pocus.v7iKidney.15346Crossref Google Scholar,12Koratala A. Olaoye O.A. Bhasin-Chhabra B. Kazory A. A Blueprint for an Integrated Point-of-Care Ultrasound Curriculum for Nephrology Trainees.Kidney360. 2021; 2: 1669-1676https://doi.org/10.34067/KID.0005082021Crossref PubMed Scopus (18) Google Scholar], which helps to offset the equipment costs over time. Indeed, studies have demonstrated that the establishment of a well-structured billing process for POCUS scans can generate net profit [13Adhikari S. Amini R. Stolz L. O'Brien K. Gross A. Jones T. Fiorello A. Keim S.M. Implementation of a novel point-of-care ultrasound billing and reimbursement program: fiscal impact.Am J Emerg Med. 2014; 32: 592-595https://doi.org/10.1016/j.ajem.2014.02.051Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar]. The burden of purchasing ultrasound devices should never fall on individual faculty or trainees. An established workflow with image archiving is critical for establishing a successful POCUS program. It facilitates providing timely feedback for the trainees, billing, and seeking expert opinion when in doubt. If the images are archived and are retrievable from the patient’s chart, the need for multiple specialists to perform repeat exams to answer the same focused clinical question is obviated. It also facilitates quality assurance, which is vital for maintenance and improvement of a POCUS program. Archiving is technically not difficult and can be accomplished with the help of the institutional Information Technology department. Figure 1 lists the key limiting factors and their impact on the quality of the POCUS program. Robust POCUS training programs are necessary to unlock its full potential and explore its utility in areas that pose diagnostic challenges such as hepatorenal dysfunction. Building such programs involves not only motivated faculty but also administrative support, long-term vision as well as interdisciplinary collaboration. Creating me too or check mark curricula just to fill fellowship spots without a proper structure will potentially deteriorate the already dwindling interest in nephrology. Moreover, inadequate training and consequent false sense of confidence could lead to patient harm. Nephrology professional associations should collaborate to formulate guidelines for standardized POCUS curricula, methods of assessing and documenting competency, and pathways for reimbursement. These inter-organizational committees should be comprised of experts with suitable qualifications and a demonstrated history of excellence in teaching POCUS. Beyond fellowship education, practicing physicians are eagerly anticipating longitudinal POCUS training programs with the endorsement of professional societies, leading to certification. This demand was clearly highlighted through feedback received from participants who attended the recent POCUS workshops hosted by the American Society of Nephrology and the National Kidney Foundation led by the authors. It is high time we as a specialty acknowledge the necessity of embracing this skill, which is arguably a breakthrough in bedside clinical assessment after the invention of stethoscope more than two hundred years ago. Authors’ Full Names and Academic Degrees: Abhilash Koratala, M.D.1 and Nathaniel Reisinger, M.D.2

  PublisherOA PDFDOI

Frequent coauthors

• Abhilash Koratala

  Medical College of Wisconsin

  20 shared

• Cameron Baston

  Digestive Care (United States)

  8 shared

• Sadichhya Lohani

  University of Pennsylvania

  7 shared

• Nova L. Panebianco

  University of Pennsylvania

  7 shared

• Forrest F. Lindsay-McGinn

  Kaiser Permanente Vacaville Medical Center

  6 shared

• Felipe Teran

  5 shared

• Kara Ramos

  National Institute of Nursing Research

  4 shared

• Eduardo R. Argaiz

  Tecnológico de Monterrey

  4 shared

Labs

• Reisinger LabPI