Opposing Forces to Breathing in Newborn Infants

Abstract

The mean opposing pressures to breathing in newborn infants were calculated from measurements of the elastic recoil and the flow resistance of various parts of the respiratory system. Comparison of newborn values with those in adults led to the following conclusions: the mean opposing elastic pressure and the resistive pressures of the lung are similar in newborns and adults; the largest single pressure components in both groups is due to the elastic recoil of the lung; newborns can maintain a relatively larger minute ventilation than adults without applying a larger resistive pressure; in newborns the opposing pressure offered by nasal airway resistance is smaller but that due to lung tissue resistance is relatively larger than in adults. The relative magnitude of the different opposing pressures and other mechanical characteristics of the respiratory system provide a better understanding of the pattern of breathing in the normal newborn and the changes occuring in various pathological conditions.