Improving Nephrology Care With Point-of-Care Ultrasound

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Residents at the Northwell Health System using point-of-care ultrasound to assess vasculature.
Residents at the Northwell Health System using point-of-care ultrasound to assess vasculature.

Each July, hundreds of fellows from around the United States gather for a 3-day in-depth hands-on course in point-of-care ultrasound for the American College of Chest Physicians (“Chest”). Over the last decade, the course instructors have trained more than 1000 fellows and 3000 attending physicians, including intensivists, hospitalists and residents. Analysis of their outcomes prove that they have a recipe for training success.1 Mangala Narasimhan, DO, and Paul Mayo, MD, teach the course, but they are not nephrologists. Rather, they are intensivists, and the fellows they train are not nephrology fellows, but pulmonary and critical care fellows. Nevertheless, their course could have a profound impact on the nephrology community.

At North Shore University Hospital and the Long Island Jewish Medical Center, of the Northwell Health System and the Hofstra Northwell School of Medicine in New York, Drs Narasimhan and Mayo have made whole body point-of-care ultrasound the standard of care in the intensive care unit (ICU). Each day, they round in the ICU with their fellows and use the ultrasound probe as an extension of their physical examination, a new stethoscope for the 21st Century.

Our faculty at the Northwell Health Division of Kidney Diseases and Hypertension work closely with the ICU staff on a daily basis and became interested in what the ICU staff was doing with the ultrasound probe. We observed that physicians who used the ultrasound probe at the point of care made a tremendous clinical impact. They were able to answer specific questions that came up on rounds immediately. This information, along with history and traditional physical examination, helped make timely decisions regarding the critically ill. Recognizing an opportunity, nephrology fellowship program director Hitesh H. Shah, MD, and critical care nephrologist Richard Barnett, MD, approached Drs Mayo and Narasimhan about developing a formal training course designed specifically for nephrologists.

In the summer of 2015, we held our first nephrology training course in point-of-care ultrasonography at Northwell. The curriculum was adapted from the Chest course given by our critical care faculty. The 3-day course was condensed into a single half-day course. In our first year, during the first half of the course, residents and fellows learned how to image the kidney and assess size, cortical thickness, and to look for hydronephrosis. They also learned how to assess bladder volume and determine if Foley catheters were in place and working. The second half of the course was devoted to using ultrasound to assess volume status by examining the lungs.

The course began with a standardized patient, an experienced sonographer, and a large video monitor. The instructor applied the probe to the patient's abdomen and the image was projected on the screen. We were taught the basics of ultrasonography and how to adjust depth and gain. Once the instructor demonstrated a thorough examination of the kidneys and bladder, the learners broke up into groups. Half of the class stayed behind and practiced interpreting normal and abnormal images. The other group subdivided into smaller groups with a training ratio of 1 instructor to 3 students.  These small groups practiced scanning the kidneys and bladder on a standardized patient with the assistance of an expert instructor. The groups switched, and after a short break reconvened to repeat the same schedule for lung ultrasonography.

The challenge for our nephrology division was the thought shift that came from using lung ultrasonography for assessing volume status. Many in our division were unaware that lung ultrasonography could be used to assess extravascular lung water. As it turns out, when an ultrasound beam hits a thickened interlobular septum it generates reverberation artifacts that jut away from the pleural surface like a bright white rocket.  These lung rockets have come to be known as “B lines.” Evidence has shown that the quantity of B Lines directly correlates with pulmonary capillary wedge pressure and with extravascular lung water by thermodilution.2  Not surprisingly it has been shown that B Lines are predictably reduced immediately after ultrafiltration.3  In an important work out of Italy, Carmine Zoccali, MD, and colleagues showed that pulmonary congestion on lung ultrasound is a significant predictor of mortality above and beyond traditional cardiac risk factors.4 What remains unclear is whether lung ultrasound can be used to tailor target weight prescription. This is an area of active investigation, and results of the Lung Water by Ultrasound Guided Treatment in Hemodialysis Patients (LUST) trial hopefully will provide guidance (clinicaltrials.gov: NCT02310061). Regardless, it is clear that lung ultrasound can be a very useful tool for the nephrologist. The absence of B lines effectively rules out alveolar interstitial syndrome, including pulmonary edema, invaluable information for the ultrafiltration prescription.

After our initial training course, some members of our faculty approached point-of-care ultrasound with vigor. It was almost as if we had re-entered medical school to relearn physical examination skills. To be certain, a single half-day training course is not nearly enough to learn how to do comprehensive renal ultrasonography, but it gave us a start and allowed us to have enough knowledge to then practice on our own. 

In our experience, there are discrete, practical questions that can be answered immediately at the point of care with an ultrasound probe. Does the patient have signs of urinary retention?  Does the patient have hydronephrosis?  Is the Foley catheter balloon blocked against the bladder wall?  How big are the kidneys? Does the patient have evidence of extravascular lung water?  These are questions that are useful at the very moment of initial consultation, not hours later when an radiology department study would be performed. Cysts or masses, kidney stones, and thickened bladder walls are all best left to the experienced radiologist.

At the National Kidney Foundation's 2017 Spring Clinical Meetings, we and a faculty colleague, Varun Agrawal, MD, will join Dr. Mayo in offering a half-day pre-course replicating the course given at our center. The course will be held on April 18, and we will have an instructor-to-learner ratio that will enable everyone to get a thorough experience with a hand-held ultrasound device. Our hope is that this course is a first step to bringing point-of-care ultrasonography into common clinical nephrology practice, allowing us to enhance care for our patients. 

To register visit: https://www.kidney.org/spring-clinical/registration/fees.

The authors are affiliated with Hofstra Northwell School of Medicine in Hempstead, New York. Drs. Ross and Jhaveri are in the division of nephrology and Dr. Narasimhan is in the division of pulmonary/critical care.

References

  1. Greenstein Y, Littauer R, Narasimhan M, et al. Effectiveness of a critical care ultrasonography course. Chest 2017;151:34-40.
  2. Agricola E, Bove T, Oppizzi M, et al.  “Ultrasound comet-tail images”: A marker of pulmonary edema.  Chest 2005;127:1690-1695.
  3. Noble VE, Murray AF, Capp R, et al. Ultrasound assessment for extravascular lung water in patients undergoing hemodialysis.  Chest 2009;135:1433-1439.
  4. Zoccali C, Torino C, Tripepi R, et al.  Pulmonary congestion predicts cardiac events and mortality in ESRD.  J Am Soc Nephrol 2013;24:639-646.
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