Evaluation of lung recovery after static administration of three different perfluorocarbons in pigs.

International audienceBackground: The respiratory properties of perfluorocarbons (PFC) have been widely studied for liquid ventilation inhumans and animals. Several PFC were tested but their tolerance may depend on the species. Here, the effects of asingle administration of liquid PFC into pig lungs were assessed and compared. Three different PFC having distinctevaporative and spreading coefficient properties were evaluated (Perfluorooctyl bromide [PFOB], perfluorodecalin[PFD] and perfluoro-N-octane [PFOC]).Methods: Pigs were anesthetized and submitted to mechanical ventilation. They randomly received an intra-trachealadministration of 15 ml/kg of either PFOB, PFD or PFOC with 12 h of mechanical ventilation before awakening andweaning from ventilation. A Control group was submitted to mechanical ventilation with no PFC administration. Allanimals were followed during 4 days after the initial PFC administration to investigate gas exchanges and clinicalrecovery. They were ultimately euthanized for histological analyses and assessment of PFC residual concentrationswithin the lungs using dual nuclei fluorine and hydrogen Magnetic Resonance Imaging (MRI). Sixteen animals wereincluded (4/group).Results: In the PFD group, animals tended to be hypoxemic after awakening. In PFOB and PFOC groups, blood gaseswere not significantly different from the Control group after awakening. The poor tolerance of PFD was likely related toa large amount of residual PFC, as observed using MRI in all lung samples (≈10% of lung volume). This percentage waslower in the PFOB group (≈1%) but remained significantly greater than in the Control group. In the PFOC group, thepercentage of residual PFC was not significantly different from that of the Control group (≈0.1%). Histologically, themost striking feature was an alveolar infiltration with foam macrophages, especially in the groups treated by PFD orPFOB.Conclusions: Of the three tested perfluorocarbons, PFOC offered the best tolerance in terms of lung function, gasexchanges and residuum in the lung. PFOC was rapidly cleared from the lungs and virtually disappeared after 4 dayswhereas PFOB persisted at significant levels and led to foam macrophage infiltration. PFOC could be relevant for shortterm total liquid ventilation with a rapid weaning