| 1. |
- Gudmundsson, Saemundur, et al.
(författare)
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Factors affecting color Doppler energy ultrasound recordings in an in-vitro model
- 1998
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Ingår i: Ultrasound in Medicine and Biology. - 0301-5629. ; 24:6, s. 899-902
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Tidskriftsartikel (refereegranskat)abstract
- Compared to conventional color Doppler ultrasound imaging, the new color Doppler modality "color Doppler energy" (CDE) has improved the possibility of visualizing blood vessels having low blood-flow velocities, but appears to be influenced by the settings of the ultrasound instrument and motion artefacts. The aim of this methodological study was to evaluate the effects of the different factors on the CDE signal. The CDE mode of a commercially available ultrasound system (Acuson 128 XP) was tested in an in vitro study. The effect of depth, angle of insonation, flow velocity, instrument power output, gain and other instrument settings were evaluated. The CDE signals obtained were stored on videotape and subsequently subjected to off-line computer analysis. The CDE signal intensity was found to be influenced mainly by fluid flow velocity, but was also affected by depth and instrument settings. Gain and power had, however, limited influence in this setting. Thus, the intensity of the CDE signal is influenced by several factors. Our results emphasize the need for optimum fixed preinstalled instrument settings when attempting to quantify organ perfusion by use of this new technique.
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| 2. |
- Maesel, A, et al.
(författare)
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Mode of delivery and perinatal cerebral blood flow
- 1996
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Ingår i: Early Human Development. - 1872-6232. ; 44:3, s. 85-179
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To ascertain whether the perinatal cerebral blood flow velocity differed between vaginally delivered appropriate for gestational age (vag. AGA) term babies, AGA babies delivered by Caesarean section (C.s. AGA), and small for gestational age (C.s. SGA) babies also delivered by Caesarean section. STUDY DESIGN: Forty-five babies were examined by Doppler ultrasound of the middle cerebral artery prior to and immediately after delivery, and at 1 h and 24 h after birth. The pulsatility index (PI) and time-averaged maximum velocity (TAMXV) were calculated. RESULTS: No differences in TAMXV were found between the vag. AGA and C.s. AGA groups at any of the four recordings. A significantly higher PI value was found in the C.s. AGA group 1 h after birth. The C.s. SGA group had lower PI values before and just after birth, but did not differ significantly from the C.s. AGA group at 1 h or 24 h after birth. CONCLUSIONS: The results suggest mode of delivery to have a transitory effect on cerebral vascular resistance in healthy term AGA babies. The C.s. SGA group differed in the initial recording just after birth, but later manifested similar blood flow velocities in middle cerebral artery as the C.s. AGA group.
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| 3. |
- Pirhonen, J P, et al.
(författare)
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Frequency of anal sphincter rupture at delivery in Sweden and Finland--result of difference in manual help to the baby's head
- 1998
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 1600-0412 .- 0001-6349. ; 77:10, s. 974-977
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Anal sphincter rupture is a serious complication of vaginal delivery and almost half the affected women have persistent defecatory symptoms despite adequate primary repair. During the past decade, the incidence of anal sphincter ruptures has been increasing in Sweden and is currently estimated to occur in 2.5% of vaginal deliveries. The aim of the study was to report the frequency of anal sphincter ruptures in two university hospitals in two Scandinavian countries, Malmo in Sweden and Turku in Finland, and analyze the potential determinants. METHODS: Retrospective analysis of a population of 30,933 deliveries (26,541 vaginal) during the years 1990 to 1994. RESULTS: The incidence of anal sphincter ruptures in Malmo, Sweden was 2.69%, and in Turku, Finland 0.36%. There were no significant population differences for the known risk factors (fetal weight, nulliparity or fetal head circumference). However, there is a difference in manual support given to the perineum and to the baby's head when crowning through the vaginal introitus between Malmo and Turku. The proportion of operative vaginal deliveries and abnormal presentations was significantly higher in Turku reflected in the lower Apgar score at 5 minutes and longer duration of second phase of labor. When high risk deliveries (operative vaginal delivery, abnormal presentation and newborns over 4,000 g) were excluded, the risk for anal sphincter ruptures was estimated to be 13 times higher in Malmo than in Turku. CONCLUSIONS: The difference in the incidence of anal sphincter rupture between Malmo, Sweden and Turku, Finland may be due to the difference in manual control of the baby's head when crowning.
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