Mathematical Modelling of Carbon Dioxide Exchange in Hollow Fiber Membrane Oxygenator

The main objective of this study is to simulate the carbon dioxide (CO₂) blood-gas exchange in membrane oxygenator, evaluate the effect of sweep gas flow rate on CO₂ partial pressure (pCO₂) and to determine the response of pCO₂ to the step change of sweep gas flow rate. In extension to the simulation of gas transfer in membrane oxygenator, open-loop response on sweep gas flow rate was applied to the developed mathematical model to prove its effect on CO₂ removal rate. Three sweep gas flow rates were set, i.e. 1 L/min (Qg/Qb = 0.5), 2 L/min (Qg/Qb = 1) and 4 L/min (Qg/Qb = 2) and the simulated pCO₂ in artery was observed. Next, one-way ANOVA test was performed to determine the significant difference in CO₂ removal rate between these gas flow rates. For the next test, sweep gas flow rate was changed at t = 60 second and t = 120 second of simulation, to evaluate how pCO₂ will response to the step change of gas flow rate. As the result, the highest CO₂ removal observed when Qg/Qb = 2, as compared to gas-blood ratio of 1 and 0.5. The ANOVA test also proved the significant difference in simulated pCO2 for each flow rate. For the last test, a proportional response of pCO₂ towards the change of sweep gas flow rate was highlighted. In conclusion, the rate of CO₂ removal from blood can be manipulated by sweep gas flow rate and this rate can be adjusted to achieve the optimum performance of membrane oxygenator for CO₂ sequestration. (paper)