INHALED NITRIC OXIDE DOES NOT ADVERSELY AFFECT LUNG MECHANICS IN EXPERIMENTAL RESPIRATORY DISTRESS SYNDROME. 2054

Abstract

We previously reported brief (30 minutes) administration of inhaled nitric oxide (INO) to premature lambs resulted in worse tidal volume and dynamic compliance. To determine if this effect is sustained, we measured lung mechanics in premature lambs randomized to receive either INO or control gas for four hours. We studied eight sets of premature lamb twins (119 - 126 days gestation, ≅ 0.8 term). Arterial and venous catheters, and tracheal tubes were placed and modified natural surfactant (beractant) was given prior to mechanical ventilation. Lambs were delivered, stabilized and mechanically ventilated for approximately two hours prior to baseline pulmonary function measurements. One twin was randomly assigned to receive 20 ppm INO while the other received control gas (Control) for the next four hours. Pulmonary function measurements (dynamic compliance (Cdyn), respiratory system compliance (Crs), inspiratory tidal volume (VTi), and respiratory system resistance (Rrs)) were made hourly (SensorMedics 2600). One lamb died before entry into the study. There were no significant differences in the pulmonary function measurements between the INO and Control groups. Data in table are mean ± SE at baseline and four hours. We conclude that four hour administration of INO does not adversely affect lung mechanics in preterm lambs with experimental respiratory distress syndrome. We speculate that INO may be used in premature infants without compromising lung mechanical function.