To access the changes of cerebral blood flow velocity according to the time after surfactant administration, we prospectively studied in the Hyaline Membrane Disease using Doppler ultrasonography.

The patients were 26 infants. The mean gestational age was 3l⁴wks (range, 18⁴ to 38wk). The ratio of male : female was 16 : 10, mean weight was 1.76±0.88Kg, Apgar score at 5min was 6.9, and type of delivery was C-section : vaginal delivery 19 : 4. Before and after, 10, 30min, 1, 6, l2hr, 1, 3, 5, 7days after surfactant administration, peak systolic and end-diastolic flow velocity(PSFV, EDFV) were estimated by Doppler method measuring MCA flow velocity. The Resistive index was calculated according to the mathematics. For the evaluation of the clinical status, systolic and diastolic systemic BP, PaO₂, PaCO₂, FiO₂, pH, and respiratory rate(RR) were checked.

The cerebral blood flow velocity showed initial increase of PSFV just after synthetic surfactant administration, and the increased PSFV continued until the 30 minites and then decreased. PSFV returns to initial level at 6hr, and then increased again. The changes of EDFV was not significant. The changes of RI & PI were no significant changes. The effects of surfactant to the systemic BP had no significance. The changes of PaCO₂ and PaO₂ were not significant. FiO₂ showed steady improvement. Initial tachypnea and acidosis progressively improved without clinical significance.

The administration of Surfactant in the HMD patients results in transient increase of cerebral blood flow velocity.