TY - JOUR T1 - Validation of a method for non-invasive assessment of transdiaphragmatic pressure during support ventilation JF - European Respiratory Journal JO - Eur Respir J VL - 40 IS - Suppl 56 SP - 2851 AU - Kristel Lopez-Navas AU - Sebastian Brandt AU - Merle Strutz AU - Hartmut Gehring AU - Ullrich Wenkebach Y1 - 2012/09/01 UR - http://erj.ersjournals.com/content/40/Suppl_56/2851.abstract N2 - Especially during long term support ventilation continuous assessment of the patient's work of breathing can be helpful to improve the quality of the assistance. We designed the Occlusion+Delta (O+D) method to estimate non-invasively transdiaphragmatic pressure (Pdi) and started validation in a study with volunteers.Methods: Respiratory flow and airway pressure were recorded from 11 healthy men (21 to 68 years old) during quiet spontaneous breathing, increased effort and supported by a ventilator in ASB mode. Pdi was measured for control using a double-balloon catheter. Each 3 to 5 cycles our method was applied getting an estimation of respiratory resistance R and compliance C used to reproduce the Pdi of the coming cycles, which was compared to the measured Pdi by their inspiratory pressure time products (PTP).Results: The short occlusions required by O+D did not disturbed the volunteers and produced the expected signals. The obtained R (3.2 to 7.1cmH2O/l/s) and C (58.7 to 97.7ml/cmH2O) remained in the usual range for healthy adults. Regression and correlation analysis revealed high agreement between methods (PTPO+D = 1.00*PTPPdi-0.02, r=0.92, R2=0.86). The overall differences (n=2420 (220 per volunteer)) were 0.01±10.3cmH2O.s (mean±2SD).Conclusions: The results obtained demonstrate great potential in the developed method. A study with 30 volunteers is being carried out to complete validation. ER -