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Static pressure-volume curves and body posture in severe chronic bronchitis
S D Mentzelopoulos1, J Sigala, C Roussos
1Dept of Intensive Care Medicine, University of Athens Medical School, Evaggelismos Hospital, 45-47 Ipsilandou Str, GR 106 75, Athens, Greece.
The European Respiratory Journal
|April 14, 2006
Summary
Proning severely hyperinflated chronic bronchitis patients improves lung mechanics and gas exchange. This posture maximizes ventilation homogeneity and reduces arterial carbon dioxide levels, suggesting its utility in early mechanical ventilation.
Area of Science:
- Critical Care Medicine
- Respiratory Physiology
Background:
- Pronation has shown benefits in gas exchange and respiratory mechanics.
- Severely hyperinflated chronic bronchitis patients may experience maximal pronation benefits.
Purpose of the Study:
- To investigate pronation effects on gas exchange and respiratory mechanics in hyperinflated chronic bronchitis patients.
- To elucidate underlying mechanisms of pronation effects.
- To determine if pronation alters inspiratory pressure-volume (P-V) curve characteristics.
Main Methods:
- 16 mechanically ventilated patients with chronic bronchitis exacerbation were studied.
- Measurements included hemodynamics, respiratory mechanics, gas exchange, and lung volumes in semirecumbent (SREC), prone, and post-prone SREC postures.
- Static intrinsic positive end-expiratory pressure (PEEPi,rs) was >12 cmH2O; P-V curves were analyzed.
Main Results:
- Prone position reduced lower inflection point pressure by 20% and increased upper inflection point volume by 17% compared to pre-prone SREC.
- Improved lung mechanics, volumes, oxygenation, and arterial carbon dioxide tension (Pa,CO2) were observed.
- Postural decreases in PEEPi,rs and lung resistance predicted decreases in LIP pressure and Pa,CO2, respectively.
Conclusions:
- Pronation reduces lung lower inflection point pressure and increases upper inflection point volume in hyperinflated patients.
- Pronation maximizes effects on ventilation homogeneity and Pa,CO2.
- Pronation may be beneficial during early controlled mechanical ventilation.
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