Figure 4.

Effect of discontinuation of ENO and NO in a piglet model of lung injury. Pulmonary hypertension was induced in intubated neonatal pigs breathing 100% oxygen by repeated saline lavage. Either NO (20 ppm followed by 5 ppm), or ENO (≈5–10 ppm), or nothing (Control, i.e., values after lung injury) was then added to the inhaled gas for 2 hr. (Dosing was designed to achieve comparable reductions in PVR.) Control animals showed a progressive rise in PVR (61%) and fall in CO (40%) over the 2-hr period that followed injury; and accordingly, PAP remained essentially unchanged (±8%). (A) A-a O₂ ratio; the mean PaO₂ is also shown; (B) PVR; (C) PAP; (D) fall in CO (compared with baseline, i.e., values before injury). Hemodynamics were measured every 5 min for 20 min after abrupt discontinuation of inhaled gases (post). *, P < 0.05 and #, P = 0.06, compared with control.