Biomedical subjects

S A Scherjon

Publications and source records attributed to S A Scherjon.

22 records · Page 2Linked to original sources

PubMed1994

Effect of fetal brainsparing on the early neonatal cerebral circulation.

The effect of antenatal brainsparing on subsequent neonatal cerebral blood flow velocity (CBFV) was studied in very preterm infants. CBFV was determined, using a pulsed Doppler technique, both in the fetal and neonatal period. Neonatally, blood pressure and transcutaneous carbon dioxide tension (TcPCO2) was monitored simultaneously; daily cranial ultrasound examinations were performed. In infants with evidence of brainsparing a higher mean value of CBFV and a different pattern of changes of CBFV during the first week of life was demonstrated compared with infants with normal fetal cerebral haemodynamics. No differences were found in blood pressure and TcPCO2. The incidence of intracranial haemorrhages and of ischaemic echo-dense lesions was also the same for both groups. In a multivariate statistical model gestational age, antepartum brainsparing, and TcPCO2 all contributed significantly in explanation of variation in CBFV. It is speculated that a different setting of cerebral autoregulation related to differences in gestational age or to brainsparing might explain the difference in changes found in neonatal CBFV.

Blood Flow Velocity↗

PubMed1993

The "brain-sparing" effect: antenatal cerebral Doppler findings in relation to neurologic outcome in very preterm infants.

OBJECTIVE: Our purpose was to study the relationship between fetal cerebral circulation and neurologic outcome. STUDY DESIGN: In 117 high-risk fetuses (gestational age 25 to 33 weeks) flow velocity waveforms were recorded from the umbilical and medial cerebral arteries. The ratio between umbilical and cerebral pulsatility indexes was calculated. A ratio above a predefined tolerance limit was used as an index for the "brain-sparing" effect. Neonatal neurosonography and neurologic examination were used as outcome parameters. RESULTS: Antenatally raised ratios are associated with poor obstetric outcome (fetal death and fetal growth retardation). The incidence of intracranial hemorrhages and ischemic lesions was not different for infants with a normal or raised prenatal ratio. The incidence of neurologic abnormalities was the same for both ratio groups. CONCLUSIONS: The "brain-sparing" effect is a mechanism to prevent fetal brain hypoxia rather than a sign of impending brain damage.

Blood Flow Velocity↗

PubMed1993

Intra-observer and inter-observer reliability of the pulsatility index calculated from pulsed Doppler flow velocity waveforms in three fetal vessels.

OBJECTIVE: Study of the intra observer and inter observer reliability of the pulsatility index, calculated from pulsed Doppler recordings of three fetal vessels. DESIGN: Flow velocity waveforms (FVW) were recorded from the umbilical artery, the fetal descending aorta and the fetal internal carotid artery. Intra-observer reliability was assessed in six fetuses; ten repeated measurements were performed by one observer. Inter-observer reliability was studied in 14 fetuses; two observers performed two repeated measurements in each fetus. SETTING: A tertiary referral hospital. SUBJECTS: High risk pregnancies with a gestational age ranging from 29 to 42 weeks. MAIN OUTCOME MEASURES: Analysis of variance with repeated measurements and a graphical method were used for data analysis. Intra-observer repeatability was expressed as Intraclass Correlation Coefficient (IntraCC). Inter-observer agreement was expressed as Interclass Correlation Coefficient (InterCC). RESULTS: IntraCC for umbilical artery, descending aorta and internal carotid artery were 0.91, 0.78, and 0.54, respectively. InterCC values for these vessels were 0.39, 0.45 and 0.34, respectively. No systematic differences between the two observers except for the fetal descending aorta, were apparent. IntraCC decreased remarkable when fetuses with absent end diastolic velocities were excluded from the analysis. CONCLUSION: The pulsatility index (PI) used for fetal measurements has a poor reliability. This is of serious concern when clinical use of FVW measurements is considered as a diagnostic tool.

Aorta, Thoracic↗

PubMed1992

Fetal and neonatal cerebral circulation: a pulsed Doppler study.

We studied the relation between the fetal cerebral circulation and changes in the cerebral circulation directly after birth. With a combined real time ultrasound/pulsed Doppler technique flow velocity waveforms from the fetal umbilical- and carotid-circulation were monitored. Pulsatility Index (PI) was computed and the ratio between Umbilical PI and Carotid PI was calculated. Flow velocity waveforms of the cerebral circulation before birth were related to anterior cerebral artery flow velocity waveforms recorded immediately after birth. The study shows that changes in flow velocity waveforms associated with the intra uterine brain-sparing effect are related to poor obstetrical outcome. Furthermore is shown that the brain-sparing effect in the fetal period is associated with higher PI values in the cerebrovascular circulation in the neonatal period. It is suggested that changes in these PI values, representing changes in cerebrovascular resistance, might be indicative of cerebral ischemia in the neonate.

Carotid Arteries↗