OBJECTIVE To assess oesophageal Doppler ultrasonography as a convenient means of optimising positive end expiratory pressure for maximal delivery of oxygen to tissues. DESIGN Measurements of blood flow, arterial oxygen saturation, and cardiac output by thermodilution (when available) at baseline and at 20-30 minutes after each incremental increase (2.5-5.0 cm H2O) in positive and expiratory p...

Deviation of end-expiratory lung volume from the elastic equilibrium volume of the respiratory system is recognized as a cardinal feature in mechanically-ventilated patients with severe chronic obstructive pulmonary disease (COPD) and acute ventilatory failure (AVF). The presence of dynamic hyperinflation implies that alveolar pressure remains positive throughout expiration. At the end of the e...