Hemodynamic Safety Assurance in Closed-Loop Controlled Critical Care: Hemorrhage Resuscitation and Sedation Case Study

This letter presents a novel approach to assure hemodynamic safety in closed-loop controlled critical care. The approach is equipped with safety-preserving control based on control barrier functions to ensure the safety of hemodynamic state, hemodynamic monitoring to estimate hemodynamic state, and probabilistic recursive therapeutic target guidance to direct a patient as closely as possible to a prescribed therapeutic target along a desired trajectory. A notable advantage of the approach is that it can be augmented to single-input-single-output critical care control loops developed in isolation to guard hemodynamic safety against conflicts between them, providing a practical alternative to sophisticated multi-input-multi-output control loop design. The efficacy of the approach was examined in a hemorrhage resuscitation-intravenous sedation case study using realistic virtual patients. The approach as a whole assured the boundedness of hemodynamic state by reconciling conflicts between the two control loops. The recursive therapeutic target guidance directed patients to personalized reachable targets while maintaining the patients' therapeutic responses near the desired therapeutic trajectory. The approach may serve as an effective means to reconcile multiple critical care control loops and assure holistic hemodynamic safety.