Cerebral blood flow and sleep state in the normal newborn infant.

The cerebral blood flow (CBF) index measured by venous occlusion plethysmography in 12 normal newborn infants was found to vary significantly with sleep state. Criteria for definition of sleep state are described. The cerebral blood flow index in active sleep was 23% higher than in quiet sleep, and there were smaller, but consistent and significant, differences between intermediate and active or quiet sleep.     

Effect of feeding on jugular venous blood flow in the normal newborn infant.

Jugular venous occlusion plethysmography was used to measure jugular blood flow in 47 infants; this was done at varying times after the end of a feed. Jugular blood flow was found to be lower, by about 30%, during the first postprandial half hour than at any other time up to 2 hours postprandially. In 2 infants longitudinal studies were performed in relation to several feeds, and postprandial reductions in blood flow of a similar magnitude were found. Aspects of the venous occlusion technique are discussed. It is concluded that feeding in healthy neonates is associated with a subsequent reduction in jugular blood flow, and possible mechanisms for this phenomenon are discussed.     

Aural temperature of the newborn infant.

The aural, oesophageal, and rectal temperatures of 10 term infants were monitored during changes in environmental temperature. The aural temperature in normal infants was found to be consistently higher than at any other site. It is suggested that this finding is due to the local heating effect of brain metabolism and shows the important contribution to total body heat production made by the brain. The depressed aural temperature found in an infant with hydranencephaly is cited as supporting evidence and may indicate the potential of aural temperature measurement in the investigation of cerebral metabolism.