six hours after delivery, a 1200-g (2-lb 11-oz) newborn develops respiratory distress. she was born at 32 weeks' gestation. her pulse is 136/min, respirations are 60/min, and blood pressure is 60/30 mm hg. examination shows grunting and moderate intercostal and subcostal retractions. the lungs are clear to auscultation. umbilical artery blood gas analysis on 60% oxygen shows:
