Airway surface liquid recovered by lavage with perfluorocarbon liquid in cats

Background Airway surface liquid (ASL) is difficult to sample. Lavage with an immiscible perfluorocarbon (PFC) liquid to recover ASL was evaluated in cats. Materials and Methods Six wild-type cats underwent bronchoscopic lavage with a PFC (perfluorohexane), with the bronchoscope wedged in the feline equivalent of the right lower lobe. Two cats (control animals) were lavaged with a saline vehicle only. Four procedures were performed on each animal at 2–3-week intervals. Ionic composition of ASL was determined by flame photometry. Results Cats lavaged with PFC showed significantly more acute respiratory distress than those lavaged with saline (respiratory rate following procedure: PFC, 47 ± 5 min−1 vs. saline, 27 ± 2 min−1, P   100 µL) which were sufficient for analysis. Mean (± SEM) ionic concentrations in these samples were Na+ 157·4 ± 14·5 mmol L−1, Cl− 150·5 ± 16·8 mmol L−1 and K+ 10·1 ± 1·7 mmol L−1. Conclusions Perfluorocarbon lavage can be used to collect unmodified ASL from the distal lung. However, repeated lavage with perfluorohexane was associated with significant pathological changes in this study.