ExtractTwenty infants with a clinical and radiologic diagnosis of hyaline membrane disease were studied serially by measurement of functional residual capacity (FRC) and arterial and alveolar gradients for O 2 , CO 2 , and N 2 . Nitrogen washouts were determined as well in nine infants.The FRC, alveolar-arterial O 2 gradients (AaD 02 ) in 100% O 2 , and true shunt (Q, s /Q,t), which are different ways of quantitating atelectasis and shunt in hyaline membrane disease, were shown to be statistically related. The FRC was below 1.0 ml/cm in all infants when sick and returned to the usual range for gestational age, generally around 15 days. Extensive cardiopulmonary shunting was recorded both at the height of illness and for a considerable time during recovery. However, during recovery, not all of the venous admixture was due to shunt. As maldistribution of ventilation was excluded, the possibility of a diffusion barrier was raised. Alveoli with a high VA/Q, were identified by large arterial-alveolar CO 2 gradients (aAD C o 2 ) both during illness and recovery. This indicates that maldistribution of pulmonary blood flow is an important physiologic abnormality in hyaline membrane disease.
Speculation
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.