Perfluorocarbon-associated gas exchange improves pulmonary mechanics, oxygenation, ventilation, and allows nitric oxide delivery in the hypoplastic lung congenital diaphragmatic hernia lamb model

OBJECTIVES To determine the efficacy of perfluorocarbon-associated gas exchange and the effects of inhaled nitric oxide during perfluorocarbon-associated gas exchange in the congenital diaphragmatic hernia lamb model. DESIGN Prospective, nonrandomized, controlled, nonhuman trial. SETTING Animal research facility. SUBJECTS Fetal lambs of 16 time-dated pregnant ewes, at 80 days gestation (term 140 to 145 days). MEASUREMENTS AND MAIN RESULTS The congenital diaphragmatic hernia lamb model was created in 16 animals. Twelve animals survived to be studied. All animals were mechanically ventilated for 4 hrs with a time-cycled, pressure-limited ventilator. Perfluorocarbon-associated gas exchange was started after 15 mins of ventilation (n equals 6). Blood gases were analyzed at 30 mins and then hourly. The perfluorocarbon-associated gas exchange animals had dynamic compliance and tidal volumes measured. After 1 hr, inhaled nitric oxide (80 parts per million) was delivered to the perfluorocarbon-associated gas exchange animals for 10 mins.All blood gas parameters, including pH (6.72 plus minus 0.06 vs. 7.14 plus minus 0.07), PCO2 (186 plus minus 12 vs. 70.5 plus minus 16.7 torr [24.8 plus minus 1.6 vs. 9.5 plus minus 2.1 kPa]), and PO2 (48 plus minus 17 vs. 156 plus minus 48 torr [6.4 plus minus 2.3 vs. 20.8 plus minus 6.4 kPa]) were significantly improved in the perfluorocarbon-associated gas exchange-treated group at 4 hrs (p less than .005). Dynamic compliance (0.13 plus minus 0.02 vs. 0.32 plus minus 0.06 mL/cm H2 O/kg) and tidal volume (3.5 plus minus 0.35 vs. 7.22 plus minus 0.61 mL/kg) were also significantly (p less than .001) increased in the perfluorocarbon-associated gas exchange group. In the perfluorocarbon-associated gas exchange animals, nitric oxide caused a significant (p less than .05) increase in oxygenation and a reduction in pulmonary hypertension. This effect was reversed by stopping the inhaled nitric oxide. CONCLUSIONS Perfluorocarbon-associated gas exchange significantly improved gas exchange, dynamic compliance, and tidal volumes. Furthermore, inhaled nitric oxide can be effectively delivered during perfluorocarbon-associated gas exchange to reduce pulmonary hypertension and enhance oxygenation.(Crit Care Med 1995; 23:1858-1863)