Severe umbilical cord acidemia and neurological outcome in preterm and full-term neonates

Umbilical cord blood acid-base analysis at birth and long-term neurodevelopmental outcomes in children: a systematic review and meta-analysis

BACKGROUND

Umbilical cord blood acid-base sampling is routinely performed at many hospitals. Recent studies have questioned this practice and the association of acidosis with cerebral palsy.

OBJECTIVE

To investigate the associations between the results of umbilical cord blood acid-base analysis at birth and long-term neurodevelopmental outcomes and mortality in children.

SEARCH STRATEGY

We searched six databases using the search strategy: umbilical cord AND outcomes.

SELECTION CRITERIA

Randomised controlled trials, cohorts and case-control studies from high-income countries that investigated the association between umbilical cord blood analysis and neurodevelopmental outcomes and mortality from 1 year after birth in children born at term.

DATA COLLECTION AND ANALYSIS

We critically assessed the included studies, extracted data and conducted meta-analyses comparing adverse outcomes between children with and without acidosis, and the mean proportions of adverse outcomes. The certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach.

MAIN RESULTS

We have very low confidence in the following findings: acidosis was associated with higher cognitive development scores compared with non-acidosis (mean difference 5.18, 95% CI 0.84-9.52; n = two studies). Children with acidosis also showed a tendency towards higher risk of death (relative risk [RR] 5.72, 95% CI 0.90-36.27; n = four studies) and CP (RR 3.40, 95% CI 0.86-13.39; n = four studies), although this was not statistically significant. The proportion of children with CP was 2.39/1000 across the studies, assessed as high certainty evidence.

CONCLUSION

Due to low certainty of evidence, the associations between umbilical cord blood gas analysis at delivery and long-term neurodevelopmental outcomes in children remains unclear.

Risk factors for and consequences of difficult fetal extraction in emergency caesarean section. A retrospective registry-based cohort study

INTRODUCTION

This study aimed to assess risk factors for difficult fetal extraction in emergency caesarean sections, focusing on top-up epidural anesthesia compared to spinal anesthesia. Additionally, this study addressed consequences of difficult fetal extraction on neonatal and maternal morbidity.

MATERIAL AND METHODS

This retrospective registry-based cohort study included 2,332 of 2,892 emergency caesarean sections performed with local anesthesia during 2010-2017. Main outcomes were analyzed by crude and multiple adjusted logistic regression providing odds ratios.

RESULTS

Difficult fetal extraction was found in 14.9% of emergency caesarean sections. Risk-factors for difficult fetal extraction included top-up epidural anesthesia (aOR:1.37[95 %CI 1.04-1.81]), high pre-pregnancy BMI (aOR:1.41[95 %CI 1.05-1.89]), deep fetal descent (ischial spine: aOR:2.53[95 %CI 1.89-3.39], pelvic floor: aOR:3.11[95 %CI 1.32-7.33]), and anterior placental position (aOR:1.37[95 %CI 1.06-1.77]). Difficult fetal extraction was associated with increased risk of low umbilical artery pH 7.00-7.09 (aOR:3.50[95 %CI 1.98-6.15]) pH ≤ 6.99 (aOR:4.20[95 %CI 1.61-10.91]), five-minute Apgar score ≤ 6 (aOR:3.41[95 %CI 1.49-7.83]) and maternal blood loss (501-1,000 ml: aOR:1.65[95 %CI 1.27-2.16], 1,001-1,500 ml: aOR:3.24[95 %CI 2.24-4.67], 1,501-2,000 ml: aOR:3.94[95 %CI 2.24-6.94] and ≥ 2001 ml: aOR:2.76[95 %CI 1.12-6.82]).

CONCLUSION

This study identified four risk factors for difficult fetal extraction in emergency caesarean section: top-up epidural anesthesia, high maternal BMI, deep fetal descent and anterior placental position. Additionally, difficult fetal extraction was associated with poor neonatal and maternal outcomes.

Acid-base and metabolic parameters and cerebral oxygenation during the immediate transition after birth-A two-center observational study

OBJECTIVE

The association between blood glucose level and cerebral oxygenation (cerebral regional oxygen saturation [crSO2] and cerebral fractional tissue oxygen extraction [FTOE]) in neonates has already been described. Aim of the present study was to investigate if acid-base and other metabolic parameters have an impact on cerebral oxygenation immediately after birth in preterm and term neonates.

STUDY DESIGN

Post-hoc analyses of secondary outcome parameters of two prospective observational studies were performed. Preterm and term neonates born by caesarean section were included, in whom i) cerebral near-infrared spectroscopy (NIRS) measurements were performed during the first 15 minutes after birth and ii) a capillary blood gas analysis was performed between 10 and 20 minutes after birth. Vital signs were routinely monitored with pulse oximetry (arterial oxygen saturation [SpO2] and heart rate [HR]). Correlation analyses were performed to investigate potential associations between acid-base and metabolic parameters (lactate [LAC], pH-value [pH], base-excess [BE] and bicarbonate [HCO3]) from capillary blood and NIRS-derived crSO2 and FTOE at 15 minutes after birth.

RESULTS

One-hundred-fifty-seven neonates, 42 preterm neonates (median gestational age [IQR] 34.0 weeks [3.3], median birth weight 1845g [592]) and 115 term neonates (median gestational age [IQR] 38.9 weeks [1.0], median birth weight 3230g [570]) were included in the study. Median crSO2 [IQR] values at 15 minutes after birth were 82% [16] in preterm neonates and 83% [12] in term neonates. Median FTOE [IQR] values at 15 minutes after birth were 0.13 [0.15] in preterm neonates and 0.14 [0.14] in term neonates. In preterm neonates, higher LAC and lower pH and BE were associated with lower crSO2 and higher FTOE. In term neonates, higher HCO3 was associated with higher FTOE.

CONCLUSION

There were significant associations between several acid-base and metabolic parameters and cerebral oxygenation in preterm neonates, while in term neonates only HCO3 correlated positively with FTOE.

Predicting long-term neurodevelopmental outcomes in very preterm neonates by umbilical cord gas parameters

BACKGROUND

The predictive value of acidemia at birth on long-term neurodevelopmental outcomes remains poorly understood, especially in preterm neonates.

OBJECTIVE

This study aimed to assess the relationship between the umbilical artery acid-base status and major neurodevelopmental disability at an age of between 5 and 8 years among children born very prematurely.

STUDY DESIGN

We performed a secondary analysis of the data from a follow-up study of a prospective cohort of 457 children aged between 23 weeks and 31 weeks and 6 days from 1996 to 2001. Arterial cord gas parameters that were <10th percentile in the original cohort of 457 neonates (ie, pH of <7.1, base deficit of <-8.6 mEq/L, and a partial pressure of CO2 of >77 mm Hg) were considered abnormal. Sensitivity analyses considered alternative definitions for abnormal cord gases including a pH of <7.0 or base deficit of <-12 mEq/L. The primary outcome was a composite of major neurodevelopmental disability, including an intelligence quotient score of <70, cerebral palsy, blindness, deafness, abnormal balance, impaired cognition, dystonia, and seizure disorder. A logistic regression analysis was used to adjust for race and caregiver intelligence quotient score and, in an additional analysis, for gestational age.

RESULTS

A total of 259 of 261 maternal-infant dyads were evaluated at a mean child age of 6.8 years, with complete umbilical cord gas data for 228 of those. Infants with an abnormal pH and a base deficit (defined above) were over 4-fold more likely to have the composite disability and an intelligence quotient score of <70. These increased odds persisted after adjusting for age and caregiver intelligence quotient score, but when considering gestational age as well, none of the umbilical cord gas parameters significantly predicted the presence of the composite disability or an intelligence quotient score of <70. However, when using the stricter umbilical cord gas criteria (ie, pH of <7.0 and a base deficit of <-12 mEq/L), a base deficit of <-12 mEq/L was independently associated with both neurodevelopmental disability and an intelligence quotient score of <70.

CONCLUSION

When defined more strictly, abnormal umbilical cord gases, specifically a base deficit of <-12 mEq/L, are associated with an increased risk for major long-term neurodevelopmental disability and an intelligence quotient score of <70 in children born very prematurely.

Is there a role for therapeutic hypothermia administration in term infants with mild neonatal encephalopathy?

OBJECTIVE

Identifying term infants presenting with early mild neonatal encephalopathy (NE) as candidates for therapeutic hypothermia (TH) remains unclear. Study objectives were to characterize the neonatal clinical, magnetic resonance imaging (MRI), and longer-term outcome in infants with mild NE treated with TH.

STUDY DESIGN

Retrospective cohort study of infants admitted with mild or moderate NE treated with TH. Enrollment criteria included a sentinel event, severe acidosis, DR interventions, and low Apgar scores.

RESULTS

Infants with mild (n = 11) and moderate NE (n = 37) received TH. Mild NE findings included hyperalertness (64%), hypotonia (73%), high level sensory response (91%); 64% progressed to moderate NE. Infants with mild vs. moderate NE had less severe MRI changes (0 vs. 16%) and no cerebral palsy (CP) (0 vs. 13%).

CONCLUSIONS

Outcomes were favorable with mild NE whereas four infants with moderate NE developed CP. A potential role for TH in this population requires further study.

Investigation of the relationship between umbilical cord pH and intraventricular hemorrhage of infants delivered preterm

OBJECTIVE

We measured the level of pH gases in premature infants at birth, and examined the relationship between brain ultrasonography on the third and seventh day after birth. A case-control study conducted at the Neonatal Intensive Care Unit (NICU) of Shahid Akbar Abadi Hospital, Iran, during the years 2016-2017.

METHODS

All premature infants who were admitted to NICU were enrolled in the current study. At birth, a blood gas sample was taken from the umbilical cord of the infants. On the third and seventh day after birth, an ultrasound of the brain of each neonate was performed by a radiologist. The umbilical cord was evaluated for blood gases in 72 neonates (mostly boys).

RESULTS

Sixty-six newborns had normal sonography, and 16.7% (12 cases) had anomalies. A total of 75% of the 8 infants with intravenous bleeding were girls, which were significantly different from those in the non-hemodynamic group (62.5% male) (P 0.049). However, the type of delivery, mean weight, height, head circumference, the circumference of the chest, and Apgar score did not differ between the two groups. Mean pH, HCO3- and PCO2 in umbilical cord blood gas samples were not significantly different between the two groups with or without intraventricular hemorrhage (IVH). Although it was not related to gender and type of delivery in newborns.

CONCLUSION

Blood gases do not help in determining the occurrence of IVH in infants. Nevertheless, it is associated with immaturity and fetal age.

Newborn blood gas derangements of children born extremely preterm and neurocognitive dysfunctions at age 10 years

Among 740 children born extremely preterm, we evaluated the relationship between the highest and lowest quartiles of the distributions of PaO₂ and PaCO₂, as well as the lowest quartile of pH on one day, and separately on two days, and the risk of neurocognitive, language, and behavioral dysfunctions at age 10 years. Children who had hypoxemia, hyperoxemia, hypocapnia, hypercapnia, and acidemia, sometimes on only one day, and sometimes on two or more days, were more likely than others to have a high illness severity score (within the first 12 postnatal hours), and 10 years later to have multiple dysfunctions. The tendency of blood gas derangements to be associated with high illness severity scores and with multiple dysfunctions 10 years later is compatible with the possibility that blood gas derangements are indicators of physiologic instability/vulnerability/immaturity rather than contributors to brain damage.

A burden of knowledge: A qualitative study of experiences of neonatal intensive care nurses' concerns when keeping information from parents

Improved life-sustaining technology in the neonatal intensive care has resulted in an increased probability of survival for extremely premature babies. In the neonatal intensive care, the condition of a baby can deteriorate rapidly. Nurses and parents are together for long periods at the bedside and so form close and trusting relationships. Neonatal nurses as the constant caregivers may be presented with contradictory demands in attempting to meet the baby's needs and being a patient and family advocate. This article aims to explore the issues arising for neonatal nurses when holding information about changes to a condition of a baby that they are unable to share with parents. Data were collected via interviews with 24 neonatal nurses in New South Wales, Australia. A qualitative approach was used to analyse the data. The theme 'keeping secrets' was identified and comprised of three sub-themes 'coping with potentially catastrophic news', 'fear of inadvertent disclosure' and 'a burden that could damage trust'. Keeping secrets and withholding information creates internal conflict in the nurses as they balance the principle of confidentiality with the parent's right to know information. The neonatal nurses experienced guilt and shame when they were felt forced by circumstances to keep secrets or withhold information from the parents of extremely premature babies.

Umbilical blood gas analysis in preeclamptic versus healthy pregnancies with preterm birth

OBJECTIVE

Comparing the value of umbilical cord arterial blood gas (UC-ABG) analysis in the prediction of neonatal mortality and morbidity in the preeclamptic versus healthy pregnancies with preterm birth.

METHODS

Eight hundred sixteen preterm (born at <37 gestational weeks) neonates with no other morbidities who were born by cesarean section were evaluated. Immediately after delivery, UC-ABG analysis was performed and the neonates were followed.

RESULTS

Preeclamptic women had lower umbilical cord blood (UCB) pH (7.2 4 ± 0.1 versus 7.2 7 ± 0.08, p = 0.008) and higher UCB base deficit (BD) (3.5 ± 3.7 versus 2.2 ± 3.4, p = 0.005) compared with controls. In the preeclamptic group, UCB metabolic acidosis (pH < 7.15 and B.D > 8) was not independently associated with neonatal morbidity or mortality, while in the control group UCB metabolic acidosis was independently associated with low 10-min Apgar (OR, 4.9; 95%CI 1.37-18.03), respiratory distress syndrome (OR, 2.37; 95%CI 1.05-6.17), intraventricular hemorrhage (OR, 3.01; 95%CI 1.13-7.99), and neonatal mortality (OR, 17.33; 95%CI 4.51-66.53).

CONCLUSIONS

The preterm neonates born to preeclamptic mothers have lower UCB pH and higher BD. In these neonates, UCB acidosis is not independently associated with any adverse neonatal outcomes. In contrast, in the preterm neonates born to healthy mothers, UCB metabolic acidosis is independently associated with neonatal mortality and morbidity.

Short-Term Variation of the Fetal Heart Rate for Predicting Neonatal Acidosis in Preeclampsia

Introduction: The aim of this study was to measure the performance of short-term variation (STV) in predicting the onset of neonatal acidosis in fetuses at risk due to maternal preeclampsia. Material and Methods: This retrospective study examined data from a series of 159 women with singleton pregnancies, hospitalized for preeclampsia in a level 3 reference maternity hospital in northern France, with an STV measurement in the 24 h preceding cesarean delivery and a measurement of the newborn's arterial cord pH at birth. The main outcome was determined by a correlation between STV and neonatal pH. Results: The last computerized fetal heart rate analysis took place a mean of 7.9 ± 6.3 h before birth, and neonatal acidosis was diagnosed in 38 newborns (23.9%). Although STV and umbilical artery pH at birth were significantly correlated (ρ = 0.16, p < 0.05), the performance of STV in predicting neonatal acidosis was poor, with an area under the ROC curve of 0.63. The sensitivity reached only 50.0% and the specificity 71.9% at the best STV threshold for predicting acidosis. Conclusion: The performance of STV for screening for neonatal acidosis is poor in women with preeclampsia. The divergent results between studies are probably due to the variable intervals between STV measurement and birth.

Population study of neurodevelopmental outcomes of extremely premature infants admitted after office hours

AIM

The aim of the study was to compare neurodevelopmental outcomes of extremely preterm infants admitted during (OH) and after (AH) office hours.

METHODS

A retrospective review of the New South Wales and Australian Capital Territory Neonatal Intensive Care Units' (NICUs) Data Collection of all infants <29 weeks gestation admitted to New South Wales and Australian Capital Territory NICUs between January 1998 and December 2004 was conducted. The primary outcome was moderate/severe functional disability (FD) at 2-3 years follow-up defined as developmental delay (Griffiths Mental Developmental Scales general quotient or Bayley Scales of Infant Development-II mental developmental index >2 standard deviations below the mean), cerebral palsy (unable to walk without aids), deafness (requiring bilateral hearing aids) or blindness (visual acuity <6/60 in the better eye).

RESULTS

Mortality and age at follow-up were comparable between the AH and OH groups. Developmental outcome was evaluated in 972 (74.9%) infants admitted during AH and 501 (74.6%) admitted during OH. FD was not significantly different between the AH and OH groups (17.1% vs. 14.8%, adjusted odds ratio 1.131, 95% confidence interval 1.131 (0.839-1.523), P = 0.420). There were no significant differences between AH and OH infants with cerebral palsy (9.6% vs. 7.6%), developmental delay (5.4% vs. 5.0%) or any other component of FD.

CONCLUSION

There is little circadian variation in mortality and adverse neurodevelopmental outcomes in an NICU network with the current model of after hours staffing and support, and sharing of NICU workload within a network.

Outcomes of extremely low birthweight infants with acidosis at birth

OBJECTIVES

To test the hypothesis that acidosis at birth is associated with the combined primary outcome of death or neurodevelopmental impairment (NDI) in extremely low birthweight (ELBW) infants, and to develop a predictive model of death/NDI exploring perinatal acidosis as a predictor variable.

STUDY DESIGN

The study population consisted of ELBW infants born between 2002 and 2007 at National Institute of Child Health and Development (NICHD) Neonatal Research Network hospitals. Infants with cord blood gas data and documentation of either mortality prior to discharge or 18-22 month neurodevelopmental outcomes were included. Multiple logistic regression analysis was used to determine the contribution of perinatal acidosis, defined as a cord blood gas with a pH<7 or base excess (BE) <-12, to death/NDI in ELBW infants. In addition, a multivariable model predicting death/NDI was developed.

RESULTS

3979 patients were identified of whom 249 had a cord gas pH<7 or BE<-12 mEq/L. 2124 patients (53%) had the primary outcome of death/NDI. After adjustment for confounding variables, pH<7 and BE<-12 mEq/L were each significantly associated with death/NDI (OR=2.5 (1.6, 4.2) and OR=1.5 (1.1, 2.0), respectively). However, inclusion of pH or BE did not improve the ability of the multivariable model to predict death/NDI.

CONCLUSIONS

Perinatal acidosis is significantly associated with death/NDI in ELBW infants. Perinatal acidosis is infrequent in ELBW infants, however, and other factors are more important in predicting death/NDI.

Two-year outcomes for infants with low cord pH at birth

OBJECTIVE

To determine the long-term outcome of infants born with cord pH ≤ 7.0 and no clinical evidence of asphyxia at birth.

DESIGN

SETTING

Tertiary Referral Centre. A prospective matched cohort study was conducted. 51 term infants were recruited following singleton birth with venous cord pH ≤ 7.0. For each recruited baby a healthy baby with normal cord pH ≥ 7.20 was recruited matched for gestation, gender and mode of delivery. Ages and Stages Questionnaires (ASQ)(TM) and Health Screening Questionnaires (HSQ) were sent out at 24 months of age. Two independent assessors, blinded to the case assignment, reviewed intrapartum and neonatal events to look for clinical evidence of birth asphyxia among the cases.

RESULT

From 102 infants recruited, 62 questionnaires (24 cases, 38 controls) were returned. 20 matched pairs with no clinical evidence of birth asphyxia were available for analysis. The groups were similar except in terms of birth weight; the pH ≥ 7.0 group had mean birth weight 584 g lower than controls (p = 0.005). The ASQ motor scores were lower in children born with low cord pH (p = 0.019); however, once adjusted for birth weight, the difference was not significant (p = 0.289).

CONCLUSION

It is unlikely that abnormal cord pH in otherwise healthy neonates leads to a substantially increased risk of abnormal neurodevelopmental outcome or severe health problems by 2 years of age.

Effectiveness of electronic fetal monitoring with additional ST analysis in vertex singleton pregnancies at >36 weeks of gestation: an individual participant data metaanalysis

OBJECTIVE

The purpose of this study was to assess the effectiveness of electronic fetal monitoring (EFM) alone and with additional ST analysis (EFM + ST) in laboring women with a singleton term pregnancy that is in cephalic presentation in the prevention of metabolic acidosis by the application of individual patient data metaanalysis.

STUDY DESIGN

We conducted an individual patient data metaanalysis using data from 4 randomized trials, which enabled us to account for missing data and investigate relevant subgroups. The primary outcome was metabolic acidosis, which was defined as an umbilical cord-artery pH <7.05 and a base deficit that had been calculated in the extra cellular fluid compartment >12 mmol/L. We performed 8 explanatory subgroup analyses for 8 different endpoints.

RESULTS

We analyzed data from 12,987 women and their newborn infants. Metabolic acidosis was present in 57 women (0.9%) in the EFM + ST group and 73 women (1.1%) in the EFM alone group (relative risk [RR], 0.76; 95% CI, 0.53-1.10). Compared with EFM alone, the use of EFM + ST resulted in a reduction in the frequency of instrumental vaginal deliveries (RR, 0.90; 95% CI, 0.83-0.99) and fetal blood samples (RR, 0.49; 95% CI, 0.44-0.55). Cesarean delivery rates were comparable between both groups (RR, 0.99; 95% CI, 0.91-1.09). Subgroup analyses showed that EFM + ST resulted in fewer admissions to a neonatal intensive care unit for women with a duration of pregnancy of >41 weeks (RR, 0.61; 95% CI, 0.39-0.95).

CONCLUSION

EFM + ST does not reduce the risk of metabolic acidosis, but it does reduce the need for instrumental vaginal deliveries and fetal blood sampling.

Relationship between severe acidemia, verbal abilities, and behavior in a Spanish cohort of 5-year-old children born at term

AIM

To determine whether a relationship exists between the markers of severe acidemia (SA) and the developmental, verbal, and behavioral characteristics of children with SA born at term 5 years previously, without apparent neurological impairment.

METHODS

A cohort of 76 children-38 with SA (pH < 7, base deficit ≥12 mmol/L) and 38 non-SA (pH ≥ 7.20)-were evaluated using the Battelle Developmental Inventory, McCarthy's Verbal Scale, the Token Test for Children, and the Conners 3rd Edition-Parent. The relationships between markers of SA and verbal and behavioral scores were analyzed with parametric correlations. Multiple regression analysis was used to determine the possible effect of these markers on verbal abilities, verbal memory, and attention.

RESULTS

Although none of the scores were in the "impaired" range, the SA group scored lower in verbal index (p = .000) and verbal memory (p = .004) on the McCarthy's Scales and in verbal comprehension (p = .001) on the Token Test for Children-2, and higher on the inattention (p = .003) and hyperactivity-impulsivity domains of the Conners Scales (p = .009) compared with the control group. There were no differences between the groups in the motor, personal-social, or cognitive domains on the Battelle Developmental Inventory. The SA markers were found to be predictors, accounting for 61.6% of verbal variability.

CONCLUSIONS

SA markers reflect mild long-term consequences regarding verbal abilities and inattentiveness among children born at term without apparent neurological impairment on discharge but do not suggest severe impairment to the 5-year development of children. The authors recommend that these children should be monitored to determine whether they need or might benefit from an early intervention program.

Early chloride intake does not parallel that of sodium in extremely-low-birth-weight infants and may impair neonatal outcomes

BACKGROUND AND OBJECTIVE

Accurate data on the optimal chloride (Cl) intake in premature infants are scarce. The aim of the present study was to describe Cl intakes in the first 10 days of life and to assess the relations between high Cl intakes and corrected serum Cl level or markers of severe acidosis in infants <28 weeks' gestation.

METHODS

Retrospective cohort study including all of the infants <28 weeks admitted to the neonatal intensive care unit during a 3-year period and cared for from birth until day 10 or more.

RESULTS

Fifty-six infants were included. Cumulative total Cl intakes reached 9.6 ± 3.7 mmol/kg at day 3 and 49.2 ± 13.5 mmol/kg at day 10. Inadvertent intakes (from intravenous fluids other than parenteral nutrition) represented on average 70% of total Cl intakes in the first 3 days. Difference between Cl and sodium intakes reached 7.8 ± 4.8 mmol/kg at day 10 and mainly originated from parenteral nutrition. By multivariate analysis, cumulative Cl intake >10 mmol/kg during the first 3 days was an independent risk factor of base excess <-10 mmol/L. Cumulative Cl intake >45 mmol/kg during the first 10 days was an independent risk factor of corrected chloremia >115 mmol/L and of base excess <-10 mmol/L.

CONCLUSIONS

Cumulative Cl intake >10 mmol/kg during the first 3 days (ie, 3.3 mmol · kg (-1) · day(-1) on average) and >45 mmol/kg during the first 10 days (ie, 4.5 mmol · kg (-1) · day(-1) on average) may have unwanted metabolic consequences and should be avoided. Imbalance between electrolytes provided by the parenteral nutrition solution need to be detected and corrected.

Blood protein concentrations in the first two postnatal weeks associated with early postnatal blood gas derangements among infants born before the 28th week of gestation. The ELGAN Study

AIM

To explore the relationships between blood gas derangements and blood concentrations of inflammation-related proteins shortly after preterm birth.

DESIGN

Observational cohort.

SETTING

Fourteen neonatal intensive care units.

SUBJECTS

Seven hundred and forty five infants born before the 28th week of gestation who were classified by their blood gas derangements during the first three postnatal days and by the concentrations of 25 proteins in their blood on days 1, 7, and 14. We classified these newborns by whether or not they had a highest or lowest PaO2, PCO2, and lowest pH in the most extreme quartile, and by whether or not they had a protein concentration in the highest quartile.

RESULTS

Blood gas derangements on two days were much more likely to be accompanied or followed by sustained or recurrent systemic inflammation than a derangement on only one day. This was most evident for acidemia, and slightly less so for hypercapnia.

CONCLUSIONS

Our finding that protein concentration patterns indicative of systemic inflammation are associated with several blood gas derangements raises the possibility that organ damage attributed to these derangements might be accompanied by or involve an inflammatory response.

Early blood gas abnormalities and the preterm brain

The authors explored associations between blood gas abnormalities in more than 1,000 preterm infants during the first postnatal days and indicators of neonatal brain damage. During 2002-2004, women delivering infants before 28 weeks' gestation at one of 14 participating institutions in 5 US states were asked to enroll in the study. The authors compared infants with blood gas values in the highest or lowest quintile for gestational age and postnatal day (extreme value) on at least 1 of the first 3 postnatal days with the remainder of the subjects, with separate analyses for blood gas abnormalities on multiple days and for partial pressure of oxygen in the alveolar gas of <35. Outcomes analyzed were ventriculomegaly and an echolucent lesion on an ultrasound scan in the neonatal intensive care unit, and cerebral palsy, microcephaly, and a low score on a Bayley Scale of Infant Development at 24 months. Every blood gas derangement (hypoxemia, hyperoxemia, hypocapnia, hypercapnia, and acidosis) was associated with multiple indicators of brain damage. However, for some, the associations were seen with only 1 day of exposure; others were evident with 2 or more days' exposure. Findings suggest that individual blood gas derangements do not increase brain damage risk. Rather, the multiple derangements associated with indicators of brain damage might be indicators of immaturity/vulnerability and illness severity.

Cord blood erythropoietin and interleukin-6 for prediction of intraventricular hemorrhage in the preterm neonate

OBJECTIVE

To evaluate cord blood erythropoietin (EPO) and interleukin-6 (IL-6) levels to predict preterm infants at risk of developing intraventricular hemorrhage (IVH).

METHODS

Levels of umbilical cord EPO, acid-base status and IL-6 were analyzed in 116 consecutive, preterm newborns (GA at delivery: 29 [23-34 ] weeks) born to mothers who had a clinically indicated amniocentesis to rule out infection. Early-onset neonatal sepsis (EONS) was diagnosed using symptoms, hematological criteria and blood cultures.

RESULTS

IVH was diagnosed by cranial ultrasounds. The prevalence of IVH in our population was 25% (29/116). There was a direct relationship between cord blood EPO and cord blood IL-6 concentration (r = 0.225, p = 0.014), independent of GA at birth. Elevated cord blood EPO levels (r = 0.182, p = 0.016) and GA at birth (r =  -0.236, p = 0.004) remained significant independent factors associated with the risk of IVH, when evaluated with stepwise logistic regression analyses. Cord blood IL-6, pH, and EONS were not associated with IVH. These relationships remained following correction for GA at birth (p = 0.027).

CONCLUSIONS

Our results suggest that elevation in cord blood EPO may predict newborns at risk for IVH, independent of fetal inflammatory status. Further studies are warranted to confirm this association.

Fatores de risco maternos associados à acidose fetal

OBJETIVOS: avaliar os fatores de risco maternos associados à acidose fetal. MÉTODOS: estudo tipo caso-controle composto por 188 recém-nascidos, sendo que 47 compuseram o grupo casos (pH de artéria umbilical <7,0) e 141 os de controles (pH de artéria umbilical <7,1 <7,3) nascidos imediatamente após cada caso. Consideraram-se fatores de inclusão: recém-nascidos de gestações únicas e sem malformação congênita. Analisaram-se variáveis maternas e fetais. Foram realizadas a Odds Ratio bruta e ajustada, teste t de Student, teste do qui-quadrado e análise multivariada através da regressão logística nãocondicional pelo método Enter. Assumiu-se como nível de significância estatística um p<0,05. RESULTADOS: no grupo de casos foi observado maior percentual de cesarianas, de recém-nascidos pré-termo, que apresentaram quase cinco vezes mais necessidade de cuidados intensivos e vinte cinco vezes mais chance de Apgar no 5º minuto <7. Não foram observadas associação entre os grupos e a apresentação fetal, idade materna, história de abortos anteriores, escolaridade materna e frequência ao pré-natal. Após a análise multivariada persistiram como fator de risco complicações relacionadas com a placenta e cordão. Os recémnascidos cujos partos associaram-se a complicações da placenta ou do cordão umbilical apresentaram três vezes mais chance de acidemia fetal. CONCLUSÕES: os recém-nascidos acidóticos estiveram relacionados à maior percentual de cesarianas, de prematuridade, necessidade de cuidados de tratamento intensivo e índice de Apgar <7 no 5º minuto. Após a análise multivariada, persistiram como fator de risco para acidemia fetal as complicações relacionadas ao descolamento prematuro de placenta e cordão umbilical.

Antenatal variables associated with severe adverse neurodevelopmental outcome among neonates born at less than 32 weeks

OBJECTIVE

To determine the association between antenatal factors and severe adverse neurodevelopmental outcome (ANDO) in preterm infants.

STUDY DESIGN

Neurodevelopmental follow-up was performed in a cohort of babies born at <32.0 weeks' gestation with birth weight <1500 grams between 1999 and 2006. Logistic regression analysis was used to relate obstetric, perinatal and neonatal ultrasonographic predictors to severe ANDO, defined as cerebral palsy or neurodevelopmental impairment, including sensory damage and adjusted development quotient <70.

RESULTS

88.6% (195/220) of surviving babies underwent follow up for a median of 24 months (range 12-96); 45 of them (23%) had ANDO, which was severe in 28 (14.3%). Abnormal ultrasonographic findings (intraventricular hemorrhage grades 3 or 4, periventricular leukomalacia, or ventriculomegaly) were observed in 18 cases (9.2%) and they were significantly associated with severe ANDO (OR 11.8 95% CI 4.0-34.0). Only gestational age at delivery (OR 0.80 95% CI 0.66-0.97), but not intrauterine infection, was independently related to severe ANDO. Infants with severe ANDO born before 28 weeks presented lower umbilical artery pH (7.24±0.1 vs 7.31±0.06, p=0.005) and a significantly higher rate of cesarean delivery (85.7% vs 50%, OR 6 95%CI 1.3-26.3, p=0.03) compared with infants without severe ANDO.

CONCLUSION

Gestational age at delivery and low umbilical artery pH at less than 28 weeks, but not intrauterine infection, are independent risk factors for severe ANDO in babies with birth weight <1500g.

Associations between serum cortisol, cardiovascular function and neurological outcome following acute global hypoxia in the newborn piglet

Perinatal asphyxia is a significant contributor to neonatal brain injury. However, there is significant variability in neurological outcome in neonates after global hypoxia-ischemia. The aims of this study were to identify which physiological response/s during global hypoxia-ischemia influence the severity of brain injury and to assess their relative importance. Hypoxia/hypercapnia was induced in 20 anaesthetized piglets by reducing the inspired oxygen fraction to 10% and the ventilation rate from 30 to 10 breaths per minute for 45 min. Neurological outcome was assessed using functional markers including cerebral function amplitude (via electroencephalography) and cerebral impedance, and the structural marker microtubule associated protein-2 by immunohistochemistry at 6 h post hypoxia. Significant variability in neurological outcome was observed following the constant hypoxia/hypercapnia insult. There was a high degree of variability in cardiovascular function (mean arterial blood pressure and heart rate) and serum cortisol concentrations in response to hypoxia. More effective maintenance of cardiovascular function and higher serum cortisol concentrations were associated with a better outcome. These two variables were strongly associated with neurological outcome, and together explained 68% of the variation in the severity of neurological outcome. The variability in the cardiovascular and cortisol responses to hypoxia may be a more important determinant of neurological outcome then previously recognized.

Clinical aspects of induced hypothermia in full term neonates with perinatal asphyxia

Moderate hypothermia is a novel neuroprotective therapy for full term neonates with severe perinatal asphyxia. Although the therapy appears to be safe, admission to a level III neonatal intensive care unit of these patients is justified. Potential complications include hypotension, tube obstruction due to sticky secretions, severe bradycardia, and thrombocytopenia. Furthermore, doses of commonly used drugs such as sedatives, anticonvulsants and antibiotics should be adjusted during hypothermia and on rewarming, and should be monitored carefully. Further studies aiming at optimizing onset, duration, and depth of hypothermia in neonates are necessary. Combination of hypothermia with drugs may further improve neuroprotection in asphyxiated full term neonates.

Interdisciplinary surveillance of intraventricular haemorrhage associated conditions in infants <1000 g

AIM

Intraventricular haemorrhage (IVH) causes some of the most adverse outcomes in infants with birthweight <1000 g. Incomplete antenatal steroids, acidosis, inflammation, postnatal transfer, delayed surfactant administration, hypothermia, hypotension, hypocapnia, persistent ductus arteriosus and pneumothorax are all associated with IVH. We hypothesized that prospective surveillance of these IVH-associated conditions decreases their frequency and thus the frequency of IVH.

METHODS

Cranial ultrasound was performed on days 1, 3, 7, 30 after birth and at discharge, and was assessed according to Papile. The incidence of IVH and IVH-associated conditions was monitored prospectively in all infants <1000 g born in our perinatal centre in 2005/2006, and obstetricians and neonatologists held monthly interdisciplinary review conferences to discuss the preventability of IVH-associated conditions (IVH surveillance). These data were compared to existing prospective data gathered during routine monitoring in 2004.

RESULTS

IVH (all grades) occurred in 29/86 extremely low birthweight (ELBW) infants during routine monitoring and in 12/89 ELBW infants during IVH surveillance (p = 0.007). IVH grades 3-4 dropped from 20% to 3.4% (p = 0.0006). There were significant differences in completeness of antenatal steroids (54% vs. 67%, p = 0.04) and timeliness in initial surfactant substitution (45% vs. 71%, p = 0.01). Most other IVH-associated conditions were reduced during IVH surveillance without reaching significance.

CONCLUSIONS

IVH is not always an inevitable disaster. Obstetricians and neonatologists can reduce its incidence by joint prospective surveillance of IVH-associated conditions.

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