Changes in laboratory parameters indicating cell necrosis and organ dysfunction in asphyxiated neonates on moderate systemic hypothermia

AIM

Asphyxia is a major cause of morbidity and mortality in term infants. In addition to cerebral injury other organs are also distressed due to hypoxic-ischaemic insult. Systemic hypothermia has a beneficial effect on brain injury. We tested the impact of hypothermia on hypoxic damage of other internal organs.

METHODS

Asphyxiated term neonates (n = 21) were randomised to groups treated with hypothermia (n = 12) and normothermia (n = 9). Hypothermia (33-34 degrees C) was initiated within 6 h of life, and maintained for 72 h. We determined serum transaminase, lactate dehydrogenase, creatine kinase, uric acid, creatinine levels and diuresis during 6, 24, 48 and 72 postnatal hours.

RESULTS

Area under curve values of aspartate aminotransferase (ASAT), lactate dehydrogenase (LDH), uric acid and creatinine during the investigated period and alanine aminotransferase (ALAT) value at 72 h were lower in neonates on hypothermia than in those on normothermia. Renal failure and liver impairment affected less hypothermic than normothermic neonates (3/12 vs. 7/9, p = 0.03, 3/12 vs. 6/9 p = 0.08, respectively). Four of the 12 hypothermic and 6 of the 9 normothermic neonates developed multiorgan failure.

CONCLUSIONS

These results suggest that systemic hypothermia may protect against cell necrosis and tissue dysfunction of internal organs after neonatal asphyxia.

Elevated total peripheral leukocyte count may identify risk for neurological disability in asphyxiated term neonates

OBJECTIVE

The present study investigated the relationship between neurologic outcome and total circulating white blood cell (WBC) and absolute neutrophil counts (ANCs) in the first week of life in term infants with hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

Long-term neurologic outcome at 18 months was measured retrospectively in 30 term neonates with HIE using the Pediatric Cerebral Performance Category Scale (PCPCS) score with outcomes dichotomized as either good or poor. We then compared white blood cell and ANC levels during the first 4 days of life and magnetic resonance imaging (MRI) obtained within the first month life between the two PCPCS groups. MRI was quantified using a validated scoring system.

RESULTS

Neonates with good long-term outcomes had significantly lower MRI scores (indicating lesser injury) than neonates with poor outcomes. More importantly, neonates with poor outcomes had significantly higher WBC and ANC levels as early as12 h after birth and up to 96 h after birth compared to those with good outcomes. These data suggest that elevated peripheral neutrophil counts in the first 96 h of life may signal or predict adverse long-term outcome.

CONCLUSIONS

Our findings suggest that elevated peripheral neutrophil counts in the first 96 h of life in term infants with HIE may contribute to abnormal neurodevelopmental outcome.

Is serum troponin T a useful marker of myocardial damage in newborn infants with perinatal asphyxia?

AIM

To assess the correlation of echocardiographic signs of myocardial damage to serum cardiac troponin T (cTnT) concentrations in newborn infants with perinatal asphyxia.

METHODS

Electocardiograms (ECG) and echocardiograms (Echo) were obtained during the first 24 h of life from 29 asphyxiated and 30 control infants and correlated with cTnT concentrations. The echocardiographic parameters included systolic ventricular performance, preload, afterload, diastolic function, stroke volume (SV), left ventricular output (LVO), hyperechogenity of the papillary muscles and insufficiency of the atrioventricular valves.

RESULTS

LVO and SV were lower but CTnT were significantly higher in asphyxiated than in control infants: 0.15 (010-0.23) vs. 0.05 (0.02-0.13), p < 0.001). Asphyxiated infants with signs of myocardial damage were associated with significantly higher cTnT than those without, 0.20 (0.11-0.28) and 0.11 (0.05-0.14 ug/L), p = 0.04.

CONCLUSION

Cardiac troponin may prove to be valuable in evaluating myocardial damage in birth asphyxia. However, the degree of prematurity may complicate the assessment.

[Peculiarity of cell energy metabolism in newborns with hypoxic-ischemic encephalopathy caused by asphyxia]

The authors have studied changes of activity of succinate dehydrogenase (SD) of peripheral blood lymphocytes of newborn with hypoxic-ischemic encephalopathy at early neonatal period and against cerebrokurin medicine administration. Newborn children with hypoxic-ischemic encephalopathy due to severe asphyxia have significant disturbancies of cyto-energy metabolism which is proved through decrease in activity index of SD and decrease in quantity of the cells with moderate and high activity. Lymphocytes of newborns with severe asphyxia were caracterized on six days by absence of the cells with moderate and high activity. Newborns with severe asphyxia who had been prescribed cerebrokurin had on their six days considerable increase in lymphocytes with moderate and high activity.

Interleukin-8 and monocyte chemotactic protein-1 mRNA expression in perinatally infected and asphyxiated preterm neonates

BACKGROUND

Inflammation due to perinatal infection (PI) and perinatal asphyxia (PA) may cause damage to various tissues and very often to the immature brain of the fetus and the newborn. Previously, we have shown that the neonatal immune system has the ability to produce increased chemokine protein levels in the serum during the inflammatory response caused by PI and PA.

AIM

The aim of our present study was to investigate mRNA levels of the proinflammatory chemokines interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) in peripheral blood leukocytes from infected and asphyxiated neonates.

METHODS

Forty-two premature neonates were studied; 11 with PI, 16 with PA and 15 without PA and PI, were used as controls. IL-8 and MCP-1 mRNA levels were investigated in whole blood and in phytohemagglutinin-activated lymphocytes using semi-quantitative polymerase chain reaction and real-time polymerase chain reaction, respectively.

RESULTS

IL-8 mRNA levels were significantly increased in whole blood both during PA and PI, while MCP-1 mRNA levels were not. In vitro activated lymphocytes expressed significantly increased IL-8 mRNA levels during PI, whereas no increase was observed during PA. MCP-1 mRNA levels were significantly increased in activated lymphocytes during PA, while no increase was observed during PI.

CONCLUSIONS

Our data show that chemokine mRNA levels expressed by activated lymphocytes during inflammation caused by PIs are different to those expressed during PAs. These findings might have important implications during the administration of specific chemokine antagonists in order to prevent or reduce tissue damage caused by inflammation.

Effect of perinatal factors on cord blood thyroid stimulating hormone levels

OBJECTIVE

To study the influence of perinatal factors on cord blood (CB) TSH levels.

INFANTS AND METHODS

In a prospective cross-sectional study, CB TSH levels were measured in 1,590 live-born infants using IRMA. The effect of various perinatal factors on the CB TSH levels was analyzed statistically.

RESULTS

The mean TSH level in the study group was 10.6 +/- 6.7 microU/ml (range 0.01-66.4 microU/ml). A significant fall in CB TSH levels was noted with increasing gestational age. A similar decline was noted in TSH levels with increase in birth weight. No significant difference in TSH levels was noted between males and females, or AGA and SGA (n = 296) infants. Infants with birth asphyxia (Apgar score < 4 at 5 min) had significantly higher CB TSH levels (mean 31 microU/ml, n = 18) as compared to those without (mean 10.4 microU/ml) (p < 0.01). The highest TSH levels were noted in neonates delivered by forceps extraction (mean 29.4 microU/ml, n = 17) and lowest levels in infants born by elective Caesarian section (mean 8.7 microU/ml, n = 149).

CONCLUSION

CB TSH levels fall with increase in gestational age while birth asphyxia and difficult deliveries tend to elevate them.

Cord blood IGF-1 and IGFBP-3 levels in asphyxiated term newborns

OBJECTIVE

Determination and pathogenesis of perinatal asphyxia is still an important problem. During the asphyxial insult and recovery phase, alteration of the growth factors has been demonstrated and there is evidence that expression of insulin-like growth factors (IGF) and their insulin-like growth factor binding proteins (IGFBP) in injured sites in experimental studies. Aim of this study was to evaluate relationship between serum IGF-1, IGFBP-3 levels and perinatal asphyxia.

PATIENTS AND METHODS

18 term-newborn who defined as perinatal asphyxia and 12 term-healthy newborn were enrolled. Umbilical cord IGF-1 and IGFBP-3 levels were detected and searched correlation with apgar scores and umbilical artery gas analysis as pH, pC02, pO2, base excess, HCO3, ctO2, SO2 and lactate levels.

RESULTS

Cord blood IGF-1 and IGFBP-3 levels for asphyxiated newborns were lower than normal group (27.8+/-2.6 ng/ml, 55.1+/-2.8 ng/ml respectively, p<0.01 for IGF-1; 1107.7+/-320.4, 1682.5+/-364.1, p<0.001 for IGFBP-3). Cord blood IGF-1 levels were positively correlated with birth weight; first and 5th minute Apgar score, cord blood arterial pH, ABE, HCO3, SO2 levels. Cord blood IGFBP-3 levels were positively correlated with first and 5th minutes Apgar scores, cord blood arterial pH, pCO2, ABE, HCO3, sO2, and also negatively correlated with cord CO2 and cord lactate levels.

CONCLUSION

Our study demonstrates that exposure to hypoxia and acidosis at birth strongly correlated with a fall in IGF-1 and IGFBP-3 levels in cord blood.

Delivery as a "physiological stress" and its influence on some parameters of oxidative stress

OBJECTIVES

In healthy term newborns (HTN) to determine on the 1st and 5th day of life the activity of total antioxidant capacity (TAS), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPX) and to compare the values with the group of asphyxiated term newborns (ATN).

PATIENTS/METHODS

The series consisted of 15 HTN and 24 ATN. In both groups TAS, MDA, GPX and SOD were investigated.

RESULTS

Reference values in HTN (1st/5th day of life) for TAS were 0.52+/-0.03/0.49+/-0.04 mmol/l, for MDA 0.72+/-0.07/1.08+/-0.09 micromol/l, for SOD 594.20+/-16.47/591.23+/-14.14 Ug/Hb and for GPX 25.48+/-1.32/25.98+/-1.20 Ug/Hb. In a group of ATN the obtained values were (1st/5th day of life): TAS 1.1+/-0.08/0.98+/-0.08 mmol/l, MDA 2.08+/-0.22/2.21+/-0.34 micromol/l, SOD 509.18+/-26.8/564.49+/-36.4 Ug/Hb and GPX 30.2+/-1.9/32.45+/-2.69 Ug/Hb.

CONCLUSIONS

Statistically significant differences were found on the 1st and 5th day of life between the two groups investigated in values of MDA (**p<0.01) and TAS (**p<0.01). Increased values of MDA in the group of ATN on the 1st and 5th day of life confirmed the presence of lipoperoxidation. The obtained values of TAS on the 1st and 5th day of life in the group of ATN were surprisingly higher than in HTN. The increase of TAS in ATN could point to a certain ability of ATN to prevent the damage of balance between overproduction of MDA and antioxidants. The results of SOD and GPX activity were not statistically significant, yet they are indicative of the biochemical reaction of the organism of term newborns to asphyxia.

Dynamics of hepatic enzyme activity following birth asphyxia

AIM

To investigate: 1) the occurrence of hypoxic hepatitis in full-term infants after birth asphyxia, 2) the temporal enzyme pattern in asphyxiated newborn infants, and 3) whether the degree of hypoxic hepatitis, as reflected by the rise in aminotransferase, correlates with the severity of the asphyxia and CNS symptomatology.

METHODS

Serum aminotransferases, lactate dehydrogenase, gamma-glutamyl transferase, total and conjugated bilirubin, cholinesterase activity, albumin, international normalized ratio (INR), and nucleated red blood cell count were prospectively measured in full-term asphyxiated newborn infants (n=26). Samples were collected three times during the first 72 h and once between days 6 and 12 after birth. Samples from healthy newborns (n=56), collected 24-172 h after birth, served as controls.

RESULTS

In 12 of the 26 asphyxiated infants, a serum alanine aminotransferase (S-ALAT) pattern compatible with hypoxic hepatitis was found. Five infants showed increased S-ALAT activity but with a different pattern. Similar patterns were seen in serum aspartate aminotransferase (S-ASAT). S-ALAT and -ASAT concentrations 0-72 h after birth correlated significantly with severity of hypoxic-ischaemic encephalopathy.

CONCLUSION

Birth asphyxia can induce an enzyme pattern in serum compatible to hypoxic hepatitis. There seems to be a correlation between aminotransferases in serum and the extent of CNS injury.

Retrospective diagnosis of hypoxic myocardial injury in premature newborns

Perinatal asphyxia has a high impact on neonatal mortality, morbidity, and neurological outcome. The hypoxic effects on brain, kidney and gastrointestinal system are well recognized in newborns. While it is known that hypoxia also effects cardiac function, there are few studies of quantitative myocardial injury in premature infants who suffered hypoxia.

AIM

To investigate usefulness of cardiac troponin (cTnT) and creatinine kinase MB (CK-MB) in the diagnosis of myocardial injury due to birth hypoxia and to correlate these markers with cardiac functions as measured by echocardiogram.

METHODS

We studied 43 preterm infants: 21 with birth asphyxia and 22 controls. Echocardiographic studies and quantitative determination of cTnT and CK-MB in blood serum was performed between the 12(th) and the 24(th) h of life.

RESULTS

cTnT and CK-MB levels were higher in asphyxiated infants compared to controls (0.287 +/- 0.190 vs. 0.112 +/- 0.099 ng/mL, P < 0.001) and (18.35 +/-14.81 vs. 11.09 +/- 5.17 ng/L, P < 0.05). Among controls, we observed an elevated value of cTnT in those with respiratory distress syndrome (RDS). We found a decrease in fractional shortening (P < 0.05) and an increase in tricuspid insufficiency (P < 0.01) in asphyxiated newborns.

CONCLUSIONS

cTnT and CK-MB levels are strong indicators of myocardial injury due to perinatal hypoxia. The cTnT level was most strongly related to RDS.

Platelet dysfunction in asphyxiated newborn piglets resuscitated with 21% and 100% oxygen

Hemostatic disturbances are common in asphyxiated newborns after resuscitation. We compared platelet function in hypoxic newborn piglets reoxygenated with 21% or 100% oxygen. Piglets (1-3 d, 1.5-2.1 kg) were anesthetized and acutely instrumented for hemodynamic monitoring. After stabilization, normocapnic hypoxia was induced with an inspired oxygen concentration of 10-15% for 2 h. Piglets were then resuscitated for 1 h with 21% or 100% oxygen, followed by 3 h with 21% oxygen. Platelet counts and collagen (2, 5, and 10 microg/mL)-stimulated whole blood aggregation were studied before hypoxia and at 4 h of post-hypoxia/reoxygenation. Platelet function was studied using transmission electron microscopy and by measuring plasma thromboxane B2 (TxB2) and matrix metalloproteinase (MMP)-2 and -9 levels. Control piglets were sham-operated without hypoxia/reoxygenation. The hypoxemic (PaO2 33 mm Hg) piglets developed hypotension with metabolic acidosis (pH 7.02-7.05). Upon reoxygenation, piglets recovered and blood gases gradually normalized. At 4 h reoxygenation, platelet aggregation ex vivo was impaired as evidenced by a rightward-downward shifting of the concentration-response curves. Electron microscopy showed features of platelet activation. Plasma MMP-9 but not MMP-2 activity significantly increased. Resuscitation with 100% but not 21% oxygen increased plasma TxB2 levels. Platelet counts decreased after hypoxia/reoxygenation but were not different between groups during the experiment. Resuscitation of hypoxic newborn piglets caused platelet activation with significant deterioration of platelet aggregation ex vivo and increased plasma MMP-9 levels. High oxygen concentrations may aggravate the activation of prostaglandin-thromboxane mechanistic pathway.

[The role of S100B-protein in neonatology, pediatric intensive care, and pediatrics]

During the last years neuromonitoring with various biochemical markers such as S100B protein has been introduced into the clinical settings of neonatal and pediatric intensive care. Several investigations have been undertaken to correlate S100B protein concentrations to the diagnosis and prognosis of neonates and children with severe cerebral disorders. This articles gives a review on the current knowledge, indications and limitations on the use of S100B protein after non-traumatic and traumatic brain injury in neonates and children.

Elevation of Cytokine Concentrations in Asphyxiated Neonates

BACKGROUND

Various cytokines are reportedly associated with many neonatal diseases. Asphyxia is considered to result in ischemia-reperfusion injuries and induces abnormal inflammatory responses involving excessive cytokine production.

OBJECTIVES

To evaluate alteration in sera levels of various cytokines/chemokines in case of perinatal asphyxia at birth.

METHODS

In order to determine the concentrations of various cytokines/chemokines in sera, we used a highly sensitive fluorescence microsphere method. We measured the concentration of 8 types of cytokines/chemokines in sera obtained from 17 cases of asphyxia, 10 normal neonates, and 6 healthy adults.

RESULTS

The concentrations of IL-6, IL-8, and IL-10 in the sera of asphyxiated neonates were higher than those in the normal neonates. Irrespective of the presence or absence of asphyxia, sera concentrations of IL-2, IL-4, IFN-gamma, and TNF-alpha were higher in the neonates than those in the adults. The concentration of IFN-gamma in the asphyxiated neonates was lower than that in the normal neonates. Sera levels of IL-10 were higher in the asphyxiated cases than those in the normal neonates. The sera levels of IL-6, IL-8, and IL-10 in asphyxiated neonates with either a poor outcome or death were higher than those without poor outcomes.

CONCLUSIONS

The concentrations of various types of cytokines/chemokines were different in neonatal sera and some of them increased drastically during asphyxia. The concentration of an anti-inflammatory cytokine IL-10 was elevated in asphyxiated neonates immediately after birth, thereby suggesting that IL-10 might be associated with neuroprotective functions.

S100B protein related neonatal hypoxia

Biochemical markers have played an increasingly relevant role in the assessment of neonatal asphyxia. The S100B protein is particularly important in research conducted in this field. The purpose of this study was to underline the importance of the S100B protein in the assessment of term newborn infants with hypoxic-ischemic encephalopathy, as well as to relate it to other substances also involved in the ischemic process. An assessment was made from September 2003 to October 2004 of 21 term newborn infants who developed hypoxic-ischemic encephalopathy. Samples were collected on the 1st and 4th day of life and S100B protein and lactate concentrations were calculated using the immune cytochemical method. A positive relationship was found between the two substances. Additionally, a comparison between the two substances showed a statistically significant correlation.

Magnesium therapy in birth asphyxia

OBJECTIVE

Glutamate plays a critical role in the hypoxic ischaemic neuronal death. Two mechanisms of glutamate- induced neuronal death have been identified. One is rapid cell death that occurs in minutes and the second is delayed cell death that occurs over hours and is initiated principally by the activation of the N-methyl D-Aspactate (NMDA) receptor. Magnesium (Mg) is an NMDA receptor blocker. Systemic administration of Mg after a simulated hypoxic ischaemic insult has been shown to limit neuronal injury in several animal models. However, before embarking on to the use of Mg for neuronal protection in the human neonate it is important to study the safety and side effects of Mg administration.

METHODS

Forty terms, appropriate for gestational age babies with severe birth asphyxia (1 min Apgar score < 3 and 5 min Apgar score < 6), were randomly assigned to either the study group or the control group. Infants in both groups were treated as per unit protocol except that babies in the study group received intravenous injection of magnesium sulphate 250 mg/kg within half an hour of birth and subsequently 125 mg/kg at 24 and 48 hours of life.

RESULTS

The mean cord blood serum Mg levels were 0.78 (+/- 0.047) mmol/L in the control group and 0.779(+/-0.045) mmol/L in the study group. The serum Mg levels at 3, 6, 12, 24, 48 and 72 hours of life were 1.87(+/-0.6), 1.65(+/-0.059), 1.468 (+/-0.91), 1.881 (+/- 0.053), 1.916 (+/- 0.053) and 1.493 (+/- 0.084) mmol/L respectively in the study group. All these values were significantly higher than those obtained in the control group (p< 0.001). No significant alterations in heart rate, respiratory rate, oxygen saturation and mean arterial pressure were seen, following magnesium infusion with either 250 mg/kg or 125 mg/kg dose. The serum Mg levels in the study group ranged between 1.493 (+/- 0.084) and 1.916(+/-0.053) mmol/L, which are considered to be in the neuroprotective range.

CONCLUSION

Injection MgSO4 administered in a dose of 250 mg/kg and 125 mg/kg as an intravenous infusion is safe and the Mg levels obtained are in the range considered to be neuroprotective.

[Clinical study on improving the diagnostic criteria for neonatal asphyxia]

OBJECTIVE

Diagnosing neonatal asphyxia solely according to Apgar score may lead to misdiagnosis. The aim of this study was to explore new and more accurate diagnostic criteria for neonatal asphyxia.

METHODS

Totally 10 376 live born neonates in our hospital were consecutively enrolled into the study. The following five items related to birth asphyxia, i.e., antepartum high-risk factors, Apgar scores, umbilical artery blood pH, organ injury, differential diagnosis on the causes of low Apgar score cases were examined and registered. The relationship among the first 4 items were analyzed. By differential diagnosis, the sensitivity and specificity of each index on diagnosing asphyxia and their complementary value on each other were investigated.

RESULTS

The items correlated well with each other (P < 0.01 or < 0.05) but were not entirely parallel and consistent; they could complement but could not substitute for each other. The sensitivity of antepartum high-risk factors, low Apgar scores, umbilical artery blood pH < 7.00 and organ injury was 100%, 100%, 44.44% and 100%, while the specificity was 17.99%, 98.90%, 96.05% and 96.62%, respectively. Of the 230 low Apgar score cases in this series only 50.9% coincided with asphyxia. For the 230 cases, when low Apgar score was combined with umbilical artery blood pH < 7.00, the sensitivity and specificity were 41% and 99.1% and when low Apgar score was combined with umbilical artery blood pH < 7.20, the sensitivity and specificity were 100% and 29.20%, respectively. After organ injury was added, the specificity was increased to 65.49%. When differential diagnosis was further added to exclude the other causes of low Apgar score cases, the misdiagnosis rate was minimized.

CONCLUSION

Up to now, no single accurate index for diagnosing neonatal asphyxia is available. In order to increase diagnostic bases and reduce misdiagnosis, the criteria of sole Apgar score should be replaced by multi-index diagnostic criteria. Based on the present study, a set of integrated diagnostic criteria for neonatal asphyxia is proposed: (1) prenatal high-risk factors, (2) low Apgar scores (respiratory depression must present), (3) umbilical artery blood pH < 7.00, if only pH < 7.20, the items (2) (4) (5) must be present, (4) hypoxic-ischemic organ injury (at least one organ dysfunction), (5) the other causes of low Apgar scores should be excluded. The last 4 indexes should all be met and the first one serves as reference. If multi-organ (three or more organs) dysfunction and (or) hypoxic-ischemic encephalopathy are present, severe asphyxia can be diagnosed.

Screening of foetal distress by assessment of umbilical cord lactate

PURPOSE OF INVESTIGATION

Studies on umbilical cord blood for determination of lactate indicate that high levels seem to be correlated to foetal metabolism for anaerobic glycolysis taking place in oxygen-deprived tissues of the foetus. These findings may be of particular-deprived clinical importance when foetal distress or foetal hypoxemia is caused by perinatal events.

METHODS

The maternal and foetal heart rates, acid-base values measured and the outcome of 94 pregnancies complicated by intrapartum foetal asphyxia have been reviewed, and the maternal and foetal acid-base and lactate levels during the course of labour and at delivery were studied in patients with evidence of metabolic acidosis. Lactate concentrations were measured during labour and at delivery in blood samples obtained from the foetal presenting part and from the umbilical cord with the use of a rapid electrochemical technique. The foetuses were evaluated by means of the Apgar score, intrapartum cardiotocography, observation of the presence of meconium stained amniotic fluid, and clinical features of distress at birth.

RESULTS

Evidence of clinical foetal distress was not related to the severity of the asphyxia. An increased lactate level was found in asphyctic infants and a clear correlation between lactic acidosis and foetal distress was documented. Low Apgar scores were observed in infants with moderate or severe asphyxia at delivery. Scalp lactate correlated significantly with umbilical artery lactate, but not with 1-min or 5-min Apgar scores. The lactate concentration was higher in cases of instrumental delivery compared to spontaneous delivery. No perfect correlation was found between lactate level and neonatal outcome but there were not a significant number of neonates with immediate complications. The rate of forceps delivery in the distress group was significantly higher than that of the healthy foetuses, so spontaneous labour was less frequently associated with foetal distress than instrumental delivery. In the distress group, severe variable decelerations were generally recorded in the second stage of labour. The incidence of neonatal Apgar score < or = 7 in neonates with abnormal baseline foetal heart rate (FHR) was higher than in those with severe variable decelerations, mild variable decelerations, and transient tachycardia. Duration of the active second stage of labour was significantly with the presence of foetal lactate at the time of crowning of the foetal head and the presence of lactate in umbilical arterial and vein blood at delivery. Expulsion time > or = 45 minutes, compared with shorter active second stage, and acidaemia at birth implied larger arterial-venous lactate differences. The presence of foetal lactate at crowning was also significantly associated with the level of umbilical arterial-venous lactate difference.

CONCLUSION

Lactate and pH values provide the best parameters to distinguish between asphyctic and normal newborns, with lactate having the most discriminating power. The prospective value of the discrimination functions derived from lactate and pH data is good when the foetuses are allocated into normal parameters but poor when an attempt is made to allocate the foetuses into pathologic ones, with a high false-negative rate. However, the discriminating ability is improved when pathologic foetuses are included into one single abnormal group. These results confirm the potential use of rapid foetal blood lactate measurements for the early diagnosis of intrapartum foetal distress.

Cardiac troponin I in asphyxiated neonates

BACKGROUND

Cardiac troponins T (cTnT) and I (cTnI) are well-established markers in detecting myocardial ischemic damage in adults. Perinatal asphyxia is associated with cardiac dysfunction.

OBJECTIVES

To evaluate serum concentrations of cTnI in asphyxiated neonates and to investigate whether cTnI is correlated with the traditional markers of asphyxia.

METHODS

Blood samples were collected from 13 asphyxiated neonates (umbilical artery pH<7.18 and either a 1-min Apgar score<4 or a 5-min Apgar score<7) and 39 controls. Data on gestation, birth weight, sex, Apgar scores, mode of delivery, umbilical pH, creatinine, serum activity of aspartate and alanine aminotransferase, and QTc interval were investigated.

RESULTS

Median (range) cTnI concentrations were significantly higher in asphyxiated neonates with respect to healthy infants: 0.36 microg/l (0.05-11) versus 0.04 microg/l (0.04-0.06); p<0.01. In asphyxiated babies, no statistically significant correlations were found between concentrations of cTnI and the other markers of asphyxia.

CONCLUSIONS

In asphyxiated neonates, cTnI concentrations are higher with respect to healthy infants, suggesting the presence of myocardial damage in this group of high-risk patients. cTnI does not correlate with the traditional markers of asphyxia.

Umbilical cord unbound free fatty acid concentration and low apgar score

Increased levels of unbound Free Fatty acid (FFAu) have been found in adults undergoing coronary angioplasty as a result of acute hypoxia-ischemia. We hypohesized that infants suffering from a 1-minute Apgar score of less than 5 will demonstrate elevated FFAu levels in the cord blood. One hundred ninety-nine infants between 25 and 41 weeks gestational age were enrolled in the study. Infants with an Apgar score of less than 5 at 1 minute served as the study group. Blood samples were collected from the umbilical cord and serum FFAu levels were measured with the fluorescent probe acrylodan-derivatized intestinal fatty acid binding protein. The low Apgar score group (n=32, birthweight 3153+/-780 g, gestational age 37.9+/-3.1 weeks) and normal Apgar score group (n=167, birthweight 3067+/-847 g, gestational age 37.5+/-3.5 weeks) were significantly different with respect to Apgar score at 1 minute (3.0+/-1.2 versus 8.4+/-1.1), Apgar score at 5 minutes (6.9+/-versus 8.9+/-0.5), cord pH (7.16+/-0.12 versus 7.28+/-0.07), and in the frequency of meconium passage (40.6% versus 14.9%). Cord FFAu levels were 4.4+/-1.7 versus 3.2+/-1.2 nM (p<0.001), respectively. Cord FFAu correlated inversely with Apgar score at 1 minute (r=-0.31, p<0.05) and with cord pH (r=-0.12, p<0.05), but not with birthweight or gestational age. In infants with low 1-minute Apgar scores, cord free fatty acid levels were significantly elevated compared with those from controls.

Troponin-T levels in perinatally asphyxiated infants during the first 15 days of life

AIM

To measure serial cardiac troponin-T, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase levels in asphyxiated newborn infants during the first 15 d of life.

METHODS

Troponin-T, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase (LDH) concentrations were measured prospectively in blood samples obtained from 45 asphyxiated and 15 healthy term neonates within the first 2-4 h, third, seventh and 15th days.

RESULTS

Infants with severe asphyxia had significantly higher cardiac troponin-T levels than grade I and II asphyxiated and healthy neonates within the first 2-4 h of life (0.34+/-0.21 ag/ml vs 0.07+/-0.03 ag/ml, 0.12+/-0.07 ag/ml, 0.04+/-0.02 ag/ml, respectively). Troponin-T levels remained high on days 3 and 7 in severely asphyxiated neonates. The creatinine kinase-MB levels were significantly higher in grade II and III asphyxiated neonates than grade I asphyxiated and healthy neonates within the first 2-4 h. No difference was found in creatinine kinase-MB on day 3. There was cardiac involvement in 12 (80%) newborns of group III on B mode echocardiographic images on day 1. However, no echocardigraphic pathology was found in the seventh- and 15th-day echocardiographic analysis in any groups.

CONCLUSION

Our results suggest that asphyxia-related cardiac changes were significant but reversible in severely asphyxiated neonates, and troponin T is a good determinant of the degree of injury to the heart within the first week of life. Cardiac troponin T also has a wider diagnostic frame than other diagnostic markers of myocardial damage.

Room-air resuscitation causes less damage to heart and kidney than 100% oxygen

RATIONALE

Pure oxygen causes more oxidative stress than room air in resuscitation of asphyctic neonates, and consequently could be associated with increased tissue damage.

OBJECTIVES

To compare damage caused to heart and kidneys on reoxygenation in severely asphyctic term neonates resuscitated with room air (RAR) or 100% oxygen (OxR). Nonasphyctic term newborn infants served as a control group.

METHODS AND MEASUREMENTS

This is a prospective randomized clinical trial masked for the gas mixture. Reduced glutathione (GSH), oxidized glutathione (GSSG), and superoxide dismutase (SOD) activity were measured to assess oxidative stress. Plasma cardiac troponin T (cTnT) and urinary N-acetyl-glucosaminidase (NAG) assessed cardiac and renal damage, respectively. Daily determinations of NAG for a 2-wk period were performed to monitor postasphyctic renal damage.

MAIN RESULTS

Both asphyctic groups showed oxidative stress when compared with the control group as evidenced by diminished GSH/GSSG ratios, adaptive increases in SOD activity, and higher values of NAG and cTnT (markers of tissue damage). However, the OxR group showed significantly higher values of NAG and cTnT, lower GSH/GSSG ratios, and higher SOD activity than the RAR group. Moreover, NAG values persisted in being higher than normal in the OxR group for 2 wk after birth, whereas NAG in the RAR group dropped to normal within the first week. A linear correlation between cTnT or NAG and GSSG was found.

CONCLUSIONS

The use of room air on resuscitation causes less oxidative stress and damage to heart and kidney than pure oxygen.

Comparison of serum cardiac troponin T and creatine kinase MB isoenzyme mass concentrations in asphyxiated term infants during the first 48 h of life

OBJECTIVE

This prospective study aimed to compare serum creatine kinase MB isoenzyme (CK-MB) mass concentrations and cardiac troponin T (cTnT) concentrations during the first 48 h of life in asphyxiated term infants.

METHODS

Serum cTnT and CK-MB mass concentrations of 50 term infants with clinical features of perinatal asphyxia were measured at birth and at 12, 24 and 48 h of age by chemiluminescence immunoassay. These infants were followed up until discharge or death. Cord blood CK-MB and cTnT concentrations of 50 healthy term infants were also assayed.

RESULTS

At birth, asphyxiated infants had significantly higher concentrations of cTnT and CK-MB than controls (P < 0.0001). Serum cTnT of asphyxiated infants with low ejection fraction <60% was significantly higher at 12 and 24 h than those with normal ejection fraction (P < 0.05). Asphyxiated infants with congestive cardiac failure had significantly higher serum cTnT concentration during the first 48 h of life than those without congestive cardiac failure (P <or= 0.04). Serum cTnT concentrations during the first 48 h of life were significantly higher in asphyxiated infants who died than those who survived (P < 0.0001). There was no significant difference in serum CK-MB mass concentrations between asphyxiated infants with and without these complications (P >or= 0.1).

CONCLUSION

Unlike CK-MB, serum cTnT concentrations are significantly higher in asphyxiated infants who die or develop cardiac dysfunction.