This study evaluated the effects of intranasal phenylephrine, an alpha-adrenergic agonist used for respiratory congestion, on uteroplacental blood flow. Twelve subjects were recruited from the Women's Clinic. Inclusion criteria were age greater than 18 years, singleton gestation, absence of medical illness and gestational age of 22-38 weeks. Phenylephrine (0.2 ml of 1% aq. solution) was applied to each nostril. Maternal blood pressure and pulse, umbilical artery velocimetry, and fetal heart rate were recorded prior to drug administration and at 5, 15, 30, 45 and 60 min after administration. There were no significant changes in maternal pulse, blood pressure or fetal heart rate. All subjects had normal baseline umbilical artery Doppler systolic/diastolic ratios. Eleven of 12 subjects demonstrated an elevation of the systolic/diastolic ratio consistent with vasoconstriction following administration. This elevation reached statistical significance at 30 min. Significant individual variation existed with regards to timing of maximal excursion of the systolic/diastolic ratio. The mean maximal change of the systolic/diastolic ratio was 1.57 +/- 1.25 (p < 0.001) ranging from -0.53 to 4.11. The use of over-the-counter alpha-adrenergic agents may result in decreased umbilical artery flow velocities. In high-risk pregnancies these medications may be contraindicated.
Background: Perinatal stroke is a common disorder in neonates with unknown etiology. Previous studies have linked anatomic variations in the Circle of Willis to adult stroke. This study aimed to understand the potential relationship between circle anatomy and common forms of perinatal stroke: NAIS, APPIS, and PVI. Methods: 94 subjects (62 NAIS/APPIS, and 32 PVI) were identifi ed from the Alberta Perinatal Stroke Project. Inclusion criteria were: MRI-confi rmed perinatal stroke, 3D-TOF MRA, and absence of other disorders. Images were classifi ed as complete, incomplete posterior circulation, incomplete anterior circulation, and incomplete anterior and posterior circulation. Fisher Exact Test compared completeness against stroke type and segment absence ipsilateral to stroke. Mann-Whitney U compared completeness and lesion volume. Results: Completeness was more common in PVI than NAIS/ APPIS (p=0.500) and in healthy controls than total stroke population (p=0.251). Ipsilesional absent segments were more frequent in NAIS/APPIS (p= 0.270). NAIS/APPIS patients with complete CoW had larger median lesion volume was compared to those with incomplete circles (p=0.484), with contralateral absence (p=0.943), and with ipsilateral absence (p=1.00). The opposite was found in PVI patients for all lesion volume comparisons (p=0.321, 0.362, 0.739 respectively). Conclusions: Circle anatomy is highly variable in perinatal stroke. Absence of segments is not associated with stroke type, lesion side, and lesion volume.
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