A COMPARISON OF INTRATRACHEAL AND INTRAVENOUS ADMINISTRATION OF GENTAMICIN DURING LIQUID VENTILATION

Pulmonary absorption of aminoglycosides is poor with intravenous admin istration, but may be enhanced by direct intratracheal administration of these drugs using perfluorochemical liquid ventilation (LV). To tes t this hypothesis, gentamicin sulfate was administered to two groups o f newborn lambs during LV. Serum and lung tissue levels of gentamicin were compared after either pulmonary intratracheal (IT) or intravenous (IV) routes of administration. Serial serum levels of gentamicin were obtained every 15 min for the 1st h, every 30 min for the 2nd h, and then hourly until sacrifice (maximum 6 h). At sacrifice, representativ e samples of each lung lobe were homogenized and analyzed for tissue g entamicin content. At 1 h, serum gentamicin levels were similar in bot h groups: IT administration levels were 3.7 +/- 0.55 SE mu g/ml and IV levels were 3.5 +/- 0.85 SE mu g/ml. The peak serum gentamicin level of 4.8 +/- 0.8 SE mu g/ml for the pulmonary administration group occur red 1.5 h after administration. Lung tissue levels of gentamicin for I T administration (4.04 +/- 0.62 SE mu g/g) were significantly greater than for IV administration (1.75 +/- 0.33 SE mu g/g; P < 0.05). There were no significant differences in interlobar gentamicin distribution for either mode of administration. Conclusion Perfluorochemical can be used as a vehicle for intratracheal delivery of antimicrobials. This route provides equivalent serum levels at 1 h, higher lung tissue leve ls, and uniform interlobar distribution relative to intravenous admini stration of gentamicin. We speculate that pulmonary administered genta micin during LV may provide an effective alternative treatment modalit y in the management of severe neonatal pneumonia.