Background: Selecting positive end-expiratory pressure (PEEP) during mechanical ventilation is important, as it can influence disease progression and outcome of acute respiratory distress syndrome (ARDS) patients. However, there are no well-established methods for optimizing PEEP selection due to the heterogeneity of ARDS. This research investigates the viability of titrating PEEP to minimum elastance for mechanically ventilated ARDS patients. Methods: Ten mechanically ventilated ARDS patients from the Christchurch Hospital Intensive Care Unit were included in this study. Each patient underwent a stepwise PEEP recruitment manoeuvre. Airway pressure and flow data were recorded using a pneumotachometer. Patient-specific respiratory elastance (E rs ) and dynamic functional residual capacity (dFRC) at each PEEP level were calculated and compared. Optimal PEEP for each patient was identified by finding the minima of the PEEP-E rs profile. Results: Median E rs and dFRC over all patients and PEEP values were 32.2 cmH2O/l [interquartile range (IQR) 25.0-45.9] and 0.42 l [IQR 0.11-0.87]. These wide ranges reflect patient heterogeneity and variable response to PEEP. The level of PEEP associated with minimum E rs corresponds to a high change of functional residual capacity, representing the balance between recruitment and minimizing the risk of overdistension. Conclusions: Monitoring patient-specific E rs can provide clinical insight to patient-specific condition and response to PEEP settings. The level of PEEP associated with minimum-E rs can be identified for each patient using a stepwise PEEP recruitment manoeuvre. This 'minimum elastance PEEP' may represent a patient-specific optimal setting during mechanical ventilation.
- Dynamic functional residual capacity
- Mechanical ventilation
- Respiratory elastance