[Blood lactate measurments as a diagnostic and prognostic tool after birth asphyxia in newborn infants with gestational age > or = 34 gestational weeks]

Blood lactate at birth as result of activated anaerobic glycolysis is a marker of perinatal asphyxia.

AIM

To evaluate the dynamics of blood lactate, pH and base excess (BE) as a tool for assessing the severity of fetal hypoxia and predicting neonatal outcome.

METHODS

79 neonates (> or = 34 gestational weeks) were included and followed up until discharge: 43 with pathologic fetal hearth rate patterns and/or 1-minute Apgar score < 7 ("asphyxia group"); 36 without obstetric or clinical signs of asphyxia (control group). Samples from umbilical artery (u.a.), capillary blood at 2h and 12-24 h after birth were analyzed for blood lactate, pH and BE.

RESULTS

Lactate value (u.a.) was significantly higher (5.3 +/- 3.4 mmol/l), pH and BE were lower (7.29 +/- 0.05 and -14.1 +/- 5.9 mmol/l) in the "asphyxia group" compared to the control group (2.7 +/- 1.2 mmol/l, 7.29 +/- 0.05 and -5.9 +/- 3.3 respectively). The 2 h lactate-values increased significantly in infants with asphyxia (6,.7 +/- 4.7) compared to the controls (3.2 +/- 1.1), the 12-24 h values were reduced in the main group (4.6 +/- 1.5) and without changes in the controls (3.2 +/- 0.88). Values of pH and BE at 2 h and 12-24 h increased progressively in both groups without significant differences between them. Hypoxic-ischemic encephalopathy (HIE) stage II-III was observed in infants with u.a. pH < 7.05, BE < -15 if u.a. lactate was high and progressively increased in next 2 h.

CONCLUSIONS

High u.a. lactate values correlate with low pH and BE and is a reliable tool for assessing the severity of fetal asphyxia. Increasing lactate concentration after birth is better predictor of severe HIE.

The influence of clinical and anthropometric parameters on the serum levels of the endothelin-1 in pregnant women and their newborns

Pregnancy induced hypertension (PIH) is major contributor to maternal death in developing countries. Endothelin-1 (ET-1) is the most potent vasoconstriction agent known and its serum levels are increased in PIH. Therefore it is important to elucidate maternal and neonatal factors which influence endothelin-1 serum levels. 100 pathological pregnancies and 88 controls were analyzed for blood endothelin-1 and their anthropometric and clinical data were collected. In maternal blood ET-1 levels were strongly predicted by diagnosis, therapy and BMI, while umbilical cord ET-1 levels were strongly predicted by gestational age, therapy and delivery termination. Positive correlation between BMI and ET-1 levels suggest that obese pregnant women have increased risk for cardiovascular diseases. Inverse relationship between Apgar and umbilical ET-1 indicates that ET-1 could be considered as a prognostic marker in cases of neonatal asphyxia.

Serum S100B and neuron-specific enolase levels in normothermic and hypothermic infants after perinatal asphyxia

AIM

Serum S100B and neuron-specific enolase (NSE) levels are elevated after perinatal asphyxia, but the influence of hypothermia on these proteins has not been previously reported. The aim of this study was to evaluate the effect of systemic hypothermia on these protein levels after perinatal asphyxia, time course, and association with perinatal factors and neurodevelopmental outcome at 2 years of age.

METHODS

Serum S100B and NSE levels were measured at fixed time points in asphyxiated infants treated with standard intensive care on hypothermia (HT: n = 13) or normothermia (NT: n = 11).

RESULTS

Serum S100B and NSE levels were grossly elevated in both HT and NT groups. Compared with the values at 6 h of age, S100B values decreased over time in both groups (NT: p = 0.002, HT: p = 0.04). Serum S100B values were lower in HT infants compared with those in NT infants (p = 0.047 at 48 h). Serum S100B and NSE values were significantly higher in infants who died or developed severe neurological impairment (S100B, p < 0.05 at all time points; NSE, p = 0.036 at 24 h of age).

CONCLUSION

Both NSE and S100B levels are highly elevated following asphyxia. Serum S100B levels were lower in the HT group and strongly correlated with the neurodevelopmental outcome.

Cardiac troponin I concentrations in neonates with hypoxic-ischaemic encephalopathy

AIM

Myocardial dysfunction is a frequent sequel of perinatal asphyxia. Cardiac troponin I (cTnI) is a marker of myocardial injury and a surrogate marker of myocardial dysfunction in adults, but there are few data in neonates. Our aim was to compare serum cTnI concentrations with clinical severity of encephalopathy and with duration of inotropic support in asphyxiated neonates.

METHODS

Retrospective study of 60 neonates admitted with hypoxic-ischaemic encephalopathy (HIE). cTnI concentrations measured within 36 h of birth were compared with clinical grade of HIE (Sarnat-Sarnat classification) and with duration of inotropic support.

RESULTS

Serum cTnI concentrations and duration of inotropic support were significantly greater with increasing severity of HIE. Median (95% CI) cTnI concentrations were 0.04 μg/L (0.02-0.07 μg/L) in grade 1 HIE, 0.12 μg/L (0.08-0.20 μg/L) in grade 2 HIE and 0.67 μg/L (0.41-1.35 μg/L) in grade 3 HIE. Median (95% CI) duration of inotropic support required was 0 h (0-24 h) in grade 1 HIE, 28 h (0-118 h) in grade 2 HIE and 48 h (0-140 h) in grade 3 HIE.

CONCLUSION

In asphyxiated neonates, cTnI concentrations within 36 h of birth correlate strongly with clinical grade of HIE and with duration of inotropic support. Early cTnI concentrations may provide a useful proxy marker for the anticipated severity of myocardial dysfunction.

Hemostasis and platelet dysfunction in asphyxiated neonates

Hemostasis is the balance between bleeding and clotting and includes coagulation and fibrinolysis with platelet interactions. Despite developmental hemostasis that describes the major differences between neonates and older children and adults, neonates do not have increased bleeding or clotting unless clinical situations disturb the "balance." Perinatal asphyxia alters the balance of hemostasis, resulting in abnormalities that may result in bleeding and thrombosis. The following discussion will describe normal hemostasis, laboratory measures of hemostasis, developmental hemostasis, and the effects of asphyxia on hemostasis.

[Multicenter clinical study on umbilical cord arterial blood gas parameters for diagnosis of neonatal asphyxia]

OBJECTIVE

To obtain the normal range of statistics of umbilical artery blood gas parameters of the newborns for diagnosis of neonatal asphyxia.

METHODS

From March 2008 through September 2009, 17 978 singleton term appropriate for gestational age (AGA) or larger than gestational age (LGA) newborns in six hospitals of five provinces/autonomous regions were consecutively enrolled in this prospective study. The normal ranges of umbilical artery blood gas parameters were obtained from 17 645 newborns with 1 min Apgar score ≥ 8. The correlations between umbilical artery blood pH, BE and prenatal high-risk factors, Apgar scores, and organ damage were analyzed. The diagnostic criteria for asphyxia included the following: (1) Having high-risk factors that might cause asphyxia; (2) 1 min Apgar score ≤ 7 (the respiratory depression must be present); (3) At least one organ showed evidence of hypoxic damage; (4) Other causes of low Apgar score were excluded. The study focused on the distributive characteristics of umbilical artery blood pH (clinically corrected by Eisenberg formula) and BE values of the asphyxiated and non-asphyxiated cases in low Apgar score group, as well as the sensitivity and specificity of different selected pH and BE threshold spots within their distributing ranges.

RESULTS

Among the 17 978 singleton term AGA or LGA newborns, the statistically normal range of umbilical artery blood pH, BE for the 17 645 cases with 1 min Apgar scores ≥ 8 were 7.20 ± 0.20 (x(-) ± 1.96 s) and -7.64 ± 10.02 (x(-) ± 1.96 s), respectively. The pH well correlated positively with BE (r = 0.734, P < 0.01). The umbilical artery blood pH and BE values correlated positively with the Apgar scores. The umbilical artery blood pH and BE values correlated negatively with organ damage (r = 1, the P values = 0.000 for both). Among the 333 low Apgar score cases, the umbilical artery blood pH corrected values and BE values of the asphyxiated group (163 cases) were 7.011 ± 0.09 (x(-) ± s) and -14.98 ± 2.99 (x(-) ± s), being lower than 7.18 ± 0.07 (x(-) ± s) and -8.56 ± 4.68 (x(-) ± s) of the non-asphyxiated group (170 cases) respectively (t = 14.3, 8.79, P values < 0.001). The distributing ranges of the umbilical artery blood pH corrected values and BE values of the asphyxiated group were < 7.00- < 7.20 and < -10- < -18, respectively. Within the above ranges, none of selected spots with both high sensitivity and high specificity was found.

CONCLUSIONS

The statistically normal range of the umbilical artery blood pH and BE for the newborns was 7.20 ± 0.20 (x(-) ± 1.96 s) and -7.64 ± 10.02 (x(-) ± 1.96 s) respectively. Owing to individual differences and the measured blood pH should be clinically corrected, the statistical threshold was not fully equal to the clinicopathological threshold. The pathological threshold of pH or BE for neonatal asphyxia is a range rather than a fixed point. The distributing range of the umbilical artery blood pH clinically corrected values and BE values for neonatal asphyxia were < 7.00- < 7.20 and < -8- < -18, respectively. In the presence of the other four indexes for diagnosing neonatal asphyxia, the blood gas index should be used flexibly in the above ranges.

[Effect of Astragalus injection on the signal conduction of neonatal postasphyxial-serum induced human renal tubular cell injury]

OBJECTIVE

To investigate, from cytoprotein and molecular levels, the action mechanism of astragalus injection (ASI) on the signal conduction of human renal tubular cells (HK-2) injury induced by neonatal postasphyxial-serum (NPS), whether it is through activating the nuclear factor kappaB (NF-kappaB) signaling pathway.

METHODS

Taking HK-2 as the target cell and the 20% NPS as the attacking factor, the experiment was conducted by dividing the target cells into two groups before attacking, the blank control group and the ASI pretreated group. The nuclear translocation of NF-kappaB was detected by confocal microscopy with indirect immunofluorescence stain, and the amount of NF-kappaB inhibitor subunit (I-kappaBalpha) was detected by Western blot before attacking. The detections were repeated at various time points in the experiment, i.e., 15 min, 1 h and 2 h after attacking, respectively.

RESULTS

Before attacking, the nuclear translocation of NF-kappaB and the amount of I-kappaBalpha were not different in the two groups. But the former increased and the latter decreased significantly in the ASI group at all the time points after attacking with the topmost changes presented at 1 h after attacking, and significantly different to those in the control group at corresponding time

CONCLUSION

ASI pretreatment could inhibit the activation of NF-kappaB induced by postasphyxial-serum.

[Influence of diazoxide on mitochondrial apoptosis in human renal tubular cells induced by serum obtained from neonates with asphyxia]

OBJECTIVE

To study the influence of diazoxide on mitochondrial apoptosis pathway of human renal proximal tubular cells (HK-2 cells).

METHODS

Cultured HK-2 cells were inoculated on 6-well plates, according to stochastic tables law, and they were divided into normal serum-treated group (NSTG) , post-asphyxial serum treatment group (PSTG), and post-asphyxial serum and diazoxide treatment group (PSDTG). The serum from neonates 24 hours after asphyxia in a dilution of 20% (volume fraction) was used for challenge. Diazoxide in a final concentration of 100 mol/L, was used for intervention. The expression of caspase-3 was detected by immunohistochemical method. The translocation rate of Omi/HtrA2 and mitochondria membrane potential were determined by indirect immunofluorescence and confocal microscopy.

RESULTS

Compared with that of NSTG, the expression of caspase-3 absorbance (A) value of HK-2 cells in PSTG was significantly increased (25.19 + or - 3.33 vs. 13.63 + or - 1.89, P<0.01), the translocation rate of Omi/HtrA2 of HK-2 cells in PSTG was significantly increased [(56.01 + or - 5.30)% vs.(37.59 + or - 5.60)%, P<0.01], mitochondrial membrane red/green fluorescence intensity ratio was decreased significantly (0.79 + or - 1.42 vs. 1.82 + or - 0.23, P<0.01). Compared with the PSTG, the expression value of caspase-3 of HK-2 cells in PSDTG was significantly decreased (20.17 + or - 2.19), the translocation rate of Omi/HtrA2 of HK-2 cells in PSDTG was significantly decreased [(46.91 + or - 2.70)%], and mitochondrial membrane red/green fluorescence intensity ratio increased significantly (1.47 + or - 0.14), but did not recover to the same degree as that of the NSTG (all P<0.01).

CONCLUSION

The diazoxide may reduce the expression of caspase-3, intracellular translocation of Omi/HtrA2, and stability of mitochondrial membrane potential, thereby significantly alleviates HK-2 cells injury induced by post-asphyxial-serum of neonate.

[Plasma levels of N-terminal pro-brain natriuretic peptide and glycogen phosphorylase isoenzyme BB in neonates with asphyxia complicated by myocardial injury]

OBJECTIVE

To investigate the changes and the clinical significance of N-terminal pro-brain natriuretic peptide (NT-proBNP) and glycogen phosphorylase isoenzyme BB (GPBB) levels in neonates with asphyxia complicated by myocardial injury.

METHODS

Sixty-four neonates with asphyxia (39 mild, 25 severe) were enrolled. Of the 64 neonates, 30 had myocardial injury and 34 did not develop myocardial injury. Twenty-five healthy neonates served as a control group. Plasma levels of NT-proBNP and GPBB were measured using ELISA. Myocardial enzymes and cardiac troponin I were stimultaneously measured, and electrocardiography and chest radiographs were obtained.

RESULTS

The plasma levels of NT-proBNP and GPBB in neonates with myocardial injury were significantly higher than those in neonates without myocardial injury and in the control group (P<0.01). The neonates with severe asphyxia had significantly increased plasma NT-proBNP and GPBB concentrations compared to those with mild asphyxia and the control group (P<0.01). Spearman rank correlation analysis showed that plasma NT-proBNP level was positively correlated with plasma GPBB level in neonates with asphyxia. Plasma levels of NT-proBNP and GPBB were also positively correlated with plasma levels of CK-MB, CK and LDH (P<0.01).

CONCLUSIONS

Both NT-proBNP and GPBB can be used as biomarkers of myocardial injury in neonates with asphyxia. The measurement of plasma NT-proBNP and GPBB levels was useful in early identification of myocardial injury and severity evaluation in neonates with asphyxia.

Electrolyte status in birth asphyxia

OBJECTIVE

To study electrolyte status in asphyxiated newborns of different severity in early neonatal period and compare with controls.

METHODS

Sodium, potassium and total calcium levels were estimated in the serum samples of asphyxiated newborns of different severity and control group immediately after birth.

RESULTS

Mean serum sodium level was significantly lower (122.1 +/- 6.0 mEq/L vs 138.8 +/- 2.7 mEq/L; P < 0.001), mean serum potassium was higher (5.05 +/- 0.63 mEq/L vs 4.19 +/- 0.40 mEq/L; P < 0.001) and mean serum calcium level was found lower (6.85 +/- 0.95 mg/dl vs 9.50 +/- 0.51 mg/dl; P < 0.001) in cases than controls. Among cases, a strong positive linear correlation was found between the serum sodium, serum calcium levels and their Apgar scores, between sodium levels and total calcium levels and significant negative linear correlation between Apgar scores and serum potassium level.

CONCLUSION

Among cases, hyponatremia and hypocalcemia developed early and simultaneously and the decrease in their serum levels was directly proportional to each other and to the degree of asphyxia. Though, mean potassium level was within the normal limit, the value was higher among cases than controls and directly proportional to asphyxia.

Cord blood brain derived neurotrophic factor: diagnostic and prognostic marker in fullterm newborns with perinatal asphyxia

This prospective case control study was designed to evaluate cord blood brain derived neurotrophic factor level in full term newborns with perinatal asphyxia as a marker of central nervous system insult and predictor of severity of hypoxic ischemic encephalopathy, with follow up of its level during the reperfusion phase. The study included twenty fullterm neonates with perinatal asphyxia (cases) and twenty controls. Cord blood samples were obtained at birth and peripheral blood samples at 72 h postnatal from cases only. Plasma brain derived neurotrophic factor level was measured using enzyme linked immunosorbent assay. The clinical severity of encephalopathy was graded based on Sarnat and Sarnat staging. Cord Plasma brain derived neurotrophic factor level was significantly increased among cases compared to controls. Among cases, brain derived neurotrophic factor level at delivery and after 72 h significantly correlated with the severity of encephalopathy according to Sarnat staging being higher as severity increases. Brain derived neurotrophic factor level significantly increased after 72 h of life compared to its level at delivery among cases. Brain derived neurotrophic factor levels at delivery and at 72 h postnatal were predictors of severe Sarnat stage and poor outcome. We concluded that brain derived neurotrophic factor level as a marker of central nervous system insult is increased in full term newborns with perinatal asphyxia. It can serve as an indicator for the severity of encephalopathy and adverse outcomes.

Activated protein C resistance in cord blood from healthy and complicated newborns

OBJECTIVES

Newborns are susceptible to thrombosis secondary to the immature hemostatic system and maternal and fetal complications. The contribution of activated protein C resistance (APCR) to thrombosis tendency has not yet been established. This study was conducted to investigate the effects of maternal and fetal complications on APCR levels.

METHODS

APCR levels were determined in cord blood from healthy term infants and compared with those in healthy preterm and complicated neonates as well as that in adult venous blood.

RESULTS

The mean value of APCR in cord blood from healthy term infants (166 +/- 40 s) was not significantly different from that in adult venous blood (173 +/- 40 s). No significant differences in the mean cord blood APCR values were observed between healthy term and preterm infants, infants with vaginal and cesarean delivery, infants from preeclamptic and non-eclamptic mothers, and infants with or without perinatal asphyxia. The activity levels of protein C, protein S, and antithrombin III were not significantly different between these groups except for lower levels in preterm babies.

CONCLUSIONS

The level of APCR in cord blood is comparable to that in adults and not influenced by maternal and fetal complications. It appears that APCR does not contribute to the thrombotic tendency in newborns.

Nucleated red blood cell and platelet counts in asphyxiated neonates sufficient to result in permanent neurologic impairment

OBJECTIVE

Recent research has suggested that a nucleated red blood cell (NRBC) count >or=26 per 100 white blood cells (%) or the development of a platelet count <or=100,000 per mm(3) within five days of birth is characteristic of neonates who have experienced acute birth asphyxia.

STUDY DESIGN

Study cases were from the population defined in a prior publication (Prenat Neonat Med 1997;2:286). The impaired neonates were separated into three groups: group 1, persistent non-reactive fetal heart rate (FHR) pattern from admission until delivery; group 2, reactive FHR pattern on admission followed by a tachycardia, non-reactivity, repetitive variable or late decelerations, and usually a loss of variability; group 3, cases with a reactive FHR pattern on admission followed by a sudden, rapid and sustained deterioration of the FHR usually in response to a hypoxic sentinel event that lasted until delivery or a bradycardia on admission. The FHR pattern in group 3 is considered most consistent with acute birth asphyxia. We then examined these FHR groups with respect to the presence of hematologic injury. Chi-square testing was used to describe differences among the study populations.

RESULTS

Of the original 52 cases, sufficient hematologic data were available for 47. Of these, the proportion of cases with NRBC >or=26% was: group 1, 10/21 (47.6%); group 2, 0/14 (0%); group 3, 0/12 (0%). Those with a platelet count <or=100,000 per mm(3): group 1, 11/21 (52.4%); group 2, 2/14 (14.3%); group 3, 0/12 (0%). Group 1 was significantly more likely to have an NRBC count >or=26% than group 3 (p = 0.0135). A platelet count <or=100,000 per mm(3) within five days of birth was also significantly more likely to be encountered in group 1 as compared with group 3 (p = 0.0072).

CONCLUSION

In cases of acute birth asphyxia, hematologic injury was infrequently encountered. Our findings suggest that a neonatal NRBC count >or=26% and/or a platelet count <or=100,000 per mm(3) within five days of birth is inconsistent with acute birth asphyxia.

[Disorders of the acid-basic balance in the post-hypoxic suffering at newborn babies]

The study aims to asses the acid-basic disorders and the blood gasses in the blood of the umbilical cord and their correlation with the evolution of the newborn baby in the maternity hospital.

MATERIAL AND METHOD

157 newborns with perinatal asphyxia hospitalized (2002-2005) in the Maternity of "Sf. Apostol Andrei" Clinical Emergency Hospital of Galaţi, following-up the gestation age, the Apgar score, the risk factors of perinatal asphyxia, the pH in the cord and the evolution of the blood gasses in the cord, the start and evolution of neurologic disorders.

RESULTS

The main risk factors for the asphyxia production: prematurity (64% of the cases and 25% of the cases with gestation age below 30 weeks), HTA induced in pregnancy, IUGR 39.4%. The Apgar score at one minute: values between 0-3 (40.8% cases), progressively decreasing to 20 minutes in 1.3%. 50% of the new born babies showed severe acidosis in the cord: pH > 6, 9, hypoxia in the cord blood was of 75%. The neurologic disorders started from the birth in all cases, with evolution to decease in 25.5% of the cases, higher incidence in prematures and a significant correlation with the pH in the cord.

[Role of pH value of umbilical artery blood in neonatal asphyxia]

OBJECTIVE

To study the role of pH value of umbilical artery blood in the diagnosis and the assessment of prognosis of neonatal asphyxia.

METHODS

A total of 140 single term newborn infants who were found abnormal by the fetal electrocardiogram monitoring were enrolled. The pH value of umbilical artery blood was measured immediately after birth. The Apgar score was performed 1 minute and 5 minutes after birth. The infants with the Apgar score<or=7 (n=62) were transferred to the pediatric ward for further management after resuscitation. Serum CTnI content was determined 24 hrs after birth.

RESULTS

pH value of umbilical artery blood was positively correlated to 1 min and 5 min Apgar scores (r=0.513 and 0.478 respectively; p<0.01). There were significant differences for the umbilical pH value in infants with different Apgar scores (p<0.01). Serum CTnI content was negatively correlated to 1 min and 5 min Apgar scores (r=-0.614 and -0.569 respectively; p<0.01). The infants with umbilical artery pH value of more than 7.2, 7.0-7.2 and less than 7.0 had serum CTnI contents of 31.82+/-8.63, 53.24+/-11.18 and 79.36+/-18.51 ng/L, respectively (p<0.01). There was a negative correlation between umbilical artery pH value and serum CTnI content (r=-0.578, p<0.01). The incidence of organ injuries increased significantly with decreasing Apgar scores (p<0.05) and showed a negative correlation with 1 min and 5 min Apgar scores (r=-0.548 and -0.496 respectively; p<0.01). The infants with umbilical artery pH value of more than 7.2, 7.0-7.2 and less than 7.0 had the incidence of organ injuries of 36.4%, 60.0% and 83.3%, respectively (p<0.05). There was a negative correlation between umbilical artery pH value and the incidence of organ injuries (r=-0.578, p<0.05).

CONCLUSIONS

Umbilical pH value correlates with Apgar score and may serve as sensitive indexes together with Apgar score for the diagnosis of neonatal asphyxia. Umbilical pH value is useful in the assessment of severity and prognosis of neonatal asphyxia.

[Activin A as a possible marker for hypoxia and intraventricular haemorrhage in newborns]

The article presents general information about activin A, a glycoprotein that belongs to the transforming growth factor beta superfamily. Structure, mechanism and role of activin as a possible marker of hypoxia and intraventricular haemorrhage were described.

[Relationship between brainstem auditory evoked potential and serum neuron-specific enolase in neonates with asphyxia]

OBJECTIVE

To study the correlation between brainstem auditory evoked potential (BAEP) and serum neuron-specific enolase (NSE) in neonates with asphyxia and explore the role of NSE in the evaluation of hearing impairment following asphyxia.

METHODS

Fifty-two term neonates with asphyxia, including 38 cases of simple asphyxia (mild: 23 cases; severe: 15 cases) and 14 cases of asphyxia complicated by hypoxic-ischemic encephalopathy (HIE), were enrolled. In the double-blind trial, BAEP and NSE were simultaneously detected 7 days after birth. The patients who did not pass BAEP test received another BAEP and NSE examinations 3 months after birth. Thirty healthy term neonates served as normal control group.

RESULTS

Of the 52 neonates with asphyxia, 50.0% and 21.2% of patients failed the initial and the second BAEP tests, respectively. The detection rates of BAEP anomalies in the simple severe asphyxia group in the initial and the second tests (63.3% and 26.3%, respectively) were significantly higher than those in the simple mild asphyxia group (36.9% and 5.9%, respectively)(P<0.05). The neonates with asphyxia complicated by HIE showed a higher detection rate of BAEP anomalies in the second test compared with the asphyxiated neonates without HIE (31.3% vs 16.7%; P<0.05). Mean serum NSE levels in asphyxiated neonates were significantly higher than those in normal controls (<0.01). There were significant differences in serum NSE levels between the neonates with mild and severe asphyxia (26.70+/-2.34 microg/L vs 17.18+/-3.16 microg/L; P<0.01). The asphyxiated neonates with HIE had serum NSE levels similar to the simple severely asphyxiated neonates. Serum NSE levels in patients who failed the initial BAEP test were significantly higher than those who passed the test (25.69+/-4.12 microg/L vs 17.15+/-3.09 microg/L; <0.01). Serum NSE levels had a positive correlation with wave V reaction threshold detected in the BAFP test (<0.05).

CONCLUSIONS

The serum level of NSE is closely correlated with BAEP, and it may be useful to the evaluation of the hearing impairment and the outcome in neonates with asphyxia.

[Role of serum from asphyxiated neonates in the inducement of human renal tubular cell adhesion to neutrophils]

OBJECTIVE

To study the role of serum from asphyxiated neonates in the inducement of human renal proximal tubular epithelial cells (HK-2) adhesion to neutrophils and possible mechanisms.

METHODS

HK-2 cells were cultured randomly with 20% serum from neonates (1, 3, and 7 days after asphyxia), pyrrolidine dithiocarbamate (PDTC) or placebo. The activity of myeloperoxidase (MPO), an indicator of adhesion ability of HK-2 cells to neutrophils in suspensions, was detected by the biochemistry assay. Intercellular adhesion molecule-1 (ICAM-1) and nuclear factor-kappaB (NF-kappaB) of HK-2 cells were examined with the immunohistochemical staining.

RESULTS

The expression of MPO in the post-asphyxial 1-day serum treatment group were significantly higher than that in the PDTC treatment and the control groups as well as the post-asphyxial 3 and 7-day serum treatment groups (P<0.01). The expression of ICAM-1 and NF-kappaB in the post-asphyxial 1-day serum treatment group was also significantly higher than that in the other groups (P<0.01).

CONCLUSIONS

Serum from asphyxiated neonates can induce HK-2 cell adhesion to neutrophils, possibly through activating NF-kappaB and increasing the synthesis and expression of ICAM-1 on the surface of renal tubular epithelial cells.

Consequences of neonatal resuscitation with supplemental oxygen

There has been considerable controversy surrounding the optimal inspired oxygen concentration for resuscitation of term and preterm infants. We have developed a rat pup model to quantify both physiologic and biochemical parameters associated with normoxic vs. hyperoxic resuscitation. We have confirmed existing human data that hyperoxic resuscitation of rat pups is associated with a significant delay in onset of spontaneous respiratory efforts. Both 40% and 100% inspired oxygen delayed onset of respiratory activity when compared to 21% oxygen. We have also documented, in the rat pup model, that hyperoxic resuscitation is associated with reduced levels of glutathione at 24 hours post resuscitation. The implications of these and other findings for human infants are that term asphyxiated babies can be safely resuscitated in 21% oxygen and that supplementary oxygen can be reserved for non-responders. In contrast, resuscitation of extremely low gestational age infants does appear to require an initial low inspired oxygen concentration (eg, 30%) with subsequent pulse oximetry titration to optimize oxygenation status.

Fetal electrocardiographic monitoring during labor in relation to cord blood levels of the brain-injury marker protein S-100

BACKGROUND

Cord artery protein S-100 levels at birth are potential markers of brain damage after asphyxia. Our aim was to investigate if S-100 levels were elevated in neonates with indirect signs of asphyxia during birth. S-100 levels in cord blood were studied in relation to cardiotocography (CTG) and fetal electrocardiography (FECG) changes during birth and to acidemia in umbilical blood.

MATERIAL AND METHODS

This case-control study was performed in parallel to a large randomized controlled trial (RCT) studying FECG at birth. Protein S-100 samples were collected from 103 neonates at birth and related to the CTG and ECG changes during labor and to pH in umbilical blood.

RESULTS

Protein S-100 was significantly higher in neonates with umbilical artery blood pH<or=7.05, compared to neonates with pH>7.05. Furthermore, neonates with preterminal CTG patterns showed increased S-100 levels compared to neonates with normal CTG. Neonates having significant CTG and ECG changes, leading to intervention according to clinical guidelines, showed significantly higher S-100 levels compared to neonates without such indication of intervention.

CONCLUSION

A relation exists between S-100 in umbilical blood at birth, acidosis and pathological patterns in CTG and FECG during labor.

[Serum levels of homocysteine and folate in neonates with asphyxia]

OBJECTIVE

To determine whether serum homocysteine and folate levels are correlated with the occurrence of neonatal asphyxia and to study the effects of gender and gestational age on serum homocysteine and folate levels.

METHODS

Thirty-five neonates with mild asphyxia (19 males and 16 females) and 40 normal neonates (control group,18 males and 22 females) were enrolled in this study. The asphyxia and the control groups consisted of 10 and 11 cases of preterm infants respectively. Serum homocysteine levels were measured using ELASA. Serum folate levels were measured using radioimmunity assay.

RESULTS

Serum homocysteine level (14.66+/-2.61 micromol/L vs 7.55+/-0.50 mumol/L; P<0.05) was significantly higher and serum folate level (2.47+/-0.24 ng/mL vs 3.28+/-0.28 ng/mL; P<0.05) was significantly lower in the asphyxia group than that in the control group. There were no significant differences in serum levels of homocysteine and folate between males and females either in the asphyxia group or the control group. The asphyxiated neonates born at premature showed increased serum homocysteine level compared with the full-term neonates with asphyxia (21.25+/-5.01 micromol/L vs 12.34+/-2. 01 micromol/L; P<0.05).

CONCLUSIONS

The increased serum homocysteine level and decreased serum folate level are correlated with the occurrence of neonatal asphyxia. Serum homocysteine and folate levels are not associated with the gender. A more significantly increased serum homocysteine level may be found in asphyxiated neonates born at premature.

Evaluation of lactate dehydrogenase, creatine kinase and hepatic enzymes for the retrospective diagnosis of perinatal asphyxia among sick neonates

It is difficult to make a retrospective diagnosis of perinatal asphyxia in symptomatic neonates delivered non-institutionally. We studied serum creatine kinase muscle-brain fraction (CK-MB), lactate dehydrogenase (LDH), glutamic oxaloacetic transaminase (SGOT) and glutamic pyruvate transaminase (SGPT) for differentiating asphyxiated (n=25) from non-asphyxiated (n=20) neonates who present with non-specific signs of sickness. CK-MB was assayed at 8 and 24 h; and LDH, SGOT and SGPT at 72 h of life. On comparing cases and controls, median 8-hr CK-MB [80 U/L vs. 26 U/L respectively, P< 0.001], median 24-hr CK-MB [33.5 U/L vs. 21.5 U/L respectively, P=0.009] and median LDH [965 U/L vs. 168 U/L respectively, P< 0.001] were higher in asphyxiated neonates. Raised LDH had 100% sensitivity, while CK-MB had 100% specificity for asphyxia. LDH had the highest area under ROC curve (0.998). We conclude that LDH at 72 hr of life is most accurate at differentiating asphyxiated from non-asphyxiated symptomatic neonates.

[Birth asphyxia, neonatal risk factors for hypoxic ischemic encephalopathy]

OBJECTIVE

Neonates suffering from severe birth asphyxia may develop hypoxic ischemic encephalopathy (HIE), some of which develop permanent neurological damage. As the incidence of asphyxia and HIE in Iceland is unknown, this study was conducted. Furthermore, we evaluated the association between some neonatal risk factors and the development of HIE.

MATERIAL AND METHODS

All term infants born at LSH from 1997-2001 with birth asphyxia, defined as 5 minute Apgar score or=<6, were included in the study. Clinical information, length and weight, Apgar scores at 1, 5 and 10 minutes normoblasts count, initial pH and hemoglobin levels were retrospectively collected.

RESULTS

The incidence of HIE after birth asphyxia was 1.4/1000. The infants who developed HIE had significantly lower birth weight and Apgar scores at one, five and ten minutes. They also had lower umbilical artery pH, had more base deficit and lower serum bicarbonate concentrations than the infants who did not develop HIE.

CONCLUSION

The incidence of HIE was low compared to other studies. Birth asphyxia resulting in HIE is associated with lower birth weight, Apgar scores, pH and neonatal hemoglobin levels at birth. We conclude that neonates with low hemoglobin level are at increased risk for developing HIE and that low pH and Apgar scores may predict worse outcomes after birth asphyxia.