Higher Umbilical Artery pH Research Articles

The role of abnormal cerebroplacental ratio in predicting adverse fetal outcome in pregnancies with scheduled induction of labor.

To investigate the role of abnormal cerebroplacental ratio (CPR) in predicting adverse fetal outcome in pregnancies with induction of labor. This prospective observational study conducted at Medeniyet University Göztepe Training and Research Hospital between December 1, 2018 and October 31, 2019 enrolled women with scheduled induction of labor at or beyond 37weeks of pregnancy. Women with singleton non-anomalous fetuses with cephalic presentation and who had Bishop scores of 5 or less in pelvic examination were included in the study. Exclusion criteria were the presence of uterine scar history, non-cephalic presentation, multiple pregnancy, vacuum- or forceps-assisted delivery, and shoulder dystocia. Using fetal Doppler ultrasound, CPR was calculated (the ratio of umbilical artery to middle cerebral artery pulsatility index) and categorized into abnormal CPR (<1) and normal CPR (≥1). Data on maternal and delivery characteristics, fetal birth weight, and fetal complications were compared between the groups. A total of 145 women were included, 28 in the abnormal CPR group and 117 in the normal CPR group. Multivariate analysis revealed labor induction at a later week of pregnancy (odds ratio [OR] 10.33, P=0.001), lack of intrauterine growth restriction (IUGR) (OR 13.21, P=0.001), fetal distress (OR 8.14, P=0.003) or meconium aspiration (OR 159.91, P=0.001), and umbilical artery pH values greater than 7.31 (OR 17.51, P=0.015) to be associated with an increased likelihood of having normal (≥1) CPR values. Receiver operating characteristic analysis revealed association of normal CPR values with later labor induction (cut-off value of >38.3weeks, P=0.001), higher birth weight (cut-off value of >2460g, P=0.022) and higher umbilical artery pH (cut-off value of >7.31, P=0.007). Our findings revealed the significant role of abnormal CPR in predicting adverse fetal outcome in singleton pregnancies with scheduled induction of labor.

Effect of Chorionicity on Umbilical Cord Blood Acid-Base Analysis of the Second Twin.

Our objective was to determine whether chorionicity affects umbilical cord blood acid-base parameters of the second twin. This was a retrospective cohort of twin pregnancies delivered at ≥23 weeks of gestation at a tertiary hospital from 2010 to 2016. Patients were included if arterial and venous umbilical cord gas results were available for both newborns and chorionicity was confirmed histologically. Exclusion criteria included intrauterine fetal demise of either twin prior to labor, major fetal anomalies, monoamnionicity, uncertain chronicity and twin-to-twin transfusion syndrome. The primary outcome evaluated was the umbilical artery (UA) pH of the second twin. A total of 593 dichorionic (DC) and 86 monochorionic (MC) twin pregnancies were included. No difference in UA pH was observed between MC and DC twins. Among vaginal deliveries (n = 97), the UA pH of the first twin was higher than the second twin (7.26 vs. 7.24; p = .01). Twin-to-twin delivery interval (TTDI) ≥20 min was associated with a higher UA pH in the first twin compared to the second twin (7.25 vs. 7.16, respectively; p = .006). Multivariable logistic regression was used to predict arterial pH < 7.20 for the second twin; the most predictive factors were arterial pH < 7.20 for the first twin, chronic hypertension and prolonged TTDI. Chorionicity was not associated with any acid-base parameter of umbilical cord blood in either the first or second twin. No differences in neonatal outcomes were observed based on chorionicity or birth order. Populations with a lower cesarean delivery rate may yield different findings.

Metaraminol use during spinal anaesthesia for caesarean section: a meta-analysis of randomised controlled trials

IntroductionDuring caesarean section, the use of a vasopressor is often required to achieve haemodynamic stability of the parturient. Metaraminol is a vasopressor used in this context in some countries. However, the differences between metaraminol and other vasopressors remain unclear. MethodsA search of the PubMed, Cochrane Library, and Embase databases was performed to identify randomised controlled trials comparing the use of metaraminol with other vasopressors during spinal anaesthesia at caesarean section. The selected studies were subjected to meta-analysis and risk-of-bias assessment. ResultsFour randomised, controlled trials met the selection criteria and 409 parturients who underwent an elective caesarean section were included in this meta-analysis. The quality of these trials was good. Metaraminol was associated with higher umbilical arterial pH (standardised mean difference [SMD] 0.82, 95% CI 0.01 to 1.62, P=0.05); a lower incidence of fetal acidosis (RR 0.08, 95% CI 0.01 to 0.63, P=0.02); and a lower incidence of nausea or vomiting (RR 0.16, 95% CI 0.04 to 0.57, P=0.0005) than was ephedrine. Metaraminol resulted in higher umbilical arterial pH (SMD 0.42, 95% CI 0.15 to 0.68, P=0.002) but a higher incidence of reactive hypertension (RR 1.80, 95% CI 1.32 to 2.46, P=0.0002) than did phenylephrine. ConclusionThe results of this study showed that for spinal anaesthesia at elective caesarean section, metaraminol may be a more suitable vasopressor than ephedrine and its effects are at least not inferior to those of phenylephrine.

The Effect of Prophylactic Phenylephrine and Ephedrine Infusions on Umbilical Artery Blood pH in Women With Preeclampsia Undergoing Cesarean Delivery With Spinal Anesthesia: A Randomized, Double-Blind Trial.

Spinal anesthesia for cesarean delivery is associated with a high incidence of hypotension. Phenylephrine results in higher umbilical artery pH than ephedrine when used to prevent or treat hypotension in healthy women. We hypothesized that phenylephrine compared to ephedrine would result in higher umbilical artery pH in women with preeclampsia undergoing cesarean delivery with spinal anesthesia. This study was a randomized double-blind clinical trial. Nonlaboring women with preeclampsia scheduled for cesarean delivery with spinal anesthesia at Prentice Women's Hospital of Northwestern Medicine were randomized to receive prophylactic infusions of phenylephrine or ephedrine titrated to maintain systolic blood pressure >80% of baseline. Spinal anesthesia consisted of hyperbaric 0.75% bupivacaine 12 mg, fentanyl 15 µg, and morphine 150 µg. The primary outcome was umbilical arterial blood pH and the secondary outcome was umbilical artery base excess. One hundred ten women were enrolled in the study and 54 per group were included in the analysis. There were 74 and 72 infants delivered in the ephedrine and phenylephrine groups, respectively. The phenylephrine:ephedrine ratio for umbilical artery pH was 1.002 (95% confidence interval [CI], 0.997-1.007). Mean [standard deviation] umbilical artery pH was not different between the ephedrine 7.20 [0.10] and phenylephrine 7.22 [0.07] groups (mean difference -0.02, 95% CI of the difference -0.06 to 0.07; P = .38). Median (first, third quartiles) umbilical artery base excess was -3.4 mEq/L (-5.7 to -2.0 mEq/L) in the ephedrine group and -2.8 mEq/L (-4.6 to -2.2mEq/L) in the phenylephrine group (difference -0.6 mEq/L, 95% CI of the difference -1.6 to 0.3 mEq/L; P = .10). When adjusted for gestational age and infant gender, umbilical artery pH did not differ between groups. There were also no differences in the umbilical artery pH stratified by magnesium therapy or by the severity of preeclampsia. We were unable to demonstrate a beneficial effect of phenylephrine on umbilical artery pH compared with ephedrine. Our findings suggest that phenylephrine may not have a clinically important advantage compared with ephedrine with regard to improved neonatal acid-base status when used to prevent spinal anesthesia-induced hypotension in women with preeclampsia undergoing cesarean delivery.

A randomized trial comparing prophylactic phenylephrine and ephedrine infusion during spinal anesthesia for emergency cesarean delivery in cases of acute fetal compromise

BackgroundPrevious evidence showed that use of phenylephrine was associated with higher umbilical artery pH (UA pH) than ephedrine after elective cesarean delivery (CD). However, the best choice of vasopressor and its effect on funic gases in cases of acute fetal compromise require additional studies. MethodsNinety parturients showing acute fetal compromise during intrapartum period and taken up for CD (category II) under spinal anesthesia were randomized to receive prophylactic infusion of ephedrine 2.5mg/min or phenylephrine 30μg/min. Systolic blood pressure was targeted between 90% and 110% of baseline. Incidence of fetal acidosis (UA pH <7.2 and/or base deficit >12mmol/L) was recorded. Other parameters of cord gases, Apgar score, need for immediate resuscitation, maternal hemodynamics, and adverse events were also compared. ResultsNumber of neonates showing acidosis with ephedrine or phenylephrine was comparable (P=.22). Of these, newborns with base deficit >12mmol had low 1-minute Apgar scores (n=15/23). The ephedrine group had higher oxygen content in UA (P=.03). There was no adverse neonatal outcome during the period of observation. Incidence of maternal nausea and vomiting was higher with ephedrine than with phenylephrine (22.2% vs 4.4%; P=.02). Maternal bradycardia was observed with phenylephrine (P=.02). ConclusionOur data report similar fetal acidosis with either phenylephrine or ephedrine administered during spinal anesthesia for treating maternal hypotension in cases of emergency CD.

The Effects of Crystalloid and Colloid Preload on Cardiac Output in the Parturient Undergoing Planned Cesarean Delivery Under Spinal Anesthesia: A Randomized Trial

Hypotension after spinal anesthesia for cesarean delivery remains a major clinical problem. Fluid preloading regimens together with vasopressors have been used to reduce its incidence. Previous studies have used noninvasive arterial blood pressure measurement and vasopressor requirements to evaluate the effect of preload. We used a suprasternal Doppler flow technique to measure maternal cardiac output (CO) and corrected flow time (FTc, a measure of intravascular volume) before and after spinal anesthesia after 3 fluid preload regimens. We hypothesized that colloid solutions, compared with crystalloid, would produce the largest increase in CO and have the lowest incidence of hypotension. Sixty healthy term women scheduled for planned cesarean delivery under spinal anesthesia were recruited for this randomized, double-blind study. Baseline heart rate, systolic blood pressure (SBP), CO, and FTc were recorded in the left lateral tilt position. Patients were randomized to receive 1 of 3 fluid preload regimens given over 15 min: 1.5 L crystalloid (Hartman's solution), 0.5 L of 6% w/v hydroxyethyl starch (HES) solution (HES 0.5), or 1 L of 6% w/v HES solution (HES 1.0). Further measurements were made after fluid loading every 5 min for 30 min. After 30 min, spinal anesthesia was induced with hyperbaric bupivacaine 12.5 mg with fentanyl 15 microg and recordings were continued every 5 min for 20 min or until surgery started. The primary outcome, CO, was compared among groups. The incidence of hypotension (defined as a 20% reduction in SBP from the baseline), ephedrine use, and umbilical cord blood gases were also compared. Patient characteristics, heart rate, SBP, and cord gases were similar among groups. Although CO and FTc increased after preload in all groups (P < 0.005), this was only maintained with HES 1.0 after spinal anesthesia (P < 0.005). There were no differences among groups in the incidence of hypotension (70% vs 35% vs 65% for Hartman's solution, HES 0.5, and HES 1.0, respectively; P = 0.069) or mean ephedrine dose (10.4 vs 5.7 vs 9.7 mg; P = 0.26). Despite CO and FTc increases after fluid preload, particularly with HES 1.0 L, hypotension still occurred. The data suggest that CO increases after these preload regimens cannot compensate for reductions in arterial blood pressure after spinal anesthesia.

Patient-requested Neuraxial Analgesia for Labor

A systematic review, including a meta-analysis, on the timing effects of neuraxial analgesia (NA) on cesarean and instrumental vaginal deliveries in nulliparous women was conducted. Of 20 articles identified, 9 met the inclusion quality criteria (3,320 participants). Cesarean delivery (odds ratio, 1.00; 95% confidence interval, 0.82-1.23) and instrumental vaginal delivery (odds ratio, 1.00; 95% confidence interval, 0.83-1.21) rates were similar in the early NA and control groups. Neonates of women with early NA had a higher umbilical artery pH and received less naloxone. In the early NA group, fewer women were not compliant with assigned treatment and crossed over to the control group. Women receiving early NA for pain relief are not at increased risk of operative delivery, whereas those receiving early parenteral opioid and late epidural analgesia present a higher risk of instrumental vaginal delivery for nonreassuring fetal status, worse indices of neonatal wellness, and a lower quality of maternal analgesia.

The impact of chorionicity on umbilical cord acid–base values in twin gestations

Objective: To evaluate the impact of chorionicity on inter-twin differences in acid–base status at birth.Methods: Records for twin pregnancies delivered at ⩾ 24 weeks' gestation from 1 January 1990 to 31 June 2000 were reviewed. Collected data included maternal demographics, gestational age, fetal presentation, anesthesia, delivery mode, inter-twin interval, umbilical artery (UA) and venous (UV) acid–base values, Apgar scores and birth weights. The influence of chorionicity on umbilical cord biochemistry was evaluated. (p < 0.05 was considered significant.)Results: Analysis was carried out in 87 twin pairs (29 monochorionic, MC; and 58 dichorionic, DC). MC and DC twins were similar in maternal age (25.5 vs. 28.2 years), estimated gestational age (33.7 vs. 33.6 weeks), Cesarean delivery (55.2 vs. 52.6%), delivery interval (10 v s.5 min) and respective birth weights (twin A,1882 vs. 1981; and twin B,1828 vs. 1872 g). MC first twins had a higher UA pH (7.31 ± 0.05 vs. 7.26 ± 0.08; p = 0.0005) than DC first twins. MC first and second twins had higher UA and UV bicarbonate levels than their DC counterparts (ΔpH = 21.7 ± 5.1 vs. 18.5 ± 3.1 mmol/l and 22.0 ± 3.5 vs. 19.6 ± 2.5 mmol/l, respectively; p = 0.003). MC twins were more discordant in UA pH than DC twins (ΔpH = 0.043 ± 0.09 vs. 0.003 ± 0.07; p = 0.009). MC and DC twins had a similar venous pH (ΔpH = 0.01 ± 0.06 vs. 0.02 ± 0.06; p = 0.5).Conclusions: There is a significant association between placental chorionicity and umbilical cord biochemistry in twins. Although it is possible that the mechanism of this finding is related to placental angioarchitecture, it is unlikely to be a result of simple mixing of blood volumes between twins. The physiology of underlying processes requires further study.