Model-based optimal PEEP in mechanically ventilated ARDS patients in the Intensive Care Unit

Ten patients with acute lung injury or ARDS underwent incremental PEEP recruitment manoeuvres. PV data was measured at increments of 5 cmH2O and fitted to the recruitment model. Inspiratory and expiratory breath holds were performed to measure airway resistance and auto-PEEP. Three model-based metrics are used to optimise PEEP based on opening pressures, closing pressures and net recruitment. ARDS status was assessed by model parameters capturing recruitment and compliance.Median model fitting error across all patients for inflation and deflation was 2.8% and 1.02% respectively with all patients experiencing auto-PEEP. In all three metrics' cases, model-based optimal PEEP was higher than clinically selected PEEP. Two patients underwent multiple recruitment manoeuvres over time and model metrics reflected and tracked the state or their ARDS.For ARDS patients, the model-based method presented in this paper provides a unique, non-invasive method to select optimal patient-specific PEEP. In addition, the model has the capability to assess disease state over time using these same models and methods.Patients suffering from acute respiratory failure, such as Acute Respiratory Distress Syndrome (ARDS), are often admitted to the Intensive Care Unit (ICU) and require Mechanical Ventilation (MV). ARDS mortality rates range from 30% to 70% [1]. In ARDS, the lung is inflamed and filled with fluid, becoming stiff, and lung units can collapse from the weight of additional fluid reducing the number of functional units. Thus, the ARDS lung is a stiffer, smaller lung, the so called "baby lung" [2]. There are no specific treatments for acute respiratory diseases, except to facilitate an environment for patients to recover [3].Positive pressure ventilation has been highlighted as a key component of care [4,5], and is used to aid the recovery by reducing the work of breathing or taking over this work completely. Application of Positive End-Expiratory Pressure (PEEP) is one of the most im