William Strode
Pronouns: he/him
Research Mentor(s): Alvaro Rojas-Peña
Research Mentor School/College/Department: Department of Surgery-Transplantation / Medicine
Program: UROPF
Session: Session 1 (9:00am – 9:50am)
Authors: William Strode, Jensyn VanZalen, Jamie Ho, Megan Stein, Gergely Lautner, Orsolya Lautner-Csorba, Robert H. Bartlett, Alvaro Rojas-Pena
Abstract
Extracorporeal membrane oxygenation successfully supports critically ill patients. Despite hemorrhagic complications, systemic anticoagulation is required during ECMO support to avoid circuit clotting. Nitric Oxide (NO) surface anticoagulation has been proposed as an alternative local anticoagulation strategy. In this study, we aim to measure and evaluate the toxicity of NO in an ovine ECMO model. Methods: Eight sheep (40-50 kg) were anesthetized and instrumented for ECMO vascular access via the right internal jugular vein (drainage) and the right femoral vein (reinfusion). An arterial line was placed for hemodynamic monitoring. Four groups (n=2) with different ECMO circuits without systemic anticoagulation were studied: 1) Naïve uncoated circuit; 2) Carbosil coated circuit; 3) NO-releasing circuit +100 ppm NO sweep; and 4) NO-releasing circuit +200 ppm NO sweep. All animals remained under anesthesia until completion of the study (24hr) or circuit clotting. Data collected included: heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), P/F Ratio, and systemic vascular resistance (SVR). Methemoglobin (MetHb) levels to assess NO toxicity (>5%) with or without clinical signs. Results: Four sheep (50%) completed the 24hr study [group 1 (2), group 3 (1), and group 4 (1)]. The other animals were terminated earlier due to circuit clotting. MetHb was 1-1.9% within normal physiological values, and no signs of methemoglobinemia were observed. However, the NO-releasing groups had higher MetHb levels [group 3 (1.6%) and group 4 (1.9%)]. HR, MAP, and SVR were maintained between normal ranges in all groups. However, MAP and SVR in the NO-releasing groups were lower without clinical impact due to NO vasodilatory effect. Conclusion: There is no evidence of acute NO toxicity within the first 24hr of ECMO support when NO-releasing circuits are used at 100 and 200 ppm sweep gas flow. Further investigation as to long-term toxicity is warranted.
