Closed-Loop Control of Arterial CO₂ in Mechanical Ventilation of Neonates

During mechanical ventilation of the neonate the main goal is to stabilize respiratory function of the often premature lungs. Ventilating the patient without inflicting harm is then the subordinated next goal. Ideally the arterial partial pressure of CO₂ lays within a normocapnic range and fluctuations are kept minimal. By closely monitoring CO₂ and controlling ventilation parameters accordingly, CO₂ levels in the blood can be managed. We present an approach consisting of a cascaded controller for arterial CO₂ by approximating arterial partial pressure PaCO₂ from end-tidal PetCO₂. As a proof of concept, feasibility of the controller was first evaluated on a mathematical patient model and subsequently in-vivo in lamb experiments. The controller is able to regulate CO₂ into a normocapnic range in both setups with satisfactory stationarity within the target range. Estimation of the arterial partial pressure of CO₂ remains a critical aspect that needs to be further investigated. Clinical relevance-Closed-loop control of CO2 in mechanical ventilation aims to avoid PaC O2 extremes and to reduce fluctuations. Both are a relevant risk factors especially for neurological complications among preterm newborns.