Robust Control of Oxygen Saturation During Mechanical Ventilation

Acute respiratory distress syndrome (ARDS) is a disease that has a high reported mortality rate. The treatment for ARDS typically involves mechanical ventilation that is tailored to each patient's needs. A crucial aspect of this treatment is maintaining adequate oxygen saturation of haemoglobin by setting the fraction of inspired oxygen. This paper proposes a design method of robust proportional-integral-derivative (PID) controllers using a gas exchange model during ARDS. Several PID controllers were synthesized for different sub-operational ranges defined by measurable quantities of the mechanical ventilator and the patient using a mixed sensitivity H∞ approach. In simulations, the controller demonstrated high robustness to external changes and changes in the patient's condition, with saturation always above 88%. Although further validation of the controller is required, the results indicate that the presented robust control method has the potential to be clinically relevant.