Umbilical Cord Blood Gas Analysis Research Articles

Umbilical cord blood lactate: A valuable tool in the assessment of fetal metabolic acidosis

Objective The aim of the present study was (1) to evaluate the relationship between umbilical cord arterial blood lactate and pH, standard base excess (SBE), and actual base excess (ABE) at delivery and (2) to suggest a cut-off level of umbilical cord arterial blood lactate in predicting fetal asphyxia using ROC-curves, where an ABE value less than −12 was used as “gold standard” for significant intrapartum asphyxia. Study design This is a descriptive study of umbilical cord arterial blood samples from 2554 singleton deliveries. The deliveries took place at the Department of Obstetrics and Gynaecology, Hvidovre University Hospital, Copenhagen, Denmark where umbilical cord blood sampling and blood gas analysis is part of the routine assessment of all newborns. Results We found significant correlations between lactate and pH ( r = −0.73), lactate and SBE ( r = −0.76), and lactate and ABE ( r = −0.83). ROC-curves suggested a lactate cut-off level of 8 mmol/l for indicating intrapartum asphyxia. Conclusion Lactate in arterial umbilical cord blood might be a more direct and accordingly more correct indicator of fetal asphyxia at delivery than pH and SBE (or ABE). Its potential as a predictor of neonatal outcome needs to be evaluated in future studies.

Use of umbilical cord blood gas analysis in the assessment of the newborn

Analysis of paired arterial and venous specimens can give insights into the aetiology of acidosis in the newborn

Reevaluation of Thiopental and Propofol using Bispectral Index in the Early Period of Cesarean Section

Background: Patients undergoing a cesarean section are at risk of experiencing intra-operative awareness. Thiopental and propofol are both commonly used to induce anesthesia in patients undergoing a cesarean section. This study compared the effect of propofol and thiopental on the anesthetic adequacy of parturients who received inhalation anesthetics using the bispectral index (BIS) in the early period of a cesarean section. Methods: Forty-five parturients were randomly assigned to receive either thiopental 4 mg/kg or propofol 2 mg/kg followed by 1% isoflurane with 50% N2O. The BIS, systolic and diastolic arterial pressure, heart rate, and the end-tidal concentration of isoflurane were recorded every minute for 10 minutes after intubation. The apgar score at 1 and 5 minutes and cord blood gas were assessed. Results: The systolic and diastolic pressure immediately after intubation were significantly lower in the Propofol group than in the Thiopental group. All the BIS values from 0 to 9 minutes after intubation were significantly lower in the Propofol group than in the Thiopental group. The Apgar scores and umbilical cord blood gas analysis were similar both groups. Conclusions: These results suggest that propofol is more suitable for the anesthetic adequacy and intraoperative awareness in the early period of a cesarean section than thiopental. (Korean J Anesthesiol 2007; 52: 49～54)

Spinal Anesthesia Using 0.5% Hyperbaric Bupivacaine/Meperidine Mixture for Cesarean Section

Background: Spinal anesthesia for cesarean section is regaining popularity because it can prevent pulmonary aspiration, failure of endotracheal intubation, depression of neonate by anesthetic agent in general anesthesia. Meperidine is unique in having significant local anesthetic properties that differentiate with morphine and fentanyl. Therefore, we compared the effects of adding meperidine 25 mg to intrathecal bupivacaine with fentanyl mixture. Methods: Sixty parturients were allocated (n = 30 per group) to group 1; 0.5% hyperbaric bupivacaine 7.5 mg plus meperidine 25 mg and group 2; 0.5% hyperbaric bupivacaine 10 mg plus fentanyl 25 in random order. Time to reach T4 sensory level, starting time of surgery, maximal spread of sensory block, incidence of complications, duration of motor block, perioperative analgesic effects, duration of postoperative analgesia were evaluated. We observed Apgar score and umbilical cord blood gas analysis for evaluation of the status of neonate. Results: There were no significant differences in Time to reach sensory level, starting time of surgery, maximal spread of sensory block, incidence of hypotension, perioperative analgesic effects, duration of motor block and neonatal status between two groups. The incidence of intraoperative nausea was greater in group 1 (60%) compared to the group 2 (20%) but the incidence of postoperative nausea and vomiting were not significantly different between two groups. Duration of postoperative analgesia was longer in group 1 (576.4 ﾝ 197.8 min) compared to the group 2 (192.6 0 75.5 min). Conclusions: Addition of meperidine 25 mg to intrathecal bupivacaine for Cesarean section improves intraoperative analgesia and also provides postoperative analgesia without significant adverse effects on the mother and neonate.

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.

Umbilical cord blood gas analysis in augmented labour

Labour augmentation with oxytocin may produce an excessive increase in frequency, duration or strength in uterine contractions which may result in fetal stress. Umbilical cord acid-base assessment provides an objective parameter in evaluating the neonatal condition immediately after delivery. We evaluated the neonatal condition in 235 deliveries where oxytocin was used for labour augmentation. The umbilical cord blood acid-base status was correlated with intrapartum cardiotocographic findings and Apgar scores. In two cases we noted umbilical artery pH <7.05 but the BDecF was not higher than 11 mmol/l and the 5-minute Apgar score was 8 in all cases. Our results indicate that the use of oxytocin for labour augmentation had no adverse effects on neonatal condition.

Umbilical cord blood gas analysis at the time of delivery

Aims: it is now recommended that cord blood acid-base measurement is performed routinely at time of delivery in the UK as a measure of fetal response to labour. However, there remains some uncertainty about the value of this procedure. In this paper our experience of cord blood analysis is described and the literature is reviewed to: (1) provide an overview of the physiological basis of cord blood acid-base assessment; (2) describe the appropriate methodology and identify issues which have contributed to confusion and undermined the value of cord blood sampling; and (3) address the practical issues of cord blood sampling. Conclusions: cord blood acid-base measurement has a sound physiological basis. It provides objective information which is a useful adjunct to subjective methods of newborn assessment, enables babies at risk of neonatal morbidity to be identified, can be helpful in litigation cases and is a prerequisite for clinical audit. However, to be of benefit the information must be correct and correctly interpreted.

Umbilical cord blood gas analysis at delivery

Fetal acid-base status is the end point that all antepartum and intrapartum surveillance tools are designed to assess, either directly or indirectly. Umbilical arterial blood pH is normal in 80% of depressed newborns, thereby proving the absence of birth asphyxia both in the delivery room and in the courtroom. The technique, normal ranges, and risks, benefits and cost analysis of routine versus selected umbilical blood sampling are considered. The American College of Obstetricians and Gynecologists recommends performing umbilical blood sampling for acid-base analysis in selected deliveries. However, in our opinion routine umbilical blood sampling at all deliveries has merit. (Am J Obstet Gynecol 1996;175:517-22.)

Umbilical cord blood gas analysis at delivery: a time for quality data.

To address the practical problems of routine umbilical cord blood sampling, to determine the ranges for pH, PCO2 and base deficit and to examine the relationships of these parameters between cord vessels. An observational study of umbilical cord artery and vein blood gas results. A large district general hospital in the UK. One thousand nine hundred and forty-two cord results from 2013 consecutive pregnancies of 34 weeks or more gestation, monitored by fetal scalp electrode during labour. Only 1448 (74.6%) of the 1942 supposedly paired samples had validated pH and PCO2 data both from an artery and the vein; 54 (2.8%) had only one blood sample available, 90 (4.6%) had an error in the pH or PCO2 of one vessel and in 350 (18%) pairs the differences between vessels indicated that they were not sampled from artery and vein as intended. Only 60% of the cases with an arterial pH less than 7.05 had evidence of a metabolic acidosis (base deficit in the extracellular fluid 10 mmol/l or more). Of all the cases, 2.5% had a venous-arterial pH difference greater than 0.22 units. Both artery and vein cord samples must be taken and the results screened to ensure separate vessels have been sampled. Interpretation of the results requires the examination of PCO2 and base deficit of the extracellular fluid from each vessel as well as the pH. Confusion about the value of cord gas measurements may be due to the use of erroneous data and inadequate definitions of acidosis which do not differentiate between respiratory and metabolic components.

Randomised trial of cardiotocography alone or with ST waveform analysis for intrapartum monitoring

It is possible to record the fetal electrocardiographic waveform (ECG) from the scalp electrode used in labour for detection of fetal heart rate. Animal and observational studies of changes in the ST waveform of the ECG during hypoxia suggest that a combination of heart rate and ST waveform analysis might improve the predictive value of intrapartum monitoring. In a randomised trial, we have studied intervention rates and neonatal outcome for high-risk labours monitored either by conventional cardiotocography (CTG) or by ST waveform analysis plus CTG. 1200 women with pregnancy of at least 34 weeks' gestation were assigned to the groups when the decision to apply a fetal scalp electrode was made. Neonatal outcome was assessed by umbilical-cord blood gas analysis, Apgar scores, resuscitation needed, and postnatal course. All recordings were retrospectively viewed by an observer unaware of clinical details to check adherence to the trial protocol. The addition of ST waveform monitoring to CTG substantially reduced the proportion of deliveries for fetal distress (ST + CTG 27/615 vs CTG 58/606; p < 0·001). The groups did not differ in rate of operative delivery for other reasons, incidence of asphyxia at birth, or neonatal outcome. Metabolic acidosis and low 5 min Apgar scores were less common in the ST + CTG than the CTG group, but not significantly so. The only case of birth asphyxia in the ST + CTG group was identified by both heart rate and ST changes. The review of recordings showed that the reduction in intervention rate was among cases with CTG patterns classified as normal or intermediate, whereas there was no difference in intervention rates among cases with abnormal recordings. Our findings confirm that ST waveform analysis discriminates CTG changes in labour and that our protocol for interpretation is safe. Further randomised studies are warranted.

Propofol for induction and maintenance of anaesthesia at Caesarean section A comparison with thiopentone/enflurane

A propofol infusion regimen and a standard general anaesthetic were compared in 40 Chinese women undergoing elective Caesarean section. Twenty patients received propofol 2 mg/kg for induction of anaesthesia followed by propofol 6 mg/kg/hour, while 20 patients received thiopentone 4 mg/kg with enflurane 1% for maintenance of anaesthesia. All patients were given atracurium and their lungs ventilated with nitrous oxide 50% in oxygen until delivery of the neonate. The hypertensive response after intubation was of shorter duration in the propofol group compared with the thiopentone group. Induction to delivery times ranged from 5 to 14 minutes and neonates from both groups had similar and satisfactory Apgar scores. Neurologic and Adaptive Capacity Scores and umbilical cord blood gas analysis. However, a prolonged propofol infusion time before delivery may cause lower Neurologic and Adaptive Capacity Scores. There were no differences in maternal recovery times or psychomotor performance.

Study of pH and gas analysis of umbilical arterial blood and apgar score as indicators of newborn health

Apgar score is most widely used evaluating indicator of newborn health, but it is very Subjective. Umbilical cord blood gas analysis is more objective and effective than Apgar score in evaluation of newborn status. Cord blood gas was changed slightly by processing of time after fetal birth. This study was undertaken to observe objectiveness and effectiveness of umbilical arterial blood gas analysis and effects of time interval of cord clamping to newborn health with 122 pregnant women and their babies. We observed following results : 1. There were poor correlation between Apgar score and umbilical cord arterial blood analysis in evaluating of newborn health (P>0.05). 2. There was no clinical significance of Apgar score or umbilical arterial blood gas analysis as single indicator in evaluating of newborn health (P>0.05). 3. Gas analysis and pH of umbilical arterial blood was more helpful in evaluating of newborn health than Apgasr score. 4. There were no significant effects of time interval of umbilical cord clamping to newborn health. 5. If there were no indications of early umbilical cord clamping, cord blood sampling at immediately after birth without cord clamping was more effective to evaluate newborn status.

Propofol infusion anaesthesia for Caesarean section

Two propofol infusion regimens and a standard general anaesthetic were compared in thirty Chinese women undergoing elective Caesarean section. After induction of anaesthesia with propofol 2 mg.kg-1, ten patients received propofol 6 mg.kg-1.hr-1 and nitrous oxide 50 per cent in oxygen while ten were given propofol 9 mg.kg-1.hr-1 with 100 per cent oxygen. The other ten patients received thiopentone 4 mg.kg-1 and nitrous oxide 50 per cent in oxygen with enflurane one per cent. Maternal recovery times and psychomotor performance were recorded. Neonates were assessed by Apgar scores, neurologic and adapative capacity scores (NACS) and umbilical cord blood gas analysis. Haemodynamic changes were similar immediately following induction but the low propofol infusion group had the best haemodynamic stability subsequently. Recovery times were fastest in the low-infusion group but there were no differences in later postbox testing. Neonatal Apgar scores and umbilical blood gas analysis were similar but NACS at two hours were poorer in the high infusion group. A propofol infusion coupled with nitrous oxide appears to be a satisfactory technique for Caesarean section.

Intraventricular haemorrhage—timing of occurrence and relationship to perinatal events

A total of 150 infants born at or before 34 weeks gestation had serial cranial ultrasound scans at age 8, 16, 24, 36, 48 h and 1 week. The overall incidence of IVH was 26%, but for infants less than 1500 g it was 51% and 50% of all haemorrhages were first detected in the first 8 h of life. Low-outlet forceps delivery and caesarean section offered some protection, but umbilical cord blood gas analysis did not support the hypothesis that hypoxia was causal. Respiratory distress and its complications were significantly associated with IVH. The more severe haemorrhages occurred in the less mature infants. The overall mortality in the study was 27% for the IVH group and 1.8% for the non-IVH group.