Intratracheal administration of a perfluorocarbon liquid (perfluorooctyl bromide, PFOB) during continuous positive-pressure ventilation (partial liquid ventilation, PLV) improves lung function in animals with lung injury. We attempted to determine whether there is a correlation between improvement of oxygenation and distribution of PFOB in a rabbit lung injury model using
1H and
19F nuclear magnetic resonance imaging.
Oleic acid was administered intravenously at 0.1m
l·kg
-1 to induce lung injury in six anesthetized rabbits ventilated at F
IO
2 1.0. After baseline blood gas analysis, 45m
l of PFOB was given intratracheally and the blood gas was analyzed every 30min thereafter. Postmortem
1H and
19F magnetic resonance imaging (MRI) was conducted using a 4.7-T, 33cm horizontal bore Varian NMR (nuclear magnetic resonance) spectroscopy/imaging system. Seven slices of both
1H and
19F lung images were obtained using the FLASH (fast low angle shot) method. Improvement of oxygenation was calculated by subtracting the baseline PaO
2 from the PaO
2 (mmHg) at 30min after PLV. Distribution of PFOB was calculated by dividing the sum of PFOB areas of seven lung slices using
19F imaging by the sum of the lung areas in the same slices using
1H imaging.
Fluorothorax developed in one animal and PaO
2 did not improve. This animal was therefore excluded from further analysis. PaO
2 improved from 66±23mmHg (mean±SD) at the baseline to 159±91mmHg at 30min after PLV. PFOB was distributed in 54±29% of the lung area in five animals. It was distributed mainly in the dependent lung region, probably because of its high specific gravity (1.92 at 25°C). There was no correlation (r
2=0.60,
P>0.05) between the improvement of oxygenation and the distribution area of PFOB. It was suggested that reexpansion of dependent lung alveoli by PFOB might be one of the beneficial effects of PLV.
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