ADJUSTMENT OF VENTILATION AND PERFUSION IN THE FULL-TERM NORMAL AND DISTRESSED NEONATE AS DETERMINED BY URINARY ALVEOLAR NITROGEN GRADIENTS
A. N. Krauss M.D.1,
J. A. Soodalter B.A.1, and
P. A. M. Auld M.D.1
1 Department of Pediatrics, Cornell University Medical College, New York City
The urinary alveolar nitrogen gradient was measured serially in 20 normal and six distressed full-term newborn infants. When the gradient is small (less than 10 mm Hg) ventilation is evenly distributed throughout the lung. When a large gradient is determined this is a reflection of numbers of alveoli with low ventilation-perfusion (VA/Q) ratios. In healthy adults used as a control for the method, a gradient of less than 10 mm Hg was recorded. Healthy, nondistressed newborn infants were almost all within the normal range from the first day of life.
Infants found to have distress due to meconium aspiration or transient neonatal tachypnea had large gradients throughout the first week of life. The studies indicate that the healthy, full-term infant rapidly achieves a normal distribution of pulmonary ventilation, whereas serious maldistribution of ventilation occurs in meconium aspiration pneumonia.
Submitted on September 4, 1970
Accepted on December 4, 1970
