Whole body barometric plethysmography: a screening method to investigate airway reactivity and acute lung injuries in freely moving pigs

The aim of this work was to investigate whether the Penh index, measured using whoie body barometric piethysmography, can be used as a screening parameter to evaluate the airway reactivity and the intensity of the pulmonary response to endotoxins. Penh was firstly recorded in non-sedated freeiy moving piglets exposed (1) to a nebulized acetylchoiine (Ach) pre-treated or not with cienbuterol, or (2) to endotoxin challenge. To measure Penh simultaneously with total pulmonary resistance (RL), dynamic compliance (cd1) and intrapleural pressure changes (MaxPpl), an oesophageal balloon catheter technique was used and the piglets were anaesthetised. The recordings were performed during (1) an intravenous metacholine (Mch) challenge and (2) in endotoxin-exposed animais. In freely moving animais, Ach induced a significant dose-dependent increase in Penh, which was significantly blocked by clenbuterol. Endotoxin instillation aiso resulted in a significant rise in Penh while the corresponding response measured under anaesthesia was signiflcantly and positively correlated with RL and MaxzPpi. Similar results were obtained during Mch challenge but the Penh was negatively correlated with Cd. We conclude that Penh could be used in freely moving piglets as a screening index for airway reactivity and pulmonary functional changes in cholinergic and endotoxin challenge