title: Esophageal pressure as an estimate of average pleural pressure with lung or chest distortion in rats.
abstract: Pressure-volume curves of the lungs and chest wall require knowledge of an effective 'average' pleural pressure (Pplav), and are usually estimated using esophageal pressure as Ples-V and Pwes-V curves. Such estimates could be misleading when Ppl becomes spatially non-uniform with lung lavage or shape distortion of the chest. We therefore measured Ples-V and Pwes-V curves in conditions causing spatial non-uniformity of Ppl in rats. Ples-V curves of normal lungs were unchanged by chest removal. Lung lavage depressed PLes-V but not Pwes-V curves to lower volumes, and chest removal after lavage increased volumes at PL≥15cmH2O by relieving distortion of the mechanically heterogeneous lungs. Chest wall distortion by ribcage compression or abdominal distension depressed Pwes-V curves and Ples-V curves of normal lungs only at Pl≥3cmH2O. In conclusion, Pes reflects Pplav with normal and mechanically heterogeneous lungs. With chest wall distortion and dependent deformation of the normal lung, changes of Ples-V curves are qualitatively consistent with greater work of inflation.
authors: Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università di Milano, Milan, Italy.
authors: Matteo
authors: M
authors: Pecchiari
authors: Stephen H
authors: SH
authors: Loring
authors: Edgardo
authors: E
authors: D'Angelo
mesh_terms: D000818:Animals; D004947:Esophagus / Q000502:physiology*; D008168:Lung / Q000502:physiology; D008176:Lung Volume Measurements; D008297:Male; D010994:Pleura / Q000502:physiology*; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D015656:Respiratory Mechanics / Q000502:physiology*; D035441:Thoracic Wall / Q000502:physiology