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[Impaired postnatal cerebral perfusion after prenatal centralization-- increased risk of neonatal brain injury?]
E Robel-Tillig1, A Möckel, C Vogtmann
1Kinderklinik, Universität Leipzig.
Within the last years Doppler sonographic studies in high risk pregnancies had been included into obstetrical management strategies. Especially the high fetal risk in cases with severe intrauterine perfusion disturbances with signs of hemodynamic centralization--the brain sparing effect--had been established. In 11 premature newborns with prenatal sonographic recorded vasodilatation of cerebral vessels as a sign of hemodynamic centralization flow velocity waveforms of the anterior cerebral artery as well as left cardiac functional parameters (LVET, PEP) were measured at the 1st, 2nd, 3rd, 5th and 6th day of life. For the evaluation of the peripheral circulation the perfusion of the superior mesenteric artery was recorded by Doppler ultrasound. Additionally, the blood pressure, heart rate, pH and acid base status was considered. We used 25 premature newborns of corresponding gestational age and normal prenatal Doppler sonographic findings as a control group. In the group with prenatal brain sparing effect we could demonstrate a remarkable increase of the pulsatility index as a result of extreme diminished diastolic blood flow velocity. 5 newborns showed signs of reverse diastolic flow. The difference to the control group was highly significant. Perfusion measurements in the superior mesenteric artery demonstrated corresponding results at the first day of life with significant increased PI and diminished diastolic flow velocities. Our results demonstrate the great importance of prenatal diagnosis for the understanding of postnatal disturbances. The birth is not the endpoint of fetal hemodynamic centralization and the compensational mechanism is still continuing. Despite a well adapted cardiac function, normal hemodynamic situation and balanced metabolic findings remarkable changes of the impedance of the cerebral vessels are evident. Especially for the very immature newborns this may lead to the risk of leasions of the germinal matrix with following hemorrhage or ischaemic injury.
Within the last years Doppler sonographic studies in high risk pregnancies had been included into obstetrical management strategies. Especially the high fetal risk in cases with severe intrauterine perfusion disturbances with signs of hemodynamic centralization--the brain sparing effect--had been established. In 11 premature newborns with prenatal sonographic recorded vasodilatation of cerebral vessels as a sign of hemodynamic centralization flow velocity waveforms of the anterior cerebral artery as well as left cardiac functional parameters (LVET, PEP) were measured at the 1st, 2nd, 3rd, 5th and 6th day of life. For the evaluation of the peripheral circulation the perfusion of the superior mesenteric artery was recorded by Doppler ultrasound. Additionally, the blood pressure, heart rate, pH and acid base status was considered. We used 25 premature newborns of corresponding gestational age and normal prenatal Doppler sonographic findings as a control group. In the group with prenatal brain sparing effect we could demonstrate a remarkable increase of the pulsatility index as a result of extreme diminished diastolic blood flow velocity. 5 newborns showed signs of reverse diastolic flow. The difference to the control group was highly significant. Perfusion measurements in the superior mesenteric artery demonstrated corresponding results at the first day of life with significant increased PI and diminished diastolic flow velocities. Our results demonstrate the great importance of prenatal diagnosis for the understanding of postnatal disturbances. The birth is not the endpoint of fetal hemodynamic centralization and the compensational mechanism is still continuing. Despite a well adapted cardiac function, normal hemodynamic situation and balanced metabolic findings remarkable changes of the impedance of the cerebral vessels are evident. Especially for the very immature newborns this may lead to the risk of leasions of the germinal matrix with following hemorrhage or ischaemic injury.