Figure 2.

Airway and pulmonary artery smooth muscle area (mean and SD) in four preterm lambs that received iNO at 5–15 ppm (dark bars) compared with four preterm lambs that did not receive iNO (white bars) and four term lambs that did not receive iNO (hatched bars) during 3 weeks of mechanical ventilation. *Significant difference compared with the group of four preterm lambs not given iNO, p < 0.05; ^†significant difference compared with the group of four term lambs, p < 0.05.