Year in review in Intensive Care Medicine 2009: II. Neurology, cardiovascular, experimental, pharmacology and sedation, communication and teaching

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Neural versus pneumatic control of pressure support in patients with chronic obstructive pulmonary diseases at different levels of positive end expiratory pressure: a physiological study

Intrinsic positive end-expiratory pressure (PEEPi) is a "threshold" load that must be overcome to trigger conventional pneumatically-controlled pressure support (PSP) in chronic obstructive pulmonary disease (COPD). Application of extrinsic PEEP (PEEPe) reduces trigger delays and mechanical inspiratory efforts. Using the diaphragm electrical activity (EAdi), neurally controlled pressure support (PSN) could hypothetically eliminate asynchrony and reduce mechanical inspiratory effort, hence substituting the need for PEEPe. The primary objective of this study was to show that PSN can reduce the need for PEEPe to improve patient-ventilator interaction and to reduce both the "pre-trigger" and "total inspiratory" neural and mechanical efforts in COPD patients with PEEPi. A secondary objective was to evaluate the impact of applying PSN on breathing pattern