RT Journal Article SR Electronic T1 Automatic tailoring of positive end-expiratory pressure (PEEP) by forced oscillation technique (FOT) during non-invasive ventilation: Effects of posture and exertion in COPD JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P2063 VO 40 IS Suppl 56 A1 Raffaele Dellaca A1 Bob Romano A1 Joe Garuccio A1 Cherian John A1 Ramesh Thimmiah A1 Melvin Saludes A1 Charles Cain YR 2012 UL http://erj.ersjournals.com/content/40/Suppl_56/P2063.abstract AB Expiratory Flow Limitation (EFL) promotes the development of intrinsic PEEP (PEEPi). EFL can be detected by FOT at 5 Hz from the difference between inspiratory and expiratory reactance (ΔXrs) during quiet breathing (ERJ 2004;23:232) and CPAP (ERJ 2006;27: 983). This non-invasive measurement has been incorporated in a mechanical ventilator (Synchrony, Philips/Respironics, USA) resulting in a prototype that continuously measures ΔXrs and automatically adjusts PEEP to the minimum pressure able to abolish EFL (PEEPopt).The aim of this study was to measure PEEPopt in a group of COPD patients and to evaluate its alterations with changes in posture and during a six minute walking test (6MWT).Eleven COPD patients (GOLD stage 2-4, BMI 30±10, FEV1%pred 48±12, FEV1/FVC 56±8) were initiated to nasal BiPAP with automatic PEEP adjustment. After adaptation, ventilation was applied for 10 minutes in the seated and supine positions and during a 6MWT. Data were recorded in the last minute for each condition.At PEEP=2cmH2O, 8 patients showed EFL in the seated position, 10 in the supine and 9 in the last minute of the 6MWT. The average PEEPopt is reported in figure.In mild to severe COPD, the development of EFL is greatly affected by posture and exertion and this results in major adjustments in the PEEP required to counteract PEEPi within the same patient.