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Abstract: FR-PO609

CVVH as Therapy for Severe Metabolic Alkalosis

Session Information

  • Trainee Case Reports - III
    October 26, 2018 | Location: Exhibit Hall, San Diego Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Trainee Case Reports

  • 902 Fluid and Electrolytes: Clinical

Authors

  • Seethapathy, Harish Shanthanu, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Choi, John Yongjoon, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Fenves, Andrew Z., Massachusetts General Hospital, Boston, Massachusetts, United States
Introduction

Untreated severe metabolic alkalosis (pH>7.6) can lead to devastating clinical consequences such as seizures and coma. We describe the use of continuous veno-venous hemofiltration (CVVH) in the management of a patient with severe metabolic alkalosis.

Case Description

A 51-year-old male with advanced diffuse large B-cell Lymphoma was admitted for high-dose methotrexate infusion as part of his 6th cycle of chemotherapy (R-CHOP plus methotrexate). He received oral and intravenous sodium bicarbonate to maintain high urine flow rates (>100cc/hour) and a urine pH>7.5 to aid methotrexate excretion. He sustained an AKI (peak Cr of 2.5mg/dL; baseline 0.8mg/dL) two days after the infusion. Serum methotrexate levels, which were followed q12h were persistently high (>6umol/L) and isotonic sodium bicarbonate (250cc/hour) was continued. A week later, he developed altered mental status and respiratory failure requiring ventilator support. An arterial blood gas showed a pH of 7.60, pCO2 of 51mmHg and his HCO3 was 46mmol/L. He had received a total of 20L of isotonic sodium bicarbonate. His pH worsened to 7.69 on the ventilator and we were consulted. We initiated CVVH on a citrate bath with a blood flow of 150mL/min and a replacement fluid rate at 800mL/min. Our aim was slow and steady correction of alkalosis - we achieved that over the next 12 hours with a drop in his pH from 7.69 to 7.52. CVVH was terminated after 24 hours. In the next few days, he was extubated and his mental status and renal function returned to baseline.

Discussion

Metabolic alkalosis has traditionally been treated with an acid such as hydrochloric acid (HCl) or an acid precursor such as ammonium chloride (NH4Cl). Issues with availability and the need for reconstitution and specific guidelines for administration (in the case of HCl) limit their use. CVVH is readily available and most ICUs can initiate CVVH within a few hours. There are no specific prescription guidelines to treat metabolic alkalosis. While conventional hemodialysis has been described as a treatment modality, effects of rapid correction of pH are unknown. We successfully achieved a gradual correction of alkalosis using a bicarbonate free bath with slow clearance parameters and constant monitoring. To our knowledge, this is one of the first cases describing the use of CVVH for correction of metabolic alkalosis in the setting of AKI.