Transpulmonary driving pressure during mechanical ventilation-validation of a non-invasive measurement method

Background Transpulmonary driving pressure plays an important role in today's understanding of ventilator induced lung injury. We have previously validated a novel non-invasive method based on stepwise increments of PEEP to assess transpulmonary driving pressure in anaesthetised patients with healthy lungs. The aim of this study was to validate the method in patients who were mechanically ventilated for different diagnoses requiring intensive care. Methods We measured transpulmonary pressure (Ptp) and calculated transpulmonary driving pressure (Delta Ptp) in 31 patients undergoing mechanical ventilation in an intensive care unit. Parallel triplicate measurements were performed with the PEEP step method (PtpPSM) and the conventional oesophageal balloon method (Ptpconv). Their agreement was compared using the intraclass correlation coefficient (ICC) and the Bland Altman plot. Result The coefficient of variation for the repeated measurements was 4,3 for Delta PtpPSM and 9,2 for Delta Ptpconv. The ICC of 0,864 and the Bland Altman plot indicate good agreement between the two methods. Conclusion The non-invasive method can be applied in mechanically ventilated patients to measure transpulmonary driving pressure with good repeatability and accuracy comparable to the traditional oesophageal balloon method.