Observations on blood pressure in newborn infants

Abstract

An apparatus which automatically records blood pressure at 2-minute intervals in babies is described. The fluctuations and rhythms in a baby's blood pressure are demonstrated. Although there is no circadian rhythm in babies, there is a rhythm related to feeds. Feeding itself causes a large rise in blood pressure and the reasons for this rise are analysed. Direct arterial blood pressure readings from a number of babies are reported and analysed according to weight, gestation, and clinical condition. In 'small for dates' babies, the blood pressure is more closely related to the size of the baby than to his gestational age. The efficiency of external cardiac massage in producing a pulse pressure is demonstrated. The general contention that vasomotor regulatory mechanisms are functioning in babies is supported.