Nick Patel
Research Mentor: Alvaro Rojas-Peña
Mentor Department: Department of Surgery-Transplantation, Medicine
Author(s): Nick Patel, Spencer Amacher, Joanne Jung, Daniela Pelaez-Palacio, Ryan Kauffman, Jianfeng Wu, Orsolya Lautner-Csorba, Joseph Potkay, Alvaro Rojas-Peña
Session: Session 5 (2:00 PM – 2:50 PM)
Presentation Type: Poster 45
Abstract
Bacteremia during extracorporeal life support (ECLS) carries >50% mortality, highlighting the need for strategies to reduce bacterial load. We used an in vitro ECLS circuit to test two nitric oxide (NO)-based interventions: 1) NO (30 ppm) supplementation in the sweep gas; and 2) dibutylhexyldiamine diazeniumdiolate (DBHD) a NO-donor applied to argatroban-coated circuit tubing. Methods: A simulated ECLS circuit was constructed using a pediatric FX05 reservoir and oxygenator with perfusate consisting of 1:1 packed red blood cells and plasma. Circuits were maintained at 37°C and inoculated with 10^6 CFU/mL each of methicillin-resistant S. aureus (MRSA) and P. aeruginosa. Three conditions were tested: controls (n=7), 30 ppm NO in sweep gas (n=3), and DBHD+argatroban-coated tubing (n=5). Blood samples were collected at 0, 6, and 12 hours for bacterial culture and FMetHb was monitored via arterial blood gasses. Results: Control circuits showed bacterial growth over 12 hours, with mean plate counts increasing from 4.24 to 4.79 log CFU/mL (+411% from baseline). In contrast, 30 ppm NO in sweep gas reduced bacterial load from 4.23 to 3.86 log CFU/mL (-37% from baseline). DBHD+argatroban-coated circuits reduced bacterial load from 3.94 to 3.44 log10 CFU/mL (-54% from baseline). Repeated-measures ANOVA showed a significant group effect (p<0.001) and group by time interaction (p = 0.005). Post-hoc testing demonstrated a significantly lower bacterial burden in DBHD versus control at 6 hours (p<0.001) and 12 hours (p<0.001), and in NO sweep versus control at 12 hours (p<0.05). Methemoglobin remained low in controls and DBHD circuits, but was elevated in the NO sweep group, reaching approximately 9.25% at 12 hours. Conclusion: Both NO in sweep gas and NO-releasing coated tubing significantly reduced bacterial burden in an in vitro ECLS bacteremia model, providing proof of concept for NObased antimicrobial strategies during ECLS. These strategies may serve as adjuncts to reduce infection-related morbidity in ECLS patients and warrant further investigation.
