Rishi Tappeta
Pronouns: He/Him
Research Mentor(s): Joseph Potkay
Research Mentor School/College/Department: VA Medical Center & UM Surgery / Medicine
Program:
Authors: Rishi Tappeta, Andrew Zhang, Brian Haimowitz, Qussai Dababna, Mai Doan, Joseph Potkay, Alvaro Rojas-Peña, Robert Bartlett
Session: Session 3: 11:00 am – 11: 50 am
Poster: 50
Abstract
Objective: Extracorporeal Membrane Oxygenation (ECMO) systems aid patients with severe respiratory failure. While wearable systems combined with physical therapy have great impacts on patient well-being, they are limited by respiratory fluctuation specifically in patient metabolism. To account for changing patient respiration rate, we have developed an ECMO system capable of responding to patient metabolism and oxygenating at a desired rate. Methods: A Novalung, sensor array, pump, and Artificial Lung (AL) make up the servoregulated system along with ?” tubing. Exhaust gas CO2 (EGCO2) partial pressure is used as an analog for partial arterial CO2 (PaCO2). An array of mass flow controllers modulates sweep gas through the AL in real-time to achieve a desired target EGCO2 (tEGCO2). To simulate changing metabolic rates, CO2 was pumped through the conditioning lung at intervals of 0.1 SLM, 0.2 SLM, and 0.4 SLM together with 2.0 L/min as a buffer gas. This was held until the system reached steady state. Performance at 0.8 SLM of CO2 was evaluated for some setpoints although this was limited to avoid damaging to the CDI-500. First, the performance of the servoregulated system under different tEGCO2s was assessed. The system was allowed to regulate sweep gas to meet tEGCO2 of 10mmHg, 20mmHg, 30mmHg, and 40mmHg at a blood flow rate of 1.0 L/min. For a control, the system was set at 1.0 SLM fixed sweep to simulate a normal ECMO system without smart feedback being operated by a physician. Second, the performance of the system under different blood flow rates was assessed. The flow rate was set to 0.5 L/min, 1.0 L/min, 2.0 L/min, and 4.0 L/min while tEGCO2 was fixed at 20mmHg. Two controls were used, one at 1.0 SLM fixed sweep, and one with a 1:1 blood:gas flow ratio. Results: When the system was challenged with changing blood pCO2 levels in in-vitro tests, it adjusted sweep gas to converge EGCO2 with tEGCO2 within 5 min. This capability was tested across multiple blood flow rates which correspond to changes in patient heart rate, and tEGCO2 levels which correspond with a higher respiratory rate . Controls with fixed sweep demonstrated higher EGCO2 levels when challenged with higher blood flow rates and higher blood pCO2 levels. Conclusions: This servoregulated system affords patients ease of life and preservation of dignity while concurrently facilitating physical therapy. It aids both patients and healthcare professionals in that it provides greater autonomy to patients while relieving healthcare professionals of urgence for surgery.
