Complement fragment C3a in plasma of asphyxiated neonates

Recent clinical studies with adult polytrauma patients indicate that elevated plasma levels of anaphylatoxin C3a correlate with the subsequent development of the adult respiratory distress syndrome (ARDS). However, there are no parameters which allow a reliable diagnosis of ARDS in neonates. As the most predisposing condition for ARDS seems to be shock, plasma C3a was determined in 30 ventilated premature infants and neonates with respiratory distress syndrome (birth weights 660-3350 g) within the first 24 h post partum or 6-24 h after acute asphyxia or shock during the neonatal period. The range of C3a, measured by ELISA, was between 57 and 1000 ng/ml. In the asphyxia group (n = 15) peak levels of C3a in plasma (mean 388 ng/ml) were significantly higher (P less than 0.001) than in the control group (mean 153 ng/ml). In some neonates with suspected ARDS, additional samples were taken. A rise in C3a between days 2 and 8 was associated with a fatal outcome of the disease. As in adults, C3a might be a useful indicator for ARDS in neonates.

[A new procedure for continuous measurement of fetal oxygen saturation sub partu]

The principal aim of foetal monitoring during labor is early detection of hypoxia. Current methods are unable to accomplish this task. Pulse oximetry permits continuous measurement of oxygen saturation and is the best method to detect early hypoxia. In this report, an optical scalp electrode is presented, which permits continuous monitoring of foetal oxygen saturation during labor.

Reliability of capillary blood gas estimation in neonates

In order to compare the reliability of capillary blood gases to the arterial blood gases, we studied fifty one neonates with moderate birth asphyxia. A significant difference (p less than 0.05) was found between the capillary and the arterial blood gas values with respect to blood pH, PCO2 PO2 and oxygen saturation. However, the levels of blood bicarbonate as assessed by the 2 samples were comparable. Capillary blood gas values are unsatisfactory indicators of the arterial blood gas values and may result in inappropriate management.

The effect of preterm birth on umbilical cord blood gases

Apgar scores are used routinely to assess early neonatal status, but are less accurate in the preterm neonate because of developmental immaturity. Attention has been directed to umbilical cord gases as a method of neonatal evaluation. Using a retrospective chart review of all viable preterm births (24-36 weeks' gestation) between January 1986 and December 1989, we tabulated the umbilical cord gas indices of these infants. Fetuses with lethal congenital anomalies and those with abnormal heart rate tracings on admission were excluded from the data base, leaving 1872 infants. Cord arterial blood gas values were available for analysis in 74.4% of cases and cord venous gas values in 81.8%. The mean (+/- standard deviation [SD]) arterial and venous umbilical cord blood gas values for the preterm infants, were, respectively: pH, 7.26 +/- 0.08 and 7.33 +/- 0.07; oxygen pressure, 19.0 +/- 7.9 and 29.2 +/- 9.7 mmHg; carbon dioxide pressure, 53.0 +/- 10.0 and 43.4 +/- 8.3 mmHg; bicarbonate, 24.0 +/- 2.3 and 22.8 +/- 2.1 mEq/L; and base excess, -3.2 +/- 2.9 and -2.6 +/- 2.5 mEq/L. Acidemia was defined statistically as 2 SDs or more below the population mean. The incidence of 5-minute Apgar scores below 7 in the preterm infants was 8.5% and within this group, 17.8% were acidemic (arterial pH 7.10 or lower). More than 82% of neonates with 5-minute Apgar scores less than 7 had normal umbilical cord blood gases. There was no significant difference in umbilical arterial blood gas values between preterm infants and 1924 term deliveries at our institution between 1986-1988.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of cord purine metabolites to maternal and neonatal variables of hypoxia

Umbilical arterial concentrations of purine metabolites were evaluated prospectively as markers of hypoxia. The results suggest that hypoxanthine accumulates in association with fetal acidosis and reduced levels of buffer base (P less than .01). Acute hypoxemia defined by umbilical arterial oxygen pressure was accompanied by elevation of uric acid concentrations (P less than .01). Fetal heart rate tracings with characteristics classically associated with fetal stress correlated with increased concentrations of hypoxanthine and xanthine (P less than .01). Therefore, intrapartum events may occur that are not documented by standard markers of perinatal hypoxia at delivery.

[The results of the therapeutic monitoring of piracetam in parturients and newborn infants]

Overall 30 women in childbirth with preeclampsia and fetoplacental dysfunction received piracetam solution which was given initially in a dose of 5 g by intravenous drip, rapidly since the onset of labour and then every 2 hours till the end of labour in a dose of 2 g by jet injection. This made it possible to increase fetus resistance to hypoxic conditions. The concentrations of piracetam within the range of 60-80 g/l in the blood of women in childbirth should be viewed as minimum therapeutic. A single daily intramuscular injection of piracetam (50 mg/kg) into neonates with encephalopathies may build up blood concentrations equal to 25-60 mg/l after 2 hours. The drug is not detectable in the blood by the moment the next injection is given.

[Plasma cortisol levels in the newborn infants with hypoxic and traumatic injuries of the spinal cord]

Adrenal glucocorticoid function was studied in 56 newborns with natal injuries of the cervical section of the spine and the contribution of the hypoxic factor to such injuries defined. The babies were examined by the cliniconeurologic and electron-neuromyographic methods in order to specify the level of the injury. Blood serum and umbilical blood hydrocortisone levels were radioimmunoassayed immediately at birth and on days 5-7 of life. Spinal injury at the C1-C4 level was associated with low hydrocortisone levels, that may be regarded as an additional criterion for the differentiation of the level of injury in traumas of the cervical portion of the spine in the newborns.

Prediction of survival in severely asphyxiated infants

There is currently no set of evaluations that allows for the accurate prediction of survival or death following severe perinatal asphyxia and the development of hypoxic-ischemic encephalopathy. We hypothesized that low cerebral blood flow velocity, as determined by Doppler ultrasonography, may predict neurologic nonviability in a group of severely asphyxiated infants who exhibited signs of severe encephalopathy. Using the staging system of Sarnat and Sarnat, 11 infants who had had severe perinatal asphyxia were studied at the time that their neurologic examinations met the criteria for stage 3 encephalopathy. Apgar scores, cord or initial blood gases and pH, blood pressure, heart rate, and electroencephalographic findings were similar between those infants who survived (N = 8) and those who died due to cerebral injury (N = 3). Cerebral blood flow velocity, however, was significantly lower in those infants who died (3,288 +/- 884 vs 1,051 +/- 789 planimeter units/min; P less than .005). All infants who died had retrograde diastolic blood flow in the common carotid artery. In the study group the combination of low cerebral blood flow velocity and retrograde diastolic blood flow in the common carotid artery allowed prediction of survival and death with sensitivity and specificity of 100% (P less than .006). Following perinatal asphyxia and the development of severe encephalopathy, the finding of low cerebral blood flow velocity appears to be predictive of neurologic nonviability.

[Serum potassium level in healthy neonates and infants with asphyxia in the first 144 hours of life]

Postpartal increase in the plasma potassium concentration of asphyxiated newborn infants is a very rare complication with possibly deleterious outcome. In a group of 98 asphyxiated and 87 healthy infants we have not seen either a case of severe hyperkalemia or rhythm disturbances. We found lower reference-ranges for plasma potassium concentration in the group of healthy infants than previously published, which we would like to introduce. The pathogenesis of hyperkalemia in hypoxia is not yet fully understood. Further experimental investigations will be necessary.

Plasma immunoreactive endothelin-1 concentration in human fetal blood: its relation to asphyxia

To elucidate the effects of birth stress on immunoreactive endothelin-1 (irET-1) concentrations in fetal blood, we determined irET-1 levels in cord plasma in different modes of delivery associated with or without complications such as asphyxia. The irET-1 concentrations in both the umbilical artery and vein were significantly higher than those found in maternal venous blood at delivery, although there was no significant difference between preterm and full-term infants. When plasma irET-1 concentrations of healthy infants born by vaginal delivery and by cesarean section without labor were compared, the former had significantly (p less than 0.05) higher levels than the latter (15.4 +/- 4.9 pg/mL versus 11.1 +/- 3.1 pg/mL). Furthermore, umbilical venous plasma obtained from vaginally delivered infants complicated by asphyxia showed significantly (p less than 0.001) higher irET-1 levels (28.2 +/- 9.4 pg/mL) than those of nonasphyxiated infants (14.2 +/- 4.5 pg/m). These data suggest that birth stress, especially asphyxia, may contribute to the increase in fetal circulating irET-1 levels.

Variation of initial serum bilirubin rise in newborn infants with type of illness

Hyperbilirubinaemia in newborn infants is generally regarded as a problem, and bilirubin itself as toxic metabolic waste, but the high frequency in newborn infants suggests that the excess of neonatal bilirubin may have a positive function. To investigate the hypothesis that bilirubin has a role as a free-radical scavenger, the rate of rise in serum bilirubin in the first few days of life was measured in 44 infants with five illnesses thought to enhance free-radical production and in 58 control infants. The infants were selected from 2700 consecutive births by exclusion of those with factors known to affect bilirubin metabolism, including enteral feeding. The control infants were those who seemed to be ill and received treatment, including restriction of enteral feeds, but in whom no illness, or disorders not related to free-radical production, were found. The mean serum bilirubin rise was significantly lower in the combined illness group than in the control group (36.1 [95% Cl 26.9-45.3] vs 66.7 [55.9-77.5] mumol.l-1.day-1; p less than 0.0001). In subgroup analyses the mean rises in infants with circulatory failure, neonatal depression/asphyxia, aspiration syndromes, and proven sepsis were significantly lower than in controls matched for gestational age and birthweight, but rises in infants with respiratory distress and their matched controls did not differ. These findings are consistent with the hypothesis that bilirubin is consumed in vivo as an antioxidant. Such consumption may operate in vivo in addition to the standard pathways for bilirubin metabolism (production, isomerisation, and excretion).

[Polycythemia in the newborn. III: blood volume in asphyxia and meconium]

Several authors had reported high blood volumes (BV) and Low placental residual blood volumes (PRBV) in hypoxic human newborns, and also in asphyxiated experimentally animals. Those findings could be explained by and exaggerated intrauterine placental transfusion, ante or intrapartum. The authors had observed high cord blood and 24-48 hs. hematocrits in meconium-stained amniotic fluid (MSAF) and/or low 1 minute Apgar score newborns (Nb), despite early cord clamping. Sometimes, by delaying cord clamping up to 1 minute, those hematocrits had a tendency to decrease, instead of increasing. In view of that, it was decided to measure BV in a small group of similar type of Nb's with Evans blue (T-1824) and to practice in some of them a delayed cord clamping, but elevating the infant above the introitus (DECC). The BV values obtained were a little higher than the ones from the literature, being the most elevated in Nb's with MSAF and the lowest from cesarean. Also, the early cord clamping babies had higher BV than the DECC. All the MSAF Nb's had low plasmatic BV. BV was positively related to Birth Weight and the Hematocrit, and inversely to the Apgar score and the cord blood pH. Unexpectedly, delayed cord clamping was only slightly related to Red Cell BV, not to BV. MSAF constitutes 10% of all deliveries and delayed cord clamping has to be re-evaluated, because it offers a good chance for those babies of developing a normal BV or Hct's.

[Importance of monitoring theophylline and caffeine plasma levels in the management of neonatal apnea]

The simultaneous determination of caffeine and theophylline plasmatic levels has been proposed when the later is used in the treatment of the newborn's apnea. The caffeine plasmatic levels have been measured in five premature newborns treated with theophylline and the percentage of caffeine respect of theophylline, appraising its possible clinic repercusion. All the patients obtained theophylline levels into the therapeutic range proposed and a good efficacy was obtained without toxicity data, but there were a great interindividual variation in the amount of caffeine derived from theophylline (range from 12 to 50%). This result suggests the convenience of monitoring both drugs, especially when toxicity appear with theophylline levels into the therapeutic range.

[Structural and functional aspects of erythrocyte membrane in children, delivered with asphyxia]

Serum and red blood cell membrane lipid peroxidation (LPO), antioxidative activity (AOA) of the ceruloplasmin/transferrin (CP/TF) system, and biophysical parameters of the structure of a red blood cell membrane lipid bilayer were examined in fetuses experienced acute hypoxia at birth and in babies born to healthy mothers with uncomplicated pregnancy. The intensity of LPO product accumulation in mild asphyxia was ascertained to be proportional to the duration of hypoxic exposure of a fetus. In severe asphyxia accompanied by lower formation of primary LPO products, the levels of secondary LPO products showed a rise. A slight increase of AOA in the CP/TF system was unable to adequately compensate a high intensity of LPO processes, which provides strong evidence for altered structural parameters in the lipid bilayer. It was concluded that it was essential to correct hypoxic states in children with antioxidants immediately after birth.

Sonography-guided fetal blood sampling for pH and blood gases in premature fetuses with abnormal fetal heart rate traces

In nine pregnancies, remote from term, with an abnormal Non-Stress Test (NST) and Bio-Physical Profile (BPP) of 3 or above, cordocentesis for fetal blood gas analysis was performed. In seven cases an immediate post-partum blood sample was taken from the fetal cord for a similar analysis. The two tests gave very similar results. The results showed fetal acidemia (pH 7.09-7.19 and B.E. -10-15) in 4 cases, followed by immediate delivery. In the remaining 5 cases, normal blood gases were evident (pH 7.28-7.35); despite the abnormal NST, pregnancy was allowed to continue for 2 to 7 weeks, under close supervision. At birth, 2 out of 9 newborns were deemed by the neonatologist suffering from asphyxia. Both belonged to the acidemic group of women who were managed by immediate cesarean section. The other 5 fetuses, which were managed expectantly, had normal post-partum blood gases or Apgar score; none had asphyxia. Fetal blood gas analysis, on samples obtained by cordocentesis, provides useful information that can assist in the management of premature fetuses suspected of being distressed, according to their heart traces. Normal fetal blood gases can identify those fetuses falsely identified by the NST as in distress and thereby spare them unnecessary premature birth with its known complications.

[Hypoxic myoglobinemia in severe neonatal disorders of adaptation to extrauterine life]

In two series of newborns needing intensive care the presence, the degree and the prognostic value of myoglobinaemia was examined. In series I. of hypoxic newborns the myoglobinaemia was present even in infants requiring less than 60% O2 therapy. The serum myoglobin value was significantly higher in cases needing oxygen therapy over 60% oxygen. This was most pronounced in the critically severe and progressive cases. In series II. of 34 consecutive cases of hypoxic newborns exceeding 7 nM/l proved to have a prognostic value indicating critically severe course or fatal outcome of the disease. The myoglobinaemia observed in the present study may explain the effectivity of the peritoneal dialysis therapy introduced previously by us in severe hypoxic newborns. This possibility was supported by further observations on the transperitoneal passage of myoglobin in 4 renal hilus ligated and peritoneally dialyzed newborn piglets. In conclusion, early detection of the elevated myoglobinaemia in severely hypoxic newborns has a definite prognostic value and its degree can be used in the indication of peritoneal dialysis.

Prediction of acute renal failure after birth asphyxia

Twenty-one babies of 34-41 weeks' gestational age with birth asphyxia (5 minute Apgar score less than or equal to 5 or umbilical artery pH less than or equal to 7.2) were studied during the first two days of life to find out whether the urinary excretion of tubular markers of renal function is of value in the early diagnosis of acute renal failure. Urinary retinol binding protein, myoglobin, and N-acetyl-beta-D-glucosaminidase (NAG), expressed as a ratio with urinary creatinine, were measured and excretion profiles repeated at 3-6 days in 15 infants and at 7-14 days in 11 infants. Plasma creatinine concentration, creatinine clearance, plasma myoglobin concentration, and fractional sodium excretion were measured where possible in asphyxiated infants. Control data were obtained from 50 healthy infants: 28 gave urine samples alone, 17 urine and blood, and five blood alone. Normal urinary values were derived from 17, 25, and three infants, respectively, for the three time periods. The number of control samples was limited for ethical reasons. Four asphyxiated infants had acute renal failure (group 1), four had tubular dysfunction without glomerular disturbance (group 2) and 13 had normal renal function (group 3). Group 1 were clearly identified by greatly increased urinary retinol binding protein (greater than 27,000 micrograms/mmol creatinine) and myoglobin (greater than 1500 micrograms/mmol creatinine) excretion measured in the first two days of life. In control infants the range of excretion of retinol binding protein within the same time period was 3 to 967 micrograms/mmol creatinine and urinary myoglobin was undetectable. Excretion of NAG failed to discriminate between groups 1 and 2. Acute renal failure occurred only in infants who had heavy myoglobinaemia. Tubular dysfunction in group 2 was transient and not accompanied by plasma electrolyte disturbances. We conclude that measurement of urinary excretion of retinol binding protein or myoglobin after birth is helpful in the early diagnosis of acute renal failure.

[Effects of intra-partum stress on lipid metabolism. Adaptation of plasma lipid transport systems in neonates]

Intrapartum asphyxia modifies lipoprotein cholesterol distribution with possible repercussions related to membrane structures and its metabolic functions. We have studied plasma lipid profile and plasma lipoproteins cholesterol distribution in cord blood from 115 newborn infants and 72 pregnant women at delivery.

RESULTS AND DISCUSSION

newborn infants with perinatal asphyxia (n, 48; pHua less than 7.20) have a higher cord blood triglyceridemia and lower plasma HDL-cholesterol, associated to high significant concentrations of atherogenic ratios (CT/HDLc, LDLc/HDLc) than normal newborn infants (n, 67; pHua = 7.20) [TG, 54.81 +/- 2.96 mg/dl vs 45.74 +/- 2.10 mg/dl (p less than 0.005); CT/HDLc, 24.00 +/- 1.30 mg/dl vs 29.62 +/- 1.12 mg/dl (p less than 0.05); LDLc/HDLc, 1.38 +/- 0.10 vs 1.07 +/- 0.06 (p less than 0.01)]. The highest triglycemia and atherogenic ratios in the acidotic newborn infants reveal deep changes in "esterified cholesterol/binding proteins" system, whereon "Apo A1-LCAT-Apo D" molecular complex binding HDL participate. More studies must be done to understand well this phenomenology. Furthermore, at delivery, pregnant women, that their newborn infants suffer an intrapartum hypoxia, had lower lipidemia than those who had newborn infants with intrapartum physiological stress.

Concentration of twelve plasma proteins at birth in very low birthweight and in term infants

Plasma samples obtained at birth from 70 very low birth weight (VLBW) infants (gestational age 24 to 34 weeks) and from 20 term infants were analysed for concentrations of 12 different proteins. The plasma concentrations of albumin, transthyretin (TTR), retinol-binding protein (RBP), vitamin D-binding protein, apolipoprotein A I, fibronectin, orosomucoid and alpha 1-antichymotrypsin were significantly lower in the VLBW infants than in the term infants, whereas the values of alpha-fetoprotein (AFP) were significantly higher in the VLBW infants. No differences were found between the two groups for apolipoprotein A II, apolipoprotein B and transferrin. Birth asphyxia and sex had no influence on the measured plasma protein concentrations. The plasma concentrations of apolipoprotein A I and A II were significantly lower in small-for-gestational age (SGA), VLBW infants compared with appropriate-for-gestational age (AGA), VLBW infants. Possible acute inflammation (defined as raised concentrations of orosomucoid or alpha 1-antichymotrypsin) was associated with significantly higher values of vitamin D-binding protein in both VLBW and term infants, suggesting that this protein may act as an acute phase protein in newborn infants.

Vasoparalysis associated with brain damage in asphyxiated term infants

The relationship of cerebral blood flow to acute changes in arterial carbon dioxide and mean arterial blood pressure (MABP) was determined during the first day of life in 19 severely asphyxiated term infants supported by mechanical ventilation. For comparison, 12 infants without perinatal asphyxia were also investigated. Global cerebral blood flow (CBF infinity) was determined by xenon 133 clearance two or three times within approximately 2 hours. During the cerebral blood flow measurement, the amplitude-integrated electroencephalogram and visual-evoked potential were recorded. Changes in arterial carbon dioxide pressure followed adjustments of the ventilator settings, whereas MABP fluctuated spontaneously. Arterial oxygen pressure and blood glucose concentration were in the normal range. Five of the asphyxiated infants had isoelectric electroencephalograms and died subsequently with severe brain damage. They had a high CBF infinity (mean 30.6 ml/100 gm/min) and abolished carbon dioxide and MABP reactivity. Lower CBF infinity (mean 14.7 ml/100 gm/min) and abolished MABP reactivity were found in another five asphyxiated infants with burst-suppression electroencephalograms in whom computed tomographic or clinical signs of brain lesions developed. The carbon dioxide reactivity was preserved in these infants. In the remaining nine asphyxiated infants without signs of central nervous system abnormality, carbon dioxide and MABP reactivity were preserved, as was also the case in the control group. We conclude that abolished autoregulation is associated with cerebral damage in asphyxiated infants and that the combination of isoelectric electroencephalograms and cerebral hyperperfusion is an early indicator of very severe brain damage.

Postnatal changes in serum immunoreactive erythropoietin in relation to hypoxia before and after birth

To assess the immediate postnatal changes of serum immunoreactive erythropoietin (EP) in infants born after acute or chronic fetal hypoxia, and to estimate the rate of EP disappearance, we studied EP concentration, measured by double-antibody radioimmunoassay, in cord venous plasma and in serum at a mean age of 8 hours in a control group (n = 9) and in three patient groups: (1) infants with polycythemia (n = 10), (2) infants born to mothers with preeclampsia of pregnancy, without (n = 22) or with (n = 11) acidosis at birth, and (3) infants with acute birth asphyxia (n = 19), seven of whom had postnatal hypoxia. In all patient groups, cord venous EP was elevated in comparison with values in control infants. No change was found in EP level between birth and 8 hours in control infants (geometric mean in cord and 8-hour sample: 20 and 16 mU/ml, not significant) or in acutely asphyxiated infants with postnatal hypoxia (122 and 72 mU/ml, not significant), whereas the EP level decreased in all other groups: infants with polycythemia (123 to 24 mU/ml, p less than 0.001), nonacidotic infants (78 to 26 mU/ml, p less than 0.001) and acidotic infants (176 to 38 mU/ml, p less than 0.001) of the preeclampsia group, and acutely asphyxiated infants without postnatal hypoxia (58 to 30 mU/ml, p less than 0.001). The mean (+/- SD) half-time of EP disappearance was 2.6 +/- 0.5 hours in infants with polycythemia and 3.7 +/- 0.9 hours in infants of the preeclampsia group.

Diminished splenic function in asphyxiated term infants

The effect of birth asphyxia on splenic function has not previously been investigated. We performed quantification of pocked erythrocytes to assess splenic function in 10 term infants with abnormally low Apgar scores and clinical symptoms of birth asphyxia and in 10 healthy term control infants. The mean pocked erythrocyte count of the asphyxiated infants at day 1 (33.9% +/- 6.8 [SD]) was greater than that of the control infants (21.4% +/- 6.3) (P less than .01). By day 3 the mean pocked erythrocyte count of the asphyxiated infants (25.2% +/- 8.4) was still elevated but approaching that of the control infants (18.8% +/- 5.5) (.05 less than P less than .10). In summary, birth asphyxia was associated with an elevation of pocked erythrocytes and decreased splenic function.

[Plasma concentration of atrial natriuretic peptide, vasopressin and aldosterone in the umbilical cord blood: its relation to perinatal asphyxia]

Aldosterone, vasopressin (AVP) and atrial natriuretic factor (ANF) plasmatic concentrations were determined in cord arterial blood from 42 newborns to term: 29 healthful and 13 with perinatal asphyxia. Control group showed plasmatic levels (pg/dl) AVP, aldosterone and ANF significantly lower than perinatal asphyxia newborns group (AVP: 2.27 +/- 1.43 vs 4.26 +/- 2.86; aldosterone: 1.113 +/- 384.79 vs 1,540.38 +/- 595.96; ANF: 2.27 +/- 1.43 vs 4.26 +/- 2.86, respectively (p less than 0.05). We found an inverse correlation between umbilical arterial pH vs AVP, aldosterone and AFN, and a direct correlation between ANF vs aldosterone. Perinatal asphyxia induces secretion of the three studied hormonal factors, likely as a physiologic mechanism of fetal adaptation to hydroelectrolytic and hemodynamic changes which occur during the asphyxia.