Peripheral Blood Flow in the Neonate. 1. Changes in Total, Skin, and Muscle Blood Flow with Gestational and Postnatal Age

Abstract

Summary MATERlALS AND METHODSTotal peripheral blood flow and blood flow through the skin and A group of 62 newborn infants with birth weights ~3500 g who muscle were measured in the calf with an electrocapacitance were clinically well were selected for blood flow measurements. plethysmograph with counter pressure in a group of 62 "well" Total peripheral blood flow and blood flow through the skin and newborn infants (birth weight, ~3 5 0 0 g). Blood pressure in the muscle were measured in the calf with an electrocapacitance contralateral leg was measured with an Arteriosonde 1010, and plethysmograph with local counterpressure as described by Hyperipheral vascular resistance was calculated as mean blood pres-man et al. (9,10). Modifications were made in the size of the sure (mm Hg) divided by blood flow (ml per 100 ml tissue per min). pressure cuffs in the arterial, venous, and counterpressure systemThe results show that total peripheral blood flow and blood flow to adapt it for use in the premature infant as described previously through the skin and muscle correlated inversely with increasing by Wu et al. (21). The infants were placed in an incubator with birth weight and gestational age. Postnatally, total blood flow and servo control (model. Isolette-C86) to maintain abdominal skin blood flow through the skin and muscle decreased gradually during temperature at 36.5OC. Contralateral calf skin temperature was the first 7 days of life and in the rest of the neonatal period. measured with a Yellow Spring thermometer. Blood flow meaPeripheral vascular resistance and resistance in the skin and surements were made with infant at "rest" 0.5 to 1.5 hr after a muscle correlated directly with increasing birth weight and gesta-feed (21). tional age. Postnatally, peripheral vascular resistance and resistBlood pressure in the contralateral leg was measured with an ance in the skin and muscle increased during the first 7 days of Arteriosonde 1010 Ultrasonic Blood Pressure machine just before life and the neonatal period.the blood flow measurements. Peripheral vascular resistance was expressed in "resistance units" and calculated as mean blood Speculation pressure (mm Hg) divided by blood flow (ml per 100 ml tissue per min). The lower peripheral vascular resistance and h~p e~a s c u l a r i t~ Daily measurements were made during the first wk of life. In in the skin of immature infants account for higher peripheral blood addition, 18 infants (mean birth weight, 1450.3 * 178.9 6; mean flow in these infants. The associated increment in peripheral gestational age, 32 * 1.9 wk) were followed at weekly intervals to vascular resistance account for the gradual decrement in periph-determine changes in blood flow with postnatal age. era1 blood flow with advancing maturity and postnatal age. Differences in change of total peripheral blood flow and blood flow in STATlSTICAL METHODOLOGY the skin and muscle in relation to change in state, environment, and biochemical alterations need to be studied.The data were analyzed on the University o...

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