ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005


The Latest on Twitter

Kidney Week

Abstract: PO1108

Enhanced Diuresis with Sequential Nephron Blockade

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

  • 902 Fluid, Electrolyte, and Acid-Base Disorders: Clinical


  • Alonso, Shawn, University of Miami School of Medicine, Miami, Florida, United States
  • La, Raymond T., University of Miami School of Medicine, Miami, Florida, United States
  • Valdes Sanchez, Chavely, University of Miami School of Medicine, Miami, Florida, United States
  • Valle, Gabriel A., University of Miami School of Medicine, Miami, Florida, United States

Achieving volume control in patients with severe edema can be challenging, as diuretic resistance may occur. In such cases, sequential nephron blockade (SNB), a targeted multi-diuretic use strategy should be considered.

Case Description

A 60-year-old woman with HIV and Dilated Cardiomyopathy s/p CRT-D presented with dyspnea and anasarca despite torsemide and losartan. In the ED she weighed 370 Lbs., had stable hemodynamic parameters, hypoxemia, diffuse lung infiltrates and low CD4 count. Oxygen, IV loop diuretics and Bactrim were initiated for concerns of PCP and HF. Despite an average UO of 3 L/day she had no meaningful weight loss, protracted lung congestion, hyponatremia and developed radiocontrast nephropathy after CTA. Fluid restriction and SNB with IV thiazide and loop agents were instituted. Tolvaptan was added intermittently and led to an impressive diuresis of 8-11 L/day, restored normonatremia and was hemodynamically and metabolically well tolerated. Within 12 days, weight loss of 154 Lbs. was achieved with major clinical improvement.


Loop agents are a mainstay for diuresis in patients with volume overload. However, diuretic resistance can occur through various mechanisms, including hypertrophy of the distal nephron and loss of function due to AKI.
SNB provides a unique approach by strategically targeting ultrafiltrate dynamics in a stepwise manner and interfering with fluid reabsorption within various tubular segments. Central to this premise is the ability to maximize drug bioavailability and parenteral administration is initially necessary. Close hemodynamic and metabolic surveillance are mandatory as the mobilization of vast amounts of extracellular fluid may result in significant complications. Remarkably, in this case, while her eGFR was 25% she achieved 11 L diuresis (30% of UF) safely. This underscores the enormous capacity for fluid sequestration in the extracellular space and the crucial role of trans-compartmental fluid shifts in HF.
SNB has been available for years and various diuretics combinations are plausible. This case exemplifies the effectiveness of a novel regimen with vaptans in promoting voluminous diuresis and aquaresis, improving outcomes and decreasing length of stay.