By Ryan Marthaler, Vice President, Product Marketing and Business Development, Nuwellis
Fluid overload is one of the most persistent and consequential challenges in modern healthcare. Yet fluid overload is often treated as an episodic problem, managed only after patients become difficult to stabilize or fail conventional therapy. For clinicians, this creates a familiar and difficult gap: diuretics may no longer be effective, but dialysis-based therapies may not be the right next step when the primary need is volume management rather than solute clearance.
Despite its prevalence, fluid overload is often addressed in isolated episodes rather than through a coordinated, longitudinal strategy. This approach falls short for many patients, particularly those whose condition is driven by complex interactions between the heart and kidneys. For healthcare systems, industry leaders, and investors watching the evolution of cardiorenal care, this gap represents a larger shift: fluid management is moving from a single-intervention mindset toward an integrated platform approach that combines monitoring, therapy, and data-informed clinical decision-making.
As the industry continues to advance, there is a growing recognition that fluid management must be approached as a continuous process supported by integrated solutions that span monitoring, therapy, and clinical decision-making.
A Common and Costly Clinical Challenge
Fluid overload is the harmful buildup of excess water and salts in the body that the heart, kidneys, or treatments cannot remove. It is associated with a range of serious conditions, including heart failure, kidney disease, acute kidney injury, pediatric cardiac and renal conditions, and complications following surgery or critical illness.
The clinical and economic impact is significant. Fluid overload is a leading cause of costly hospital readmissions within 30 days following cardiac surgery. In critically ill patients in the ICU, it is associated with a markedly increased risk of 90-day mortality. In pediatric populations, fluid overload is also associated with significant increases in mortality.
In heart failure alone, approximately 90 percent of hospitalizations are driven by symptoms of fluid overload. These statistics highlight the central role fluid management plays across a wide range of care settings and patient populations.
They also point to a broader industry issue: fluid overload is not confined to a single specialty, site of care, or patient population. It is a cardiorenal challenge that can emerge early, worsen quickly, and become increasingly difficult to manage when treatment options are fragmented.
The Clinical Gap Between Diuretics and Dialysis-Based Therapy
Diuretics remain the standard of care for managing fluid overload. While effective for many patients, they are not sufficient for all. A subset of patients develop resistance to diuretics, leaving clinicians with limited options to manage fluid balance effectively.
This challenge is particularly pronounced in patients with advanced cardiorenal conditions, where both heart and kidney function are compromised. In these cases, inconsistent or inadequate fluid removal can contribute to worsening outcomes, repeated hospitalizations, and increased strain on healthcare systems.
For clinicians, the question is often not whether fluid should be removed, but how to remove it safely, predictably, and at the right time. Some patients need more than escalating doses of diuretics, but do not yet require dialysis-based therapy for solute clearance. Others may need volume management between dialysis or CRRT treatments. In these situations, the ability to decouple fluid removal from solute management can create a more targeted approach to patient care.
Addressing this gap requires solutions that can provide controlled, predictable fluid removal independent of kidney function, while also supporting clinicians in making informed decisions throughout the course of care.
Precision Ultrafiltration in Clinical Practice
Precision ultrafiltration technologies are designed to meet this need by enabling controlled removal of isotonic fluid in patients with fluid overload who are unresponsive to medical management, including diuretics. These systems allow clinicians to manage volume status with a high degree of control, supporting therapy optimization while helping address a critical gap between pharmacologic therapy and dialysis-based escalation.
The Aquadex SmartFlow system is one such solution, delivering controlled and predictable isotonic fluid removal for both adult and pediatric patients weighing 20 kilograms or more. It is indicated for temporary use of up to eight hours, as well as extended use in hospitalized patients who require longer treatment durations.
Clinical experience and published evidence have supported the role of simplified ultrafiltration in carefully selected patients with fluid overload, including those who are diuretic unresponsive or require controlled volume management in highly monitored settings. The Aquadex system is also designed to fit within hospital workflows, with clinical resources that support appropriate patient selection, therapy management, and multidisciplinary adoption.
For hospitals, the value is not only clinical. Technologies that fit into existing workflows, support multidisciplinary adoption, and can be used across appropriate care environments may help systems address a common and costly challenge with greater consistency.
From Single Therapy to Integrated Fluid Management
Effective management of fluid overload requires more than a single intervention. It requires a coordinated approach that supports patient care across acute and chronic settings. This includes not only therapy but also monitoring and data-informed clinical decision-making.
Nuwellis is focused on developing technologies that address this need across the full heart-kidney continuum. The Company’s portfolio includes both commercially available and development-stage technologies designed to support patient care through volume control, timing of intervention, and therapy optimization.
This is the strategic evolution now underway at Nuwellis. The company is advancing from a single-device story toward a broader cardiorenal platform designed around precision fluid management. That platform approach brings together therapy, diagnostics, monitoring, and future product development to help clinicians better understand when to intervene, how to manage fluid removal, and how to support patients across different points in their care journey.
The acquisition of Rendiatech, an Israeli-based developer of automated kidney function monitoring technology, is an important step in that strategy. By adding diagnostic capabilities designed to support clinical decision-making in critically ill patients, Nuwellis is expanding beyond therapy alone and building toward a more integrated model of care.
Together, these capabilities reflect a broader evolution from a single device approach to a more comprehensive fluid management platform.
Addressing the Needs of Pediatric Patients
The need for precise fluid management is especially critical in pediatric populations. Children, particularly those in neonatal, pediatric, and cardiovascular intensive care units, require careful management due to their small blood volumes and sensitivity to fluid shifts.
The Aquadex therapy platform is cleared by the Food and Drug Administration (FDA) for use in pediatric patients weighing 20 kilograms and above. Nuwellis recently completed a successful pre-submission meeting with the FDA regarding the proposed label expansion of the Aquadex to support pediatric patients weighing 5 kg and above. The meeting provided feedback on the Company’s proposed regulatory strategy, including a pathway toward a 510(k) submission, which Nuwellis anticipates submitting to the FDA by the end of 2026.
This proposed expansion reflects a clear clinical need. Smaller pediatric patients have less margin for error, making precision, control, and therapy design especially important. In these settings, fluid management is not simply about removing volume. It is about giving clinicians the ability to remove fluid in a way that is carefully matched to the patient’s size, condition, and tolerance.
Clinical demand continues to grow, with providers increasingly adopting this approach in pediatric settings. Nuwellis has expanded its pediatric footprint to 47 centers nationwide, including six of the top 10 children’s hospitals as ranked by U.S. News and World Report. Pediatric use now represents approximately 50 percent of total U.S. revenue and is the Company’s largest and fastest-growing category.
Looking ahead, the Company is working to expand the current labeled weight indication and is developing next-generation technology designed to support even smaller patients. The Vivian system, currently in development and supported by a 3-million-dollar National Institutes of Health grant, is intended to support patients as small as 2.5 kilograms.
Building an Integrated Cardiorenal Platform
The future of fluid management lies in integration. By combining precision ultrafiltration with diagnostic monitoring and data-informed insights, healthcare providers can better manage patients across the full continuum of care.
Nuwellis is advancing along this path, building a platform that brings together therapy and diagnostics to address complex cardiorenal conditions. This approach reflects a broader industry shift toward solutions that are scalable across patient populations and adaptable to different care environments.
For healthcare professionals, this means tools that can support more informed and timely intervention. For hospital leaders, it means a more coordinated way to address a condition that contributes to readmissions, resource utilization, and care complexity. For investors and industry observers, it points to a larger opportunity: fluid management is becoming a defined category within cardiorenal care, and integrated platforms may play an important role in shaping that future.
A More Precise Future for Fluid Management
Fluid overload is a complex condition that requires coordinated management across the entire patient journey. From acute intervention to ongoing care, the ability to monitor, assess, and treat fluid imbalance is essential to improving outcomes in both adult and pediatric populations.
Advances in precision ultrafiltration and integrated monitoring technologies are helping to address this need. By supporting clinicians with tools that enable controlled therapy and informed decision-making, the healthcare system can move toward a more consistent and effective approach to fluid management.
As innovation continues across the cardiorenal continuum, the opportunity is clear. Fluid management must become more precise, more connected, and more proactive. The next phase of care will require technologies that help clinicians identify fluid imbalance earlier, intervene with greater control, and support patients across changing levels of acuity.
Nuwellis is building toward that future by advancing a platform that connects precision ultrafiltration, monitoring, pediatric innovation, and data-informed decision-making. The goal is not simply to remove fluid. It is to help clinicians manage fluid with greater confidence, at the right time, for the patients who need it most.