Umbilical Cord Blood Gas Values Research Articles

Efficacy of sufentanil addition to ropivacaine epidural anaesthesia for Caesarean section

This prospective double-blind trial evaluated the effect of sufentanil addition to epidural ropivacaine for elective Caesarean section. Sixty healthy parturients were randomly assigned to receive an initial dose of 90 mg of plain ropivacaine, or 90 mg of ropivacaine plus 10 or 20 microg of sufentanil (n = 20 each). Before surgery, if necessary, additional epidural ropivacaine was injected. Primary outcome parameter was time to achieve sensory block at T4. Time to reach the sensory block was remarkably reduced (P < 0.001 each) by addition of 10 or 20 microg of sufentanil (21 +/- 8 min, 15 +/- 5 min, 11 +/- 4 min in the plain ropivacaine, the 10- and 20-microg sufentanil groups, respectively) whereas the visual analogue scale (VAS) scores at delivery were significantly reduced (P = 0.028) only by 20 microg of sufentanil (32 +/- 35 mm in the plain ropivacaine vs. 9 +/- 19 mm in the 20-microg sufentanil groups). The total dose of ropivacaine was significantly lower (P = 0.005) in patients receiving 20 microg of sufentanil (100.5 +/- 15.0 mg) compared with those treated with plain ropivacaine (118.5 +/- 17.3 mg). The incidence of maternal side-effects (hypotension, bradycardia, nausea, vomiting, shivering, pruritus) and neonatal outcome [APGAR score, neurologic and adaptive capacity (NAC) score, umbilical cord blood-gas values] did not differ between the groups. Our results suggest that addition of 20 microg of sufentanil improved the epidural anaesthesia with ropivacaine 0.75% for Caesarean section.

Epidural ropivacaine 1% with and without sufentanil addition for Caesarean section

So far only ropivacaine concentrations of 0.5 and 0.75% have been used for Caesarean section. This prospective double-blind trial evaluated the anaesthetic quality of ropivacaine 1% with and without sufentanil addition. Three groups of patients (n=20 each) scheduled for an elective Caesarean section were studied. The patients received initially 120 mg ropivacaine, or 120 mg ropivacaine plus 10 microg or 20 microg sufentanil. Additional epidural ropivacaine was injected if necessary. Primary outcome parameter was time to achieve sensory block at T4. Moreover, pain intensity at delivery (visual analogue scale, VAS), incidence of maternal side-effects (hypotension, bradycardia, nausea, vomiting, shivering, pruritus), and neonatal outcome (Apgar score, neurologic and adaptive capacity score, umbilical cord blood-gas values) were recorded. The onset time for the sensory block was not significantly different among the groups. Also, VAS scores at delivery did not differ significantly between the plain ropivacaine 1% group (18 +/- 29 mm), the 10-microg sufentanil group (1 +/- 5 mm), and the 20-microg sufentanil group (6 +/- 18 mm). The total dose of ropivacaine was significantly higher in the plain ropivacaine 1% group (145 +/- 19 mg) compared to the patients receiving additional 10 microg sufentanil (130 +/- 15 mg, P = 0.02) or 20 microg sufentanil (129 +/- 16 mg, P = 0.01). The incidence of maternal side-effects and neonatal outcome were similar in all groups. Ropivacaine 1% alone provided sufficient analgesia. Sufentanil addition did not significantly improve the quality of epidural anaesthesia with ropivacaine 1.0% for Caesarean section.

Use of umbilical artery base excess: Algorithm for the timing of hypoxic injury

Intrapartum asphyxia is responsible for only a small proportion of cerebral palsy cases, although obstetricians are often held accountable. Umbilical cord pH and blood gas values provide valuable information regarding the status of the infant at birth; base excess determination quantifies the magnitude of metabolic acidosis, the putative risk factor for central neurologic injury. Human and animals studies have confirmed normal values of base excess before labor, and consistent rates of base excess change in relation to the degree of fetal hypoxemia or heart rate patterns. Thus, the combination of assumed base excess values before labor and measured values after birth, together with an assessment of degrees of fetal hypoxemia during labor, permits an interpolation of fetal base excess values throughout the course of labor. Because threshold levels of base excess (eg, −12 mmol/L) have been associated with an increased risk of neonatal neurologic injury, this approach provides a framework for the assessment of fetal heart rate tracings during labor and, potentially, the timing of hypoxic/ischemic injury. (Am J Obstet Gynecol 2002;187:1-9.)

Recent cocaine use is not associated with fetal acidemia or other manifestations of intrapartum fetal distress.

The objective of this paper is to evaluate the impact of recent cocaine use on umbilical cord blood gas values in cocaine-dependent pregnant women who received formal prenatal care. Ninety-two cocaine-dependent pregnant women receiving comprehensive prenatal care were divided into two groups, with patients in Group A (n = 35) testing positive for cocaine metabolites at the time of delivery and Group B (n = 57) testing negative. One hundred and three patients with no history of drug or alcohol dependence served as the control group (Group C). Umbilical cord blood gases were obtained at all deliveries. Additional variables included 1 and 5-min Apgar scores, meconium staining of the amniotic fluid, route of delivery, premature rupture of the membranes, and length of nursery stay. There were no statistically significant differences between groups in either umbilical artery pH, pO2, pCO2, bicarbonate, or base excess. Similarly, there was no difference in meconium staining of the amniotic fluid, depressed Apgar scores, cesarean delivery, or neonatal length of stay. Our data do not support an association between recent cocaine use and fetal hypoxemia or acidemia, depressed 5-min Apgar scores, meconium staining of the amniotic fluid, or cesarean delivery in cocaine-dependent pregnant women enrolled in prenatal care.

UMBILICAL CORD BLOOD GAS ANALYSIS

Umbilical cord blood gas and pH values should always be obtained in the high-risk delivery and whenever newborn depression occurs. This practice is important because umbilical cord blood gas analysis may assist with clinical management and excludes the diagnosis of birth asphyxia in approximately 80% of depressed newborns at term. The most useful umbilical cord blood parameter is arterial pH. Sampling umbilical venous blood alone is not recommended because arterial blood is more representative of the fetal metabolic condition and because arterial acidemia may occur with a normal venous pH. A complete blood gas analysis may provide important information regarding the type and cause of acidemia and sampling the artery and vein may provide a more clear assessment. The sampling technique is simple and easily mastered by any treatment person in the delivery room. Preheparinized syringes ensure a consistent dose and amount of heparin. Depending on how normality is defined and on the population studied, normal ranges for umbilical cord blood gas values vary (see Table 1). In general, the lower range for normal arterial pH extends to at least 7.10 and that for venous pH to at least 7.20. Many different factors during pregnancy, labor, and delivery can affect cord blood gases. Umbilical blood sampling for acid-base status at all deliveries cannot be universally recommended because many facilities do not have the capabilities to support such a practice and in doing so may impose an excessive financial burden. Considering the costs, the accumulated published data, and the nonspecificity of electronic fetal monitoring in the evaluation of fetal oxygenation, it may be more rational to implement universal cord blood gas analysis. Care providers and institutions with the logistical capabilities in place should consider the cost efficacy of routine cord blood gas analysis because it is the gold standard assessment of uteroplacental function and fetal oxygenation/acid-base status at birth.

A comparison of umbilical cord blood gas values between newborns with and without true knots

To compare umbilical cord blood gas values in newborns with and without true knots, and to assess the potential impact of true knot formation on cord blood gases. Twelve newborn infants with true umbilical cord knots were identified and compared with a random control population of 104 newborn infants without true knots. The two groups were analyzed for 11 maternal-fetal variables to determine if they were comparable. Subsequently, the principal outcome variable of the study was evaluated: a comparison between the umbilical arterial and venous blood gas results of the true knot and control populations. The true knot and control populations were comparable with respect to the maternal-fetal variables analyzed. The umbilical cord blood gas values did not differ between groups, except for a slightly lower umbilical artery bicarbonate value in the control group (22.0 mEq/L) versus the true knot group (24.5 mEq/L), P = .025. There was no significant difference in the incidence of acidemia (umbilical artery pH less than 7.20) between the two groups. The presence of true umbilical cord knots does not alter the incidence of umbilical artery acidemia or change umbilical cord blood gas values. Review of the pertinent obstetric literature supports the hypothesis that true umbilical cord knots lack clinical significance.

The effect of maternal oxygen administration during the second stage of labor on umbilical cord blood gas values: A randomized controlled prospective trial

OBJECTIVE: Our aim was to determine whether supplemental oxygen during the second stage of normal labor affects cord blood gas and cooximetry values. STUDY DESIGN: Patients at term pregnancy were prospectively randomized to the control or treatment group at the onset of the second stage of labor. The treatment group received 10 L/min oxygen by face mask, which result in a mean fractional inspired oxygen concentration of 0.81. RESULTS: There were 86 patients randomized into the study. In the oxygen group there were significantly more cord arterial pH values < 7.20 ( 9 41 vs. 2 44 , p < 0.05). The control group was compared with two subgroups of patients receiving oxygen: those receiving oxygen therapy for ≤ 10 minutes and those receiving oxygen for >10 minutes. Analysis of variance demonstrated significant differences (7.285 ± 0.058, 7.312 ± 0.056, 7.237 ± 0.064; F test 8.3, p = 0.0005). Among several independent vriables, regression analysis demonstrated that only duration of oxygen therapy had a significant inverse relation to cord arterialpH ( F test = 15.6, p = 0.0002). CONCLUSIONS: Prolonged oxygen treatment during the second stage of normal labor resulted in a deterioration of cord blood gas values at birth.

Fetal heart rate decelerations and umbilical cord blood gas values

Although fetal heart rate (FHR) monitoring is widely used for fetal surveillance, there is still disagreement about the value of cardiotocography and the interpretation of FHR patterns. We addressed this in a prospective study in which umbilical cord blood gas and pH values at the time of cesarean section were related to different FHR patterns classified prior to surgery. The patient population consisted of 56 pregnant women with singleton fetuses of gestational age between 37 and 43 weeks. Indication for cesarean section was late FHR decelerations in 16 cases and variable decelerations in 17. Twenty-three patients operated on electively, and without any FHR abnormalities, served as a reference group. Late FHR decelerations were associated with the lowest pH and Po 2 levels in arterial as well as in venous blood. In the group with variable decelerations, the umbilical vein Po 2 was similar to that of the reference group, whereas the Po 2 value in the artery was significantly lower. Hence, in this clinical study a clear relationship was found between the different FHR patterns and changes in the acid-base balance.

Correlations between obstetric clinical events and umbilical cord blood acid-base and blood gas values.

Umbilical cord blood acid-base analysis may be used to assess the condition of fetus and newborn more objectively. Newborn acid-base status is an important criterion when we attempt to define perinatal asphyxia. It also has medicolegal ramifications because it enables the documentation of the presence of a biochemical milieu that is not related to the later development of cerebral palsy. We anticipate future research will focus on the redefinition of acidemia and its relationship to fetal and new-born outcomes.

Relationship between fetal biophysical activities and umbilical cord blood gas values

In a prospective study of 62 patients undergoing cesarean section before the onset of labor a fetal biophysical profile assessment was performed within 3 hours before the cesarean section. The presence or absence of the individual fetal biophysical activities (fetal heart rate reactivity, fetal breathing movements, fetal body movements, and fetal tone) were correlated with umbilical cord blood gas and acid-base measurements (artery and vein). Fetuses with nonreactive nonstress test results or the absence of breathing had significantly lower cord artery pH 1 P0 2 bicarbonate, and base excess measurements but not a significantly different PC0 2 level as compared with fetuses that had these activities present. Fetuses with the absence of movements or tone had lower pH 1 P0 2 bicarbonate, and base excess levels and higher PC0 2 levels as compared with fetuses with the presence of movements or tone, respectively. These blood gas and acid-base differences were observed in both umbilical cord artery and vein. Subsequent analysis of the blood gas and acid-base measurements of the fetuses with compromised biophysical activities revealed that there are different levels of acidemia, hypoxemia, and hypercapnia at which the individual biophysical activities are compromised. These data suggest that the first manifestations of fetal hypoxemia and acidemia are nonreactive nonstress test results and loss of fetal breathing; in advanced acidemia, hypoxemia, and hypercapnia fetal movements and fetal tone are compromised.

Effects of high-dose oxytocin augmentation on umbilical cord blood gas values in primigravid women

Active management of labor for term primigravid women with singleton, vertex presentations is associated with significant decreases in incidence of cesarean section and duration of labor, without adversely affecting major perinatal outcome variables. Concern has been expressed that high-dose oxytocin augmentation may increase the incidence of fetal compromise. With active management of labor, 43% of 1423 primigravid women received high-dose oxytocin augmentation during an 11-month period. Umbilical cord blood gas values from those who received high-dose oxytocin augmentation were compared with values in those who received no oxytocin. The mean arterial pH value in the no oxytocin group was 7.24 +/- 0.07, which is not significantly different (p greater than 0.10) from that of the oxytocin-augmented group, 7.23 +/- 0.07. Similarly, all other arterial and venous umbilical cord gas parameters were unaffected by high-dose oxytocin augmentation (p greater than 0.10). Our values were compared with other published values where labor was not managed according to the principles of active management of labor, and no differences were found. We report the largest series of cord blood pH values in primigravid women and conclude that there is no adverse effect of high-dose oxytocin augmentation or active management of labor on umbilical cord blood gas values at delivery.

CONTINUOUS INFUSION EPIDURAL ANALGESIA. DURING LABOR

The analgesic efficacy of the continuous epidural infusion of 0.0625% bupivacaine/0.0002% fentanyl was compared with the infusion of 0.125% bupivacaine alone in a randomized, double-blind study of nulliparous women. Each patient received, in sequence: 1) 3 ml of 0.5% bupivacaine with 1:200,000 epinephrine; 2) 6 ml of study solution 1 (bupivacaine-fentanyl group: 0.125% bupivacaine/0.0008% fentanyl; bupivacaine-only group: 0.25% bupivacaine alone); and 3) a continuous epidural infusion of study solution 2 at a rate of 12.5 ml/h (bupivacaine-fentanyl group: 0.0625% bupivacaine/0.0002% fentanyl; bupivacaine-only group: 0.125% bupivacaine alone). The epidural infusion was discontinued at full cervical dilatation, but patients who lacked perineal anesthesia received one or two 5-ml boluses of study solution 3 (bupivacaine-fentanyl group: 0.0625% bupivacaine alone; bupivacaine-only group: 0.125% bupivacaine alone). During the first stage of labor, 36 of 41 (88%) women in the bupivacaine-fentanyl group, and 37 of 39 (95%) women in the bupivacaine-only group, had analgesia of excellent or good quality (P = NS). During the second stage, 22 of 37 (59%) women in the bupivacaine-fentanyl group, and 23 of 35 (66%) women in the bupivacaine-only group, rated their analgesia as excellent or good (P = NS). Women in the bupivacaine-only group were more likely to have motor block at full cervical dilatation (P less than .001). There was no significant difference between groups in duration of the second stage of labor, duration of pushing, position of the vertex before delivery, method of delivery, Apgar scores, or umbilical cord blood gas and acid-base values.(ABSTRACT TRUNCATED AT 250 WORDS)