We hypothesized that instillation of PGI2 in a liquid perfluorochemical during PLV may improve upon the alternative methods of systemic or neubulized deliveries of PGI2, for the treatment of PHT. Piglets (2-3 weeks of age) were randomized to conventional ventilation (IPPV) or PLV (initial perfluorocarbon volume 25-30 ml/kg; Rimar 101 O). A thromboxane (TX) mimetic (U46,619:0.06 μg/kg/min) was intravenouly administered to raise mean pulmonary artery pressure (Ppa) >35 torr. Thereafter, during IPPV, PGI2 (epoprostenol sodium, Flolanâ, GlaxoWellcome, NC) was administered by nebulization (20 μg/ml) (NEB) or intravenously (250 ng/kg/min)(IV) while during PLV, it was delivered through the distal port of a triple lumen endotracheal tube at a rate of 250 or 500 ng/kg/min. Blood gases, pulmonary vascular resistance (PVR), vascular pressures, and cardiac output (QT) were measured after each 30 minutes sequences. Data are presented as% of change from TX. Mean±s.e.m.*:≠ IV,NEB and ξ: ≠ PLV,IV; P <0.05 Table

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Although PGI2 administered through PLV effectively reduced PVR it also impaired oxygenation. We speculate that PLV may result in alveolar hypoxic vasoconstriction that was abolished by the local delivery of PGI2. Nebulized PGI2 may be a more optimal and safer method of treatment when PHT is not associated, with extensive parenchymal disease.