Abstract: FR-PO079
Glucose, Citrate, Calcium, Na, HCO3-, and Phosphate Mass Balance Studies in Ex Vivo Simulations of a Simplified CVVHDF-RCA Protocol That Works Regardless of Citrate Metabolism
Session Information
- AKI: Clinical Outcomes, Trials
November 08, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 102 AKI: Clinical, Outcomes, and Trials
Authors
- Yessayan, Lenar Tatios, University of Michigan, Ann Arbor, Michigan, United States
- Szamosfalvi, Balazs, University of Michigan, Ann Arbor, Michigan, United States
Background
We developed a new, simplified approach to CRRT-RCA prescribing with commercially available equipment and CRRT fluids. It is important to study the mass balance of glucose (Glu), citrate, Ca, Na, HCO3-, and phosphate in an ex vivo system to demonstrate that a new CRRT protocol will approximate physiologic values of these solutes in the patient even in the absence of citrate metabolism.
Methods
We used a recently FDA-approved CRRT machine to deliver CVVHDF-RCA in an ex vivo system (Figure 1). IV pumps delivered infusions of urea/creatinine, ACDA and calcium. Human PRBCs and plasma filled the CRRT circuit and reservoir to target Hct. Commercial CRRT fluids were spiked to 139 or 140Na, 4K, 35HCO3, 1.5Mg, 0Ca, 1.5mMPhos with 0 or 5.5mMGlu. A 136 mM CaCl2 solution in D50.9% or 0.9% saline was paired with 0 or 5.5mM Glu CRRT fluid, respectively. We tested QB 20, 40, 60 ml/min and Hct 45, 33, 21. ACDA (ml/h) = 2.5* QB, QDialysate (ml/h) = 30 * QB, QReplacement (ml/h) = 10 * QB, QCa (ml/h) about 0.7 * QB and Qurea (ml/h) = QB. Blood and fluid samples were collected and analyzed by I-Stat point-of-care device and in the laboratory.
Results
The reservoir iCa was 1-1.3 mM. All circuit iCa was < 0.25 mM. Reservoir Na was 135-140 and other major electrolytes were around physiologic values. The reservoir glucose remained in the 70-150 mg/dL range with either CRRT fluid/Ca-infusion pair and glucose dialysance was 80-90% of CRRT circuit plasma flow. Single pass citrate removal on the filter was 80-90% and clinically significant citrate accumulation in the reservoir was avoided.
Conclusion
Ex vivo simulation suggests that the new CVVHDF-RCA protocol will approximate normal systemic solute levels without citrate metabolism. I-stat bedside glucose dialysance may be used in a clinical study to indirectly monitor plasma citrate- and Ca-clearance.
Funding
- Private Foundation Support