Over time, the characteristics of the acute renal failure (ARF) patient population in the ICU have changed considerably to the point now that ARF routinely develops in the setting of concomitant cardiopulmonary failure (i.e. ‘multi-organ failure’).
Multi-organ failure is usually due to sepsis, which is the etiology of ARF in approximately 50 per cent of patients. Circulatory failure leads to hemodynamic instability, resulting in the need for large volumes of intravenous fluid and vasoactive medications for blood pressure support.
Many experts consider conventional hemodialysis to be an unsuitable therapy in the ICU due to its propensity to exacerbate the hemodynamic instability so common in ARF patients. Continuous renal replacement therapy (CRRT) was developed specifically to address the clinical condition of critically ill ARF patients.
The fundamental concept of CRRT is the use of extended treatment time (i.e, continuous therapy) as a way to provide renal replacement in such a manner that hemodynamic perturbations are avoided.
In addition to large fluid removal requirements, the solute removal requirements are also significant for a critically ill ARF patient. The common clinical conditions leading to ARF, such as sepsis, trauma, and certain surgical procedures, create a highly catabolic state in which there is accelerated tissue breakdown.
This tissue breakdown leads to a high generation rate of toxins and, in the setting of compromised renal function, retention of these toxins in the bloodstream. It is well recognised that CRRT’s dose delivery capabilities are superior to those of conventional hemodialysis.
Continuous renal replacement therapy actually represents a spectrum of dialysis modalities used specifically for critically ill ARF patients. These modalities are: slow continuous ultrafiltration (SCUF); continuous venovenous hemofiltration (CVVH); continuous veno-venous hemodialysis (CVVHD); and continuous venovenous hemodiafiltration (CVVHDF). In 1995, Gambro introduced the Prisma® system as the first integrated CRRT device addressing the unique requirements of the ARF population.
Over the past decade, the needs of the critically ill ARF population have continued to evolve, especially with respect to higher dose delivery requirements. To meet these evolving needs, the Prismaflex® system was launched in 2004 as Gambro’s nextgeneration system.
A key feature of this system is a wide range of blood and fluid flowrate capabilities that enable clinicians to deliver therapy doses recently demonstrated to improve survival in critically ill ARF patients. In addition, the Prismaflex® system offers the full range of therapeutic modalities described above to meet the clinical needs of the diverse ARF population.
As the Prisma® system has been the most widely used CRRT device in the world for several years, many of its features are retained in the Prismaflex® system. These features include integrated blood and fluid pumps, a dedicated cassette, and a gravimetric system for the precise control of fluid balance needed in the hemodynamically unstable ARF population.