Does the umbilical artery systolic/diastolic ratio reflect flow or acidosis?

Copel, Joshua A.; Schlafer, Donald H.; Wentworth, Richard A.; Belanger, Kathy; Kreitzer, Lois A.; Hobbins, John C.; Nathanielsz, Peter W.

doi:10.1016/0002-9378(90)91062-h

Cited by 27 publications

(9 citation statements)

References 11 publications

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“…In contrast with a previous study [11], we found no change in UAPI during spinal anaesthesia. Changes in previously normal umbilical artery waveform indices are generally associated with reductions in UPBF sufficient to cause fetal acidosis [19]. Thus the difference in UAPI results may reflect the lower UA pH in our earlier study.…”

Section: Discussionmentioning

confidence: 53%

Randomized trial of bolus phenylephrine or ephedrine for maintenance of arterial pressure during spinal anaesthesia for Caesarean section

Thomas¹,

Robson²,

Redfern³

et al. 1996

British Journal of Anaesthesia

163

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Thirty-eight healthy women undergoing elective Caesarean section under spinal anaesthesia at term were allocated randomly to receive boluses of either phenylephrine 100 micrograms or ephedrine 5 mg for maintenance of maternal arterial pressure. The indication for administration of vasopressor was a reduction in systolic pressure to < or = 90% of baseline values. Maternal arterial pressure (BP) and heart rate (HR) were measured every minute by automated oscillometry. Cardiac output (CO) was measured by cross-sectional and Doppler echocardiography before and after preloading with 1500 ml Ringer lactate solution and then every 2 min after administration of bupivacaine. Umbilical artery pulsatility index (PI) was measured using Doppler before and after spinal anaesthesia. The median (range) number of boluses of phenylephrine and ephedrine was similar; 6 (1-10) vs 4 (1-8) respectively. Maternal systolic BP and CO changes were similar in both groups, but the mean [95% CI] maximum percentage change in maternal HR was larger in the phenylephrine group (-28.5 [-24.2, -32.9]%) than in the ephedrine group (-14.4 [-10.6, -18.2]%). As a consequence atropine was required in 11/19 women in the phenylephrine group compared with 2/19 in the ephedrine group (P < 0.01). Mean umbilical artery pH [95% CI] was higher in the phenylephrine group (7.29 [7.28-7.30]) than in the ephedrine group (7.27 [7.25-7.28]). The results of the present study support the use of phenylephrine for maintenance of maternal arterial pressure during spinal anaesthesia for elective Caesarean section.

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Section: Discussionmentioning

confidence: 53%

Randomized trial of bolus phenylephrine or ephedrine for maintenance of arterial pressure during spinal anaesthesia for Caesarean section

Thomas¹,

Robson²,

Redfern³

et al. 1996

British Journal of Anaesthesia

163

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“…This study was designed to investigate fetuses with a moderate disturbance in fetoplacental hemodynamics. To identify these fetuses we could not use umbilical artery velocimetry as the sensitivity of this method in detecting mild to moderate disturbances has been questioned 25,26 . By selecting SGA fetuses with an estimated weight below −22% (−2 SD), where actually 20 of the 24 included fetuses had an estimated weight below −28%, there is still a risk that some fetuses were small owing to etiological factors other than placental insufficiency.…”

Section: Discussionmentioning

confidence: 99%

Central arterial hemodynamics in small‐for‐gestational‐age fetuses before and during maternal hyperoxygenation: a Doppler velocimetric study with particular attention to the aortic isthmus

Brantberg¹,

Sonesson²

1999

Ultrasound in Obstet & Gyne

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“…Experimental studies do, however, suggest that umbilical artery velocity wave form analysis is not sensitive enough to detect mild to moderate fetoplacental hemodynamic disturbances (3,4). A redistribution of fetal blood flow to maintain cerebral O2 delivery and consumption during hypoxemia and hypoxia has been demonstrated in animal models (5)(6)(7)(8)(9).…”

mentioning

confidence: 99%

Effects of Increased Resistance to Umbilical Blood Flow on Fetal Hemodynamic Changes Induced by Maternal Oxygen Administration: A Doppler Velocimetric Study on the Sheep

et al. 1993

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ABSTRACT. A fetal lamb model was used to investigate whether the effects of maternal O2 administration on fetal blood gases and hemodynamics were modified when the fetoplacental circulation was compromised by stepwise compression of both umbilical veins. At basal state, O2 administration increased O2 saturation (Sao2) and the pulsatility index (PI) of the carotid artery Doppler wave form ( p < 0.01). The first compression decreased left ventricular output (-21 + 16%, mean + 1 SD, p < 0.01) and umbilical mean velocity (-22 + 28%, p < 0.01) but did not modify carotid pH, Sao2, or the PI in any of the arteries studied. At this level of compression, O2 administration increased carotid Sao2 ( p < 0.01) but did not affect carotid PI. After a second compression, left ventricular output and umbilical mean velocity were even more reduced 1-39 f 21% ( p < 0.01) and -53 f 23% ( p < 0.01), respectively]. With this compression, carotid pH, Sao2, and PI decreased, whereas umbilical and descending aorta PI increased. O2 administration at this level of compression increased carotid Sao2 ( p < 0.01) but did not modify carotid PI.

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Does the umbilical artery systolic/diastolic ratio reflect flow or acidosis?

Cited by 27 publications

References 11 publications

Randomized trial of bolus phenylephrine or ephedrine for maintenance of arterial pressure during spinal anaesthesia for Caesarean section

Randomized trial of bolus phenylephrine or ephedrine for maintenance of arterial pressure during spinal anaesthesia for Caesarean section

Central arterial hemodynamics in small‐for‐gestational‐age fetuses before and during maternal hyperoxygenation: a Doppler velocimetric study with particular attention to the aortic isthmus

Effects of Increased Resistance to Umbilical Blood Flow on Fetal Hemodynamic Changes Induced by Maternal Oxygen Administration: A Doppler Velocimetric Study on the Sheep

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