TY - JOUR T1 - Prone position improves expiratory airway mechanics in severe chronic bronchitis JF - European Respiratory Journal JO - Eur Respir J SP - 259 LP - 268 DO - 10.1183/09031936.05.00094704 VL - 25 IS - 2 AU - S. D. Mentzelopoulos AU - C. Roussos AU - S. G. Zakynthinos Y1 - 2005/02/01 UR - http://erj.ersjournals.com/content/25/2/259.abstract N2 - Based on lung parenchyma-airways' interdependence, the present authors hypothesised that prone positioning may reduce airway resistance in severe chronic bronchitis. A total of 10 anaesthetised/mechanically ventilated patients were enrolled. Partitioned respiratory system (RS) mechanics during iso-flow experiments (flow = 0.91 L·s−1, tidal volume (VT) varied within 0.2–1.2 L), haemodynamics, gas-exchange, expiratory airway resistance (Raw,exp), functional residual capacity (FRC), change in FRC (ΔFRC), end-expiratory lung volume (EELV), expiratory airway resistance at EELV (Raw,exp,EELV), intrinsic positive end-expiratory pressure (PEEPi), and mean end-expiratory flow were determined in baseline semirecumbent (SRBAS), prone, and post-prone semirecumbent (SRPP) postures. Pronation versus SRBAS resulted in significantly reduced Raw,exp (at VT ≥0.8 L), Raw,exp,EELV (18.3±1.4 versus 31.6±2.6 cm H2O·L−1·s−1), inspiratory airway resistance (at VT ≥1.0 L), static lung elastance (at VT ≤0.6 L), “additional” RS/lung resistance (at a range of VTs), ΔFRC (0.35±0.03 versus 0.47±0.03 L), EELV (4.92±0.49 versus 5.65±0.65 L), RS/lung PEEPi (6.7±1.1/5.4±0.6 versus 8.9±1.7/7.8±1.1 cm H2O), mean end-expiratory flow (63.9±4.2 versus 47.9±4.0 mL·s−1), and shunt fraction (0.16±0.03 versus 0.21±0.03); benefits were reversed in SRPP. In severe chronic bronchitis, prone positioning reduces airway resistance and dynamic hyperinflation. ER -