Control of skin blood flow in pre- and full-term infants.

The response of skin blood flow to local ischemia, heating and cooling was investigated at different intervals after birth in 10 healthy full-term babies and 10 preterm postincubator infants using 2 noninvasive and locally neutral methods of microcirculatory measurement: laser Doppler flowmetry and cutaneous oxygen partial pressure (cPO2) estimation with a probe temperature of 37 degrees C. Both groups of infants were capable of myogenic and neural control of skin blood flow. Higher cPO2 values under basal conditions and during reactive hyperemia suggest a raised nutritive capillary blood flow in the preterm group. The increase in cutaneous blood flow during local warming and reactive hyperemia shows that even in neonates on the first day of life no maximal skin vasodilatation is present. An increase in the periodic flow waves attributed to arteriolar vasomotion in 19- to 22-day-old infants, compared to the preterm group and younger babies, indicates that myogenic activity in skin arterioles increases with advancing age.