Nephrologists Rather Than Intensivists Should Manage Kidney Replacement Therapy in the ICU: CON

Are We in a Crisis?

Who should prescribe and manage acute RRT, more specifically continuous RRT (CRRT) in critically ill patients in intensive care unit (ICU) settings? Is this really a simple black and white issue? Is this debate really framed in a suitable and appropriate context? What essentially drives this issue of who—nephrologists or intensivists—should manage RRT for critically ill patients in the ICU? Does this issue genuinely derive from a foundational core on high-quality care with the patient as a central focus? I remain skeptical and believe questions surrounding this issue deserve frank and transparent dialogue. There would appear to be some record of communicative and collaborative challenges on this issue between these specialties.^1,2

What Is Critical Care and Who Are Intensivists?

ICUs are highly organized and specialized systems of care (medical, nursing, etc.) capable of providing enhanced, around-the-clock, multimodal physiologic monitoring and advanced organ support aimed to rescue rapidly and to sustain life for patients at risk of or with acute life-threatening illness.³ ICUs provide care for the most severely ill patients in the health system and, as such, embody some of the most resource-demanding and stressful settings in acute care hospitals. Intensive care or critical care, as a specialty, remains young relative to established disciplines such as internal medicine and nephrology.⁴ Nonetheless, critical care is now a well-established “all-encompassing” profession, perhaps further recognized and consolidated by its central role in the response to the coronavirus disease 2019 pandemic, with the term “intensivist” now having been formally adopted into our daily lexicon.⁵

Intensivists receive dedicated and comprehensive accredited training focused on severe life-threatening conditions (e.g., shock, sepsis, respiratory failure, liver failure, coma, AKI, end of life, etc.),⁶ on sophisticated and technologically advanced monitoring modalities, and on mechanisms of multiorgan support (including RRT), rather than the single-organ approach of many specialties. Intensivists’ work is integrated in a complex, often strained, multidisciplinary, team-based environment that defines a modern ICU.⁷

Therefore, perhaps clinical context, and the variations in organization that exist across health systems, are important to consider. For example, intensivists are unlikely to consult respirologists for every patient with hypoxia and to manage invasive mechanical ventilation. Likewise, intensivists are not likely to consult cardiologists for every patient with low cardiac output syndrome after surgery and to guide the management of inotropes.⁸ So, should intensivists then consult nephrologists for every critically ill patient in the ICU with AKI and to manage RRT, specifically CRRT? Some offer arguments to advocate for such an approach,^2,9 whereas others tend to suggest otherwise,^10–12 and still some acknowledge that a more nuanced strategy may be desirable.^8,13

AKI is exceedingly common in critical illness, occurring in more than half of those admitted to ICU,¹⁴ making it more frequent than many other ICU syndromes (e.g., sepsis, acute respiratory distress syndrome).¹⁰ Likewise, a substantial proportion of ICU patients with severe AKI receive RRT.¹⁴ Such RRT is commenced near universally for AKI occurring in critically ill patients with multiple dysfunctional or failing organs, rather than for isolated AKI per se.¹⁵ So, is it really feasible to ask the nephrology services of most acute care institutions to practically provide timely, around-the-clock, high-quality, expert consultation to manage this patient volume?

This does not preclude a vital role for nephrology collaboration in ICU settings. In my view, the management of RRT in ICU settings should be directed to clinicians who at a minimum have both (1) a nuanced and integrated understanding of the patient’s burden of critical illness, their trajectory, spectrum of organ support, prognosis, and their overarching philosophy of care (i.e., having a beneficial relationship with the patient and their family); and (2) a deep comprehension of RRT physiology and a nuanced understanding of its prescription and management in critical illness, including an appreciation for when it may be indicated, when it should be avoided, and the potential harm of acute RRT in selected circumstances. Does this then leave us in search of critical care nephrology “unicorns”?

What Is the Worst-Case Scenario?

The worst-case scenario would be any mix of: (1) sole management of acute RRT in the ICU by nephrology, where selected nephrologists are generally uninterested or inexperienced in critical care or AKI, whose services are too busy and often unavailable, who fail to communicate effectively with the ICU team, or whose institutions have limited nephrology resources (e.g., dialysis nurses) such that the timeliness of ICU care is compromised; and (2) sole management of acute RRT in the ICU by critical care, where selected intensivists have little or limited understanding of the broad principles of RRT, who fail to recognize the limitations in their knowledge and other blind spots (e.g., AKI not attributed to hypotension or sepsis), who do not effectively communicate with the nephrology service, or whose ICU teams have limited experience with RRT or the organization of a RRT program. Although this may seem extreme, I would hazard that in many jurisdictions, aspects of both these scenarios manifest not infrequently. Surely there must be some middle ground, whereby again, the patient is the central tenet of care¹⁶ (Table 1).

Table 1.

Relative comparison of ICU versus nephrology-directed RRT in the ICU⁹

RRT Attributes	Intensive Care Unit	Nephrology
Program administration	Specific to individual ICU or integrated ICU region; aligned with other ICU-specific programs	Integrated into larger RRT programs that include ward-based or outpatient-based RRT services
Education	ICU specific, focused primarily on CRRT, can be led by ICU-based clinical educators	Nephrology-based clinician training adapted to ICU setting
KPIs and quality improvement	Well-established legacy of KPI reporting in ICU settings; specific KPI for CRRT less well developed	Adapted from well-established KPI reporting in ESKD and chronic RRT programs
Availability	Immediate, ICU team inserts catheter, skilled ICU nurse primes and operates all aspects of CRRT machine	Potentially delayed, necessitating external consultation±nephrology-based nursing availability
Modality	Predominantly CRRT, external consultation for transition from CRRT to intermittent RRT	Any modality; however, potentially limited training/experience with CRRT
Individualized therapy	Protocol driven, less flexibility	Protocol driven, expertise to adapt to specific circumstances
Costs	Higher consumable costs for CRRT, ICU nurse trained to manage CRRT machines, lower human resource costsa	Lower consumable costs with intermittent RRT (if predominant modality, no difference with CRRT), higher human resource costs (i.e., dialysis nurse)
Care transition and follow-up	Potentially represents missed opportunity, external consultation for care transition	Continuity to facilitate longer follow-up after ICU

ICU, intensive care unit; CRRT, continuous RRT; KPI, key performance indicator.

^aCost efficiency further improved by ICU nurses trained in provision of intermittent RRT.

What Is the Role of the Nephrologist?

As aforementioned, nephrologists can and should be vital in the care of critically ill patients in ICU settings.¹³ Nephrologists can offer added expertise and insights for patients with AKI and diagnostic uncertainty (e.g., renal vasculitis, glomerulonephritis, interstitial nephritis), for management of patients with complex electrolyte derangements (e.g., hyponatremia), for patients who fail to liberate from RRT and need transition to prolonged intermittent RRT, and for patients in need of specific therapeutic interventions (e.g., therapeutic apheresis or plasma exchange). Nephrology can offer a breadth of knowledge and expertise to the management of patients with preexisting complex CKD (e.g., glomerulonephritis), ESKD receiving maintenance dialysis (e.g., hemodialysis or peritoneal dialysis), and in those who have received kidney transplantation (e.g., immunosuppression).

Whereas nephrology expertise may add insight into the avoidance of perceived unnecessary or futile RRT,¹³ which intensivists may be more susceptible of providing, this may be limited by nephrologists having only a snapshot of the patients’ critical illness and overall trajectory. Nephrologists may also have limited knowledge of what constitutes futility in critical illness, navigating end-of-life care in ICU settings, and a limited or no prior relationship with the patient and their family.

Perhaps most important, nephrologists have a crucial role to ensure continuity during transitions of care from the ICU to the ward, particularly when transferred to non-nephrology services, and ultimately among those who transition into the community to survey for the sequelae of CKD and other legacy complications.¹⁷ This should not only encompass those who remain dialysis dependent, but also consider those patients who had an episode of severe AKI not treated with RRT, or those treated with RRT whose kidney function recovered to liberate while still in the ICU.

What Is the Common Ground?

The clinical, administrative, and educational lead for acute RRT services in ICU settings could be driven primarily by nephrology, in collaboration with ICU.² One solution would be for nephrology to allocate dedicated resources and develop a specialized ICU nephrology team, whose exclusive responsibility is the sole provision of 24/7 nephrology and RRT-related services in the ICU. This would enable and ensure continuous communication, care integration, and alignment with the ICU team and the evolving care needs for critically ill patients. This might be feasible in large institutions supported by a high-volume of critically ill patients receiving RRT and to justify the clinical service model; however, such an approach may simply not be feasible in most or smaller institutions.

But is this really a necessity or in fact desired by all stakeholders? What are the organizational and clinical barriers to having the ICU team lead the provision of a high-quality, safe, and lean acute RRT service, specifically CRRT, in collaboration with nephrology, as is currently done in numerous jurisdictions around the world? So much of this circular argument is context specific and seemingly motivated by concerns beyond the bedside.

The middle ground and the mystical “unicorn” we are searching for to lead may simply be the engaged nephrologist or intensivist who has undertaken focused clinical training in both disciplines and remains wholeheartedly committed to the subspecialty of critical care nephrology in the ICU, both clinically and academically. Although dual training and certification in both disciplines is now relatively common,¹⁶ this may not always be practical or welcome.

Disclosures

S.M. Bagshaw reports consultancy for Baxter Healthcare Corp., BioPorto, Inc., and CNA Diagnostics, Inc.; ownership interest in CNA Diagnostics, Inc.; research funding from Baxter Healthcare Corp.; honoraria from Baxter Healthcare Corp.; an advisory or leadership role for Baxter Healthcare Corp. and CNA Diagnostics, Inc.; being on the editorial board for Critical Care; being on the adjudication committee for BioPorto; and participated in a speakers’ bureau for Baxter Healthcare Corp.

Funding

None.

Author Contributions

S.M. Bagshaw wrote the original draft of the manuscript.