Critical Care Nephrology: an Appealing Subspecialty for Young Nephrologists

Marco Fiorentino

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Many exciting opportunities and subspecialties have emerged within the field of nephrology. Among these, critical care nephrology has become an important specialty in both clinical and research settings. Acute kidney injury (AKI) is an increasingly recognized adverse outcome among critically ill patients, and its impact is both devastating and often underestimated (1).

Several critical care nephrology programs have been created in recent years to provide clinical care, research, and educational programs to interested trainees. The Center for Critical Care Nephrology in Pittsburgh is an example of the growing interest in promoting a multidisciplinary model of basic, translational, and clinical research to prevent and cure AKI in critically ill patients. However, the role of the nephrologist in the intensive care unit (ICU) is still an area of debate, as opinions regarding whether a nephrologist should be consulted vary widely across different institutions (2).

Both the prompt identification of high-risk patients as well as the correct management of AKI require a strong collaboration between critical care physicians and nephrologists. AKI is a multifactorial syndrome with a wide range of prevalence, pathophysiology, and different therapeutic approaches in the ICU, and nephrologists must have adequate intensive care training to ensure high-quality and efficient care of these patients. Complicated electrolyte and acid-base disorders are common in the ICU and require a robust knowledge of renal physiology. As such, the nephrologist needs to be an early and active participant in guiding and assisting critical care teams in the interpretation of data.

Furthermore, the nephrologist must play an active role in implementing strategies to minimize the risk of severe complications. He or she may assist with avoiding potentially harmful interventions such as the use of nephrotoxic medications, contrast exposure, and with over- or under-diuresis. In addition, the nephrologist can ensure early and appropriate implementation of certain treatment strategies. Early nephrology engagement is crucial when renal replacement therapy (RRT) is required, not only with regard to appropriate timing, but also in relation to choosing the optimal modality, etc. Other therapeutic options such as plasmapheresis and hemadsorption may be appropriate and are also often under the control of nephrologists. A multidisciplinary team consisting of the nephrologist, critical care physician, nurse, and pharmacist is often suggested in the ICU to deliver the right prescription in order to personalize the treatment and maximize its efficacy.

Recently, Ronco and colleagues provided a practical algorithm to better identify patients at high risk for AKI. They proposed that a Nephrology Rapid Response Team (NRRT) manage these high-risk patients, defining AKI causes and stages and aiming to avoid renal and non-renal long-term consequences (3). Moreover, drugs and iatrogenic interventions may often overlap with other AKI exposures and contribute to AKI. The nephrologist may be invaluable in assisting in drug prescription and dosing in ICU patients: potential nephrotoxic drugs may be substituted with less or non-nephrotoxic ones or they may be dosed according to patients’ renal function. This is a big issue in ICU patients, since all formulas that estimate renal function assume a stable serum creatinine. Thus, a strong collaboration between nephrologists and pharmacists is crucial to find the right balance between risks and benefits of medications.

Last, adequate follow-up of AKI patients after ICU and hospital discharge is required because evidence has shown that even partial recovery from AKI episodes increases the risk of progression to chronic kidney disease and premature mortality (4, 5).

Value of collaboration between young nephrologists and intensivists

Beyond the advantages of collaboration between intensivists and nephrologists at the bedside, young nephrologists should partner with intensivists and other specialists in research programs. Many aspects of AKI are still unknown. There is a general consensus about the weakness of the standard criteria for AKI, and the search for the “kidney troponin” is ongoing. Several AKI biomarkers have been evaluated in past years and, more recently, cell-cycle arrest biomarkers have been validated as an early alarm. However, many questions remain about which populations would benefit from such testing, as well as the methods for using these biomarkers in clinical practice. Accurate clinical trials of the biomarkers are not possible until these questions are answered.

There is also discordance about whether or not early initiation of RRT in critically ill patients results in better outcomes (6, 7). In addition, much is still unknown about the pathogenesis of AKI (e.g., septic-AKI vs. non-septic AKI) and the non-pharmacological management of AKI (e.g., preferred type and amount of fluid for resuscitation). Research collaboration between intensivists and nephrologists will be critical in improving outcomes in AKI patients.

Many exciting educational opportunities for fellows and young nephrologists are available in critical care nephrology (Table 1). Several multidisciplinary training programs and courses on topics such as AKI and continuous RRT are available around the world. Attending these courses could not only improve AKI knowledge and increase awareness of critical care nephrology, but it could also help foster interest in the field for future nephrology trainees.

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Critical care nephrology is an emerging and challenging area in our field that deserves our continued attention. The new generation of nephrologists must be ready to collaborate with intensivists to improve the care of ICU patients, educate multidisciplinary teams, develop procedures and protocols, and perform basic and clinical research to better understand AKI pathophysiology.

December 2017 (Vol. 9, Number 12)

References

1. Kellum JA. Why are patients still getting and dying from acute kidney injury? Current Opinion in Critical Care 22; 6:513–519.

2. Askenazi DJ, et al. Optimal role of the nephrologist in the intensive care unit. Blood Purification 2017; 43:68–77.

3. Rizo-Topete LM, Rosner MH, Ronco C. Acute kidney injury risk assessment and the nephrology rapid response team. Blood Purification 2017; 43:82–88.

4. Kellum JA, Bellomo R, Ronco C. Kidney attack. J Am Med Assoc 2012; 307: 2265–2266.

5. Uchino S, et al. Acute renal failure in critically ill patients: a multinational, multicenter study. J Am Med Assoc 2005; 7:813–818.

6. Gaudry S, et al. Initiation strategies for renal-replacement therapy in the intensive care unit. N Engl J Med 2016; 375:22–133.

7. Zarbock A, et al. Effect of early vs. delayed initiation of renal replacement therapy on mortality in critically ill patients with acute kidney injury: the ELAIN randomized clinical trial. J Am Med Assoc 2016; 315:2190–2199.