The value of a scoring system for hypoxic ischaemic encephalopathy in predicting neurodevelopmental outcome

Elevated morphine concentrations in neonates treated with morphine and prolonged hypothermia for hypoxic ischemic encephalopathy

OBJECTIVES

Asphyxia and hypothermia may modify drug pharmacokinetics. We investigated whether analgesia with morphine in neonates with hypoxic ischemic encephalopathy undergoing prolonged moderate systemic hypothermia resulted in elevated serum morphine concentrations compared with normothermic infants.

PATIENTS AND METHODS

Infants from 1 center participating in a multicenter randomized study of moderate whole-body hypothermia after perinatal asphyxia (the Total Body Hypothermia Study) were randomly selected for treatment with hypothermia (n = 10) or for standard care on normothermia (n = 6). Hypothermia (33 degrees C to 34 degrees C) was started before 6 hours of age and maintained for 72 hours. All of the infants were treated with a continuous infusion of morphine-hydrochloride, with the rate adjusted according to clinical status. Serum morphine concentrations were determined at 6, 12, 24, 48, and 72 hours after birth.

RESULTS

Serum morphine concentrations at 24 to 72 hours after birth were (median [range]) 292 ng/mL (137-767 ng/mL) in the hypothermia-treated infants and 206 ng/mL (88-327 ng/mL) in the infants on normothermia, despite similar morphine infusion rates and cumulative doses. Morphine concentrations correlated with morphine infusion rate, cumulative dose, and treatment with hypothermia. Serum morphine concentrations reached a steady state after 24 hours in the normothermic infants but continued to increase throughout the assessment period in the hypothermia group. Morphine clearance was low in both groups: (median [range]) morphine clearance estimated from area under the curve was 0.69 mL/min per kg (0.58-1.21 mL/min per kg) in hypothermic group and 0.89 mL/min per kg (0.65-1.33 mL/min per kg) in infants on normothermia. Serum morphine concentrations >300 nL/mL occurred more often in the hypothermia group and when the morphine infusion rate was >10 microg/kg per h.

CONCLUSIONS

Infants with hypoxic ischemic encephalopathy have reduced morphine clearance and elevated serum morphine concentrations when morphine infusion rates are based on clinical state. Potentially toxic serum concentrations of morphine may occur with moderate hypothermia and infusion rates >10 microg/kg per h.

Prenatal exposure to mercury and neurobehavioral development of neonates in Zhoushan City, China

Exposure to hazardous Hg can adversely affect children's neurodevelopment. However, few data are available on either Hg levels in neonates and their mothers or the impact of prenatal exposure to Hg on neonates' neurobehavioral development in the Chinese population. Therefore, this study examined Hg levels in neonates and their mothers and the relationship between prenatal exposure to Hg and neonates' neurobehavioral development in Zhoushan City, Zhejiang Province, China. Between August and October 2004, 417 women who delivered their babies at Zhoushan Women's and Children's Health Hospital, an island city in east China were invited to take part in this study. A total of 408 complete questionnaires, 405 maternal hair samples, and 406 umbilical cord samples were collected. Neonatal behavioral neurological assessments (NBNA) were conducted for 384 neonates. The geometric mean (GM) of Hg level in cord blood was 5.58 microg/L (interquartile range: 3.96-7.82 microg/L), and the GM of maternal hair Hg level was 1246.56 microg/kg (interquartile range: 927.34-1684.67 microg/kg), a level much lower than other reported fish-eating populations, indicating Hg exposure in Zhoushan city is generally below those considered hazardous. However, according to the reference dose of Hg levels (RfD 5.8 microg/L) derived by EPA, 69.9% of newborns had levels at or above the RfD, an estimated level assumed to be without appreciable harm. There was a strong correlation between maternal hair and cord blood Hg levels (r = 0.82, P < 0.01). Frequency of fish consumption was associated with hair Hg (r = 0.48, P < 0.01) and cord blood Hg levels (r = 0.54, P < 0.01). Increased prenatal Hg exposure was associated with decreased behavioral ability for males (OR = 1.235, 95%CI of OR = 1.078-1.414, P < 0.001), but not for females. Our results provide some support for the hypothesis that there is neurodevelopmental risk for males from prenatal MeHg exposure resulting from fish consumption. But the findings of this study may be due to chance, and long-term follow-up research is needed to evaluate cumulative effects of exposure to mercury.

Long-term cognitive and behavioral consequences of neonatal encephalopathy following perinatal asphyxia: a review

Neonatal encephalopathy (NE) following perinatal asphyxia (PA) is considered an important cause of later neurodevelopmental impairment in infants born at term. This review discusses long-term consequences for general cognitive functioning, educational achievement, neuropsychological functioning and behavior. In all areas reviewed, the outcome of children with mild NE is consistently positive and the outcome of children with severe NE consistently negative. However, children with moderate NE form a more heterogeneous group with respect to outcome. On average, intelligence scores are below those of children with mild NE and age-matched peers, but within the normal range. With respect to educational achievement, difficulties have been found in the domains reading, spelling and arithmetic/mathematics. So far, studies of neuropsychological functioning have yielded ambiguous results in children with moderate NE. A few studies suggest elevated rates of hyperactivity in children with moderate NE and autism in children with moderate and severe NE.

CONCLUSION

Behavioral monitoring is required for all children with NE. In addition, systematic, detailed neuropsychological examination is needed especially for children with moderate NE.

Magnesium supplementation and perinatal hypoxia: outcome of a parallel group randomised trial in pregnancy

OBJECTIVE

To determine the effects of magnesium supplementation in pregnancy on the incidence of hypoxic-ischaemic encephalopathy (HIE).

DESIGN

A randomised double-blind placebo-controlled study.

SETTING

A Midwife Obstetric Unit and its two referral hospitals in Cape Town, South Africa.

POPULATION

A group of 4494 black pregnant women of low socio-economic status.

METHOD

Mothers, from the time of booking until delivery, were randomised to receive two identical tablets daily, containing either 128 mg slow-release magnesium stearate or lactose sugar.

MAIN OUTCOME MEASURES

Primary: The incidence of HIE. Secondary: The incidence of fetal heart rate decelerations, term Stillbirths, Low Apgar Scores, Meconium Aspiration Pneumonia.

RESULTS

The incidence of HIE (0.9%) was considerably less than anticipated (2%). There were 22 infants in the placebo group and 15 infants in the supplemented group (P = 0.279). The difference was not significant. Secondary outcomes such as late fetal heart rate decelerations (P = 0.002) and term stillbirths (P = 0.016) were reduced significantly in the supplemented group, but this finding needs further substantiation.

CONCLUSIONS

Magnesium supplementation did not reduce the incidence of HIE significantly, probably because the study was underpowered and compliance was relatively poor.

Mild hypothermia via selective head cooling as neuroprotective therapy in term neonates with perinatal asphyxia: an experience from a single neonatal intensive care unit

OBJECTIVE

The objective of this study was to determine the efficacy of mild hypothermia via selective head cooling as a neuroprotective therapy in term infants with perinatal asphyxia.

STUDY DESIGN

Full-term newborns who had 5 min Apgar scores <6, first arterial blood gas pH<7.10 or BD>15 mEq/l, and with the clinical signs of encephalopathy were enrolled within 6 h after birth. Patients were randomized to receive mild hypothermia treatment via selective head cooling for a total of 72 h or receive routine treatment as a control. Brain hypoxic-ischemic injury was quantified based on the head computed tomographic scan (CT scan) at postnatal age 5-7 days and a Neonatal Behavioral Neurological Assessment (NBNA) score at 7-10 days of life.

RESULTS

A total of 58 patients (30 hypothermia, 28 control) completed the study. Hypothermia was well tolerated in this study and attenuated the hypoxic-ischemic brain injury due to perinatal asphyxia. Head CT scan demonstrated moderate to severe hypoxic-ischemic changes in only 4/30 cases from the hypothermic group. In contrast, 18/28 cases in the control group showed moderate to severe hypoxic-ischemic changes (chi (2)=15.97, P<0.01). Brain hypothermia also significantly improved the NBNA score (32+/-2 in the hypothermic group vs 28+/-3 in the control group, P<0.01).

CONCLUSIONS

Our results suggest that selective head cooling may be used as a neuroprotective therapy in term neonates with perinatal asphyxia. A long-term follow-up study is needed to further validate the results of this study.

Neurodevelopmental outcome of infants with birth asphyxia treated with magnesium sulfate

BACKGROUND

A neuroprotective effect of MgSO(4) has been shown in some animal models of perinatal hypoxic-ischemic brain damage. The aim of the present paper was to determine whether postnatal MgSO(4) infusion (250 mg/kg per day i.v. for 3 days, in combination with dopamine) is safe in infants with severe birth asphyxia, and also observe effects on neurodevelopmental outcome at 18 months.

METHODS

Inclusion criteria were clinical history consistent with perinatal asphyxia; gestational age at least 37 weeks; 5 min Apgar score < or =6; failure to initiate spontaneous respiration within 10 min after birth; and symptoms of encephalopathy. On each day MgSO(4) was infused over 1 h in combination with dopamine (5 microg/kg per min). Changes in vital signs, clinical course of encephalopathy, laboratory variables, and adverse events were monitored. Infants were followed for 18 months.

RESULTS

Thirty infants were studied. Mean birthweight was 2878 g; mean gestational age, 39.6 weeks, and median 5 min Apgar score, 3. All required endotracheal intubation for resuscitation. Median age at MgSO(4) initiation was 5 h. All infants had moderate or severe hypoxic-ischemic encephalopathy. Mean serum Mg(2+) concentration remained at least 1.3 mmol/L. MgSO(4) caused no change in physiological variables including mean arterial pressure. Two infants died as neonates, while six of 28 survivors had severe neurodevelopmental disability at 18 months; the remaining 22 had no neurodevelopmental disability.

CONCLUSION

Postnatal infusion of MgSO(4) with dopamine caused no change in physiological variables. Deaths and severe sequelae were less frequent than in reported cases with the same grade of hypoxic-ischemic encephalopathy severity, and this treatment may improve neurodevelopmental outcome in infants with severe birth asphyxia.

Urinary S-100B concentrations in term and preterm infants at risk for brain damage

BACKGROUND

Elevated serum concentrations of S-100B, a 21-kDa protein expressed in astroglial cells, has been used to assess cerebral damage after head trauma, infection, ischemia, and perinatal asphyxia.

OBJECTIVE

As S-100B is eliminated by the kidneys, we investigated the feasibility of measuring S-100B in urine of newborns with severe perinatal asphyxia, and in very low birth weight (VLBW) preterm infants at risk for neurodevelopmental impairment.

METHODS

We first analyzed urine samples of 8 term or near-term newborns without major medical problems, followed by urine samples of 2 term newborns with severe birth asphyxia, and finally urine samples of 8 VLBW (gestational age 24-28 weeks) infants collected every 4 h for up to 10 days.

RESULTS

Urinary S-100B concentrations in 8 term or near-term newborns without major medical problems were consistently <1 microg/l. In 2 term newborns with severe asphyxia (Apgar 0/0/0 and 0/2/4) who subsequently had widespread cerebral damage on magnetic resonance imaging, peak urinary S-100B concentrations on the first day of life were 28.1 and 28.4 microg/l, respectively. In 5/8 VLBW infants, urinary S-100B was> microg/l in samples obtained on the first day of life (range 1.2-44.9 microg/l, median 6.8 microg/l). Peak S-100B in urine samples collected during the first 12 h of life were negatively related to gestational age (R(s)=-0.882, p=0.009). Three of the 8 preterm infants had peak urinary concentrations>0 microg/l but neither ultrasound signs of brain damage nor neurodevelopmental delay at 1 year corrected age.

CONCLUSIONS

The determination of urinary S-100B concentrations might be helpful in term infants with severe asphyxia, while high urinary S-100B concentrations in preterm infants are to be attributed to immaturity.

Changes of lactate, glucose, ionized calcium and glutamate concentrations in cephalic vein blood during brain hypothermia using extracorporeal membrane oxygenation (ECMO) in a newborn infant with hypoxic-ischemic encephalopathy

An asphyxiated infant with severe hypoxic-ischemic encephalopathy was treated by brain hypothermia using extracorporeal membrane oxygenation (ECMO). The brain hypothermia using ECMO maintained cardiopulmonary functions and stabilized brain temperatures by stably supply of the cooled blood to the brain. Moreover,we measured the levels of glucose, lactate, ionized calcium and glutamate in plasma. The comparison between these levels in the artery and in the cephalic vein, suggests that glucose, lactate, ionized calcium and glutamate might be used as markers of the effects of hypothermia therapy.

Clinical signs predict 30-month neurodevelopmental outcome after neonatal encephalopathy

OBJECTIVE

This study was undertaken to determine the value of a neonatal encephalopathy score (ES) and the presence of seizures for predicting 30-month neurodevelopmental outcome.

STUDY DESIGN

In a cohort study, 68 term newborn infants with encephalopathy were evaluated with an ES based on alertness, feeding, tone, respiratory status, reflexes, and seizure activity (range: 0-6). Seizures were noted as present or absent clinically. Significant cognitive deficits (Mental Development Index <70), motor disability (spastic triplegia/quadriplegia), or death were abnormal outcomes.

RESULTS

Twenty-two newborn infants (32%) had abnormal outcomes. With the use of maximum ES and presence of seizures from days 1 to 3 of life, 87% of newborn infants were correctly classified (area under receiver operating curve 0.93). By using ES and presence of seizures on day 1 only, 87% of newborn infants were correctly classified (area under receiver operating curve 0.89).

CONCLUSION

The severity of neonatal encephalopathy and the presence of seizures are valuable predictors of 30-month neurodevelopmental outcome, as early as the first day of life.

Encephalopathy as a predictor of magnetic resonance imaging abnormalities in asphyxiated newborns

Basal ganglia abnormalities on magnetic resonance imaging predict neurodevelopmental impairment in newborns with perinatal depression. We determined the value of a clinical encephalopathy score as a predictor of abnormal magnetic resonance imaging results in newborns with perinatal depression. We assigned a neonatal encephalopathy score to 101 newborns. The encephalopathy score, based on alertness, feeding, tone, respiratory status, reflexes, and seizure activity, was assigned once daily. The maximum score from the first 3 days of life was compared with abnormal magnetic resonance imaging results present globally or solely in the basal ganglia.Eighty-one percent of patients manifested abnormalities on any magnetic resonance imaging sequence, and 37% manifested abnormalities in the basal ganglia alone. The encephalopathy score correlated well with magnetic resonance imaging abnormalities in the basal ganglia (Spearman Rho = 0.335, P < 0.0001). Newborns with mild and severe encephalopathy had likelihood ratios of 0.41 and 7.4, respectively, for abnormal basal ganglia magnetic resonance imaging results. Newborns with moderate encephalopathy (composing 47% of the cohort) manifested basal ganglia abnormalities with a likelihood ratio of 0.785. Severe clinical encephalopathy correlates with abnormal basal ganglia magnetic resonance imaging results, and mild encephalopathy correlates with a normal magnetic resonance imaging result. However, standard clinical criteria do not alter the prior risk of abnormal basal ganglia magnetic resonance imaging results for newborns with moderate encephalopathy.

Cranial ultrasound as a predictor of outcome in term newborn encephalopathy

As part of a patient-based case-control study of newborn encephalopathy, we examine the cranial ultrasound results of 212 patients to determine the validity of ultrasound in predicting an adverse outcome. Forty-six (22%) patients died or developed cerebral palsy (adverse outcome) by 2 years of age. On the basis of clinical decision, 125 (60%) patients had an ultrasound before 72 hours of age; of these, 29% had an adverse outcome. The resistive index is the primary measure of interest, with a value of 0.55 or less considered abnormal. Infants with an abnormal resistive index are 8.8 times (P < 0.001) more likely to have an adverse outcome than those with a normal result. The positive predictive value of an abnormal resistive index was 71%. The results are similar for the subgroup with intrapartum hypoxia and the subgroup that had ultrasound performed before 24 hours of age. It is clear that resistive index results cannot be used in isolation, although they may have a place, in combination with other factors, in the counseling of parents and, cautiously, in the clinical management of patients.

Long-term developmental outcome of asphyxiated term neonates

Asphyxia remains one of the main causes of later disability in term infants. Despite many publications identifying possible predictors of outcome in this population of interest, little is known of the long-term developmental outcome of asphyxiated term neonates. Observational studies have largely focused on short-term outcomes, with an emphasis on significant neurologic sequelae and intellectual impairments. This article reviews the literature that has described the developmental outcome of asphyxiated term newborns. As part of this review, we have also highlighted the evolution of the definition of asphyxia and delineated appropriate markers that should be used in future research on this population.

Neonatal neurologic prognostication: the asphyxiated term newborn

The pediatric neurologist is often requested to predict the neurologic outcome in an uncertain situation. A common and problematic clinical setting in which this occurs is the asphyxiated term newborn. This report reviews the predictive tools available for prognostication in this situation and formulates a practical paradigm that the authors hope will improve predictive accuracy and lessen uncertainty in this setting.

Newborn assessment and long-term adverse outcome: a systematic review

The medical literature was searched for publications between 1966 and September 1997 for data on the association of Apgar score, umbilical blood pH, or Sarnat grading of encephalopathy with long-term adverse outcome. Odds ratios for these associations were combined to calculate common odds ratios with 95% confidence intervals. Our search identified abstracts of 1312 studies and 81 articles with sufficient numeric data to formulate contingency tables. Forty-two of these qualified for inclusion in our meta-analysis. The strongest associations in the prediction of neonatal death were found by comparing umbilical artery pH <7 with pH >/=7 (common odds ratio 43; 95% confidence interval 15-124) and by comparing Sarnat grade III with grade II (common odds ratio 24; 95% confidence interval 13-45). In the prediction of cerebral palsy, the strongest associations were found for Sarnat grade III versus grade II (common odds ratio 20; 95% confidence interval 6-70) and for 20-minute Apgar score 0 to 3 versus 4 to 6 (common odds ratio 15; 95% confidence interval 5-50).