Neonatal Blood Samples Research Articles

Frequency of Immune Thrombocytopenia in Newborns: A Prospective Study

AbstractThrombocytopenia is a common condition in distressed newborns, but little is known about thrombocytopenia in an unselected cohort of neonates. In an attempt to address this issue, a multicenter prospective study was conducted in three obstetrical wards of AP-HP in Paris. We found the frequency of neonatal thrombocytopenia (<150 × 109/L) to approximate 0.9% (48 of 5,632 appropriate samples). An immune mechanism was likely to be the cause of thrombocytopenia in 10 of the 33 cases studied, implying an incidence of 0.3% of immune neonatal thrombocytopenia in the general population. The frequency of alloimmune thrombocytopenia was 1.5/1,000 liveborn neonates, and 1/1,000 when considering anti–HPA-1a allo-immunization. Because thrombocytopenia, whatever its cause, was often silent and delayed, it appears that the only way to detect neonatal thrombocytopenia in time to prevent its potential disastrous complications would be to perform a systematic neonatal blood sampling for platelet count. All cases of ascertained thrombocytopenia should then be screened for an immune mechanism to enable early detection of autoimmune diseases in mothers and careful monitoring of subsequent pregnancies and deliveries, leading to appropriate prevention of potential severe deleterious effects in the offspring.

Études exploratoires des relations intersensorielles olfaction-douleur

This study investigates the effects of various odorants on the behavioural responses to pain in human newborns and adult mice. Human babies were observed during the neonatal blood sampling. During the blood sampling episode, the duration of crying was not influenced by the nature of the odors (maternal milk, familiar powder milk, physiological serum). Yet, after the sampling the crying duration of babies exposed to the odor of maternal milk was significantly reduced. The mice were submitted to electrical shocks delivered through the floor of their cage. The adult mice were submitted to pleasant, unpleasant or neutral odors during the first twenty one days of life. The mice that were exposed to pleasant odors presented less intense behavioral reactions to pain (the decrease was measured as a lower frequency in shrieking) whereas this reaction was slightly increased when the odor was unpleasant. The neutral odor had no effect on the response to pain. These results are discussed in terms of the effect of olfactory stimulation on the pain integration and on attention processes.

Maternal-fetal hemorrhage: a reappraisal.

To determine the frequency of maternal-fetal hemorrhage at or above 1 microliter of maternal whole blood. Seventy-three mothers whose red blood cells bore an Rh antigen (Rh D, Rh c, Rh E) that was absent on red blood cells of their newborns were identified and a new cytological method, the Kleihauerimmunogold-silver-staining technique, was applied on the blood of their neonates to detect and quantify maternal red blood cells. Stringent precautions were taken to avoid contaminations of neonatal blood samples by adult red blood cells. Maternal red blood cells were present in 3 newborns, a frequency of 4% (95% Cl: 1-11%), and the estimated volumes of hemorrhage were 0.8, 1.5, and 101 microliters of maternal whole blood. No obstetric factor was clearly associated in this limited study with the occurrence of maternal-fetal hemorrhage. Mother-to-fetus microtransfusion greater than 1 microliter is infrequent at or near delivery, and it may be observed after an uncomplicated pregnancy and vaginal delivery.

INFANTS OF DIABETIC MOTHERS (IDM), AS WELL AS LARGE FOR GESTATIONAL AGE INFANTS (LGA) REQUIRE DIFFERENT GUIDELINES FOR PARTIAL EXCHANGE TRANSFUSION(P.Ex. T.) † 1175

Variability in whole blood viscosity is dependent primarily on hematocrit(hct) levels, but red cell factors such as deformability and aggregability, and variations in plasma proteins also play a role. Previous studies had suggested that at a laboratory-standardized hct (50%), symptomatic IDM may have higher viscosity levels than healthy controls. We did a retrospective review of results from neonatal blood samples submitted to our laboratory during the past 5 years for viscosity determinations because of polycythemia and/or suspicion of hyperviscosity.119 neonatal records were available for review. The submitted blood samples were categorized into specific hct groups from 58% to 68%. Each hct group was divided into 2 subgroups: A) Infants who were known to be IDM, plus LGA infants not specifically documented as IDM. B) The remaining neonates who served as controls. Mean viscosity values of group A and of group B at each hct and at specific shear rates were compared by 2-way ANOVA. At each shear rate (90 and 11.25 sec-1) group A (IDM + LGA) was significantly greater than group B (control) (p<0.001). Mean viscosity values (centipoise) for the specified hct. groups are shown below at a shear rate of 90 sec-1: Table

Maternal-Fetal Hemorrhage: A Reappraisal

To determine the frequency of maternal-fetal hemorrhage at or above 1 μl of maternal whole blood. Methods: Seventy-three mothers whose red blood cells bore an Rh antigen (Rh D, Rh c, Rh E) that was absent on red blood cells of their newborns were identified and a new cytological method, the Kleihauerimmunogold- silver-staining technique, was applied on the blood of their neonates to detect and quantify maternal red blood cells. Stringent precautions were taken to avoid contaminations of neonatal blood samples by adult red blood cells. Results: Maternal red blood cells were present in 3 newborns, a frequency of 4% (95% Cl: 1-11%), and the estimated volumes of hemorrhage were 0.8, 1.5, and 101 μl of maternal whole blood. No obstetric factor was clearly associated in this limited study with the occurrence of maternal-fetal hemorrhage. Conclusions: Mother-to-fetus microtransfusion greater than 1 μl is infrequent at or near delivery, and it may be observed after an uncomplicated pregnancy and vaginal delivery.

Mother-to-Child Transmission of the Human Immunodeficiency Virus

Heterosexual transmission is responsible for most infection with the human immunodeficiency virus (HIV). The increase in pediatric HIV infection has had a substantial impact on childhood mortality, both in industrialized countries, such as the United States,1 and in developing countries.2 In some areas in sub-Saharan Africa, 10 to 30 percent of pregnant women are HIV-infected, and infection is now spreading to parts of Southeast Asia. Reporting of pediatric cases of the acquired immunodeficiency syndrome (AIDS) to public health authorities, registers of HIV-infected children, and unlinked anonymous testing of antenatal and neonatal blood samples make it possible to monitor the prevalence . . .

Neonatal jaundice with reference to aflatoxins: an aetiological study in Zaria, northern Nigeria.

Two prospective studies were undertaken to determine a possible relationship between perinatal aflatoxin exposure and neonatal jaundice. First, cord blood samples from 37 neonates who subsequently developed jaundice and from 40 non-jaundiced (control) babies were analysed for six major aflatoxins and aflatoxicol. Peripheral blood samples of both groups were also analysed postnatally for aflatoxins. In a second study, serum aflatoxin levels of 64 jaundiced neonates admitted from outside the hospital were compared with levels in 60 non-jaundiced control babies. Aflatoxins were detected in 14 (37.8%) cord blood samples of jaundiced neonates and in nine (22.5%) of the controls. The mean cord aflatoxin concentration was highest in jaundiced neonates with septicaemia, but the difference was not statistically significant. The frequency of detection of aflatoxins in peripheral blood was not significantly different in jaundiced and non-jaundiced babies. Aflatoxins were detected in the blood of over 50% of neonates with jaundice of 'unknown' aetiology. There was no correlation between severity of hyperbilirubinaemia and serum aflatoxin levels. Further studies are needed to determine the extent of pre- and postnatal exposure to aflatoxin in Nigerian infants and the effects of such exposure on fetal and neonatal health.

Near-patient measurements of methemoglobin, oxygen saturation, and total hemoglobin: evaluation of a new instrument for adult and neonatal intensive care.

a) To evaluate the performance of a compact, new instrument that uses disposable cuvettes to measure total hemoglobin concentration, oxygen content, and the relative concentrations of oxy- and methemoglobin in 50-microL blood samples; b) to determine whether the instrument can be used for near-patient assessment of methemoglobinemia; and c) to ascertain whether problems commonly encountered in neonatal blood samples affect the instrument's performance. Prospective study, in which the test instrument was compared with a standard method. Samples of whole blood with and without bilirubin, fetal hemoglobin, and hemolysis were analyzed on the new (test) instrument and on a widely used cooximeter (OSM3 hemoximeter, Radiometer; reference instrument). In vitro analyses of blood samples in clinical and university laboratories. There was a close linear correlation between the methomoglobin measurements of the test instrument and those measurements of the reference instrument (slope = 0.989; r2 = .989). The average difference in mean assay values between the reference instrument and the test instrument was -0.59%, i.e., < 1% methemoglobin. Repeated measurements indicated the precision was 0.5% methemoglobin. Complete hemolysis of the sample reduced the methemoglobin reading by only 0.40%. Adding bilirubin (10 to 11 mg/dL [171 to 188.1 mumol/L]), increased the methemoglobin reading by 0.23%, increased the oxyhemoglobin reading by 0.45%, and increased total hemoglobin by 0.21 g/dL. Fetal hemoglobin also had minimal effects on the readings. The test instrument is fast and easy to operate. No sample preparation or pipetting is required. To operate the instrument, the user simply connects a syringe containing the blood sample to one of the disposable cuvettes, injects 50 microL of blood into the cuvette, and inserts the cuvette into the instrument. The test instrument automatically detects the presence of the cuvette, analyzes the sample, and displays the results in < 10 secs. The findings in this study indicate that the test instrument has sufficient accuracy for near-patient testing in intensive care units. The errors introduced by hemolysis, fetal hemoglobin, and bilirubin were too small to be of clinical importance. Thus, the test instrument is essentially unaffected by complications commonly encountered in neonatal blood. The capacity of the test instrument to measure methemoglobin makes it particularly useful if inhaled nitric oxide therapy becomes a standard clinical practice.

Monoclonal antibody immunoassay for the identification of hemoglobin variants in neonatal screening

Background: Four monoclonal antibody assay kits (HemoCard) for the identification of hemoglobins A, S, C and E were evaluated. Current methods used to screen newborns for hemoglobin variants are based on charge separation techniques. Unlike the charge separation methods, these kits require no instrumentation. The suitability of HemoCard for the confirmation of results from charge separation screening methods was examined. Methods: Neonatal filter paper blood samples, previously analyzed in several newborn screening labs, were reanalyzed using the various HemoCard kits. These samples included homozygotes and heterozygotes for hemoglobins A, S, C and E. Also, over 20 rare variants were used to test the specificity of the HemoCard assays. Other evaluations included tests for detection limit, sample concentration, reproducibility and temperature. Sample stability was also examined. Results: All results ( n = 2305) from the filter paper blood samples were correctly confirmed by HemoCard. Differentiation of heterozygotes and homozygotes for hemoglobin A was possible by use of HemoCard A, except in samples containing hemoglobin E. None of the rare hemoglobin variants tested interfered with the HemoCard S, C and E assays. These kits gave a positive result when the variant concentration was at least 1.5% of the total hemoglobin present. The HemoCard assays detected various hemoglobins over a wide range of concentrations. All of the assay kits gave positive results on the 15 replicates of all samples tested for reproducibility. There was no effect of temperature in the range of 4–37°C. All samples tested for room temperature stability continued to exhibit the same results for at least 6 months. Conclusions: The monoclonal antibody conjugates used in the HemoCard assays were specific for the targeted variants. Since the HemoCard A monoclonal antibody is directed to the β6 epitope, it also binds to hemoglobin variants that have intact β6 epitopes which include Hb E. The HemoCard assays were found to be extremely beneficial in confirming the absence and presence of Hb S, C and E in neonatal blood spot samples.

Use of Anonymous Newborn Serosurveys to Evaluate Antenatal HIV Screening Programmes

To evaluate the extent to which antenatal HIV screening programmes identify HIV infected women who go to term. Comparison of results of two surveillance systems. An anonymous neonatal HIV serosurvey was used to estimate the numbers of HIV infected women giving birth; reporting by obstetricians was used to assess the proportion who had been identified. Three Thames regions. 729,105 neonatal blood samples were tested, of which 484 were HIV seropositive. Newborn HIV seroprevalence is increasing, at different rates, in inner London, suburban London, and in non-metropolitan districts. During the past four years the proportion of infected women who have been identified before delivery is 16.9%, but less than half of these were diagnosed during pregnancy. In 1993 only five of the 128 (4%) previously undiagnosed infected women delivering babies were identified by antenatal screening. Despite increased emphasis on antenatal testing for HIV in areas of higher prevalence the number of undiagnosed women delivering babies continues to increase. Consideration should be given to alternative strategies for offering antenatal HIV testing. Antenatal screening programmes should be monitored continuously by comparing anonymous neonatal seroprevalence with clinical reports from obstetricians.

Role of lipid peroxidation in metalloporphyrin-mediated phototoxic reactions in neonatal rats.

Our group previously demonstrated dose-dependent mortality in neonatal rats treated with tin protoporphyrin and light. We hypothesize that lipid peroxidation may be responsible for the toxic effects of photosensitizing metalloporphyrins. Neonatal rat blood samples with or without metalloporphyrins (40 mM) were exposed to cool white light (20 microW/cm2/nm) for 30 min at 37 degrees C. In the in vivo model, neonatal rat pups were given injections of 40 mumol of either tin protoporphyrin (4 mM), zinc protoporphyrin/kg body weight, or saline and placed over cool white light. The control animals were similarly treated but kept in the dark. After 3 h, the animals were killed, and their tissues were analyzed for malondialdehyde, conjugated dienes, and disappearance of polyunsaturated fatty acids as indices of lipid peroxidation. In all cases, the known photosensitizer tin protoporphyrin was associated with increased conjugated dienes in the liver and disappearance of polyunsaturated fatty acids and increased malondialdehyde in the liver and brain when animals were exposed to light. Zinc protoporphyrin was not associated with increased lipid peroxidation in the light except in the case of blood in vitro where malondialdehyde levels increased. We conclude that lipid peroxidation plays a role in metalloporphyrin-mediated phototoxicity in neonatal rat tissues.

Arterial blood sample collection from the newborn calf

Measurements of arterial blood gas tensions and acid-base status provide a means of assessing how well the respiratory system is functioning. This information is essential for thorough evaluation of a compromised neonatal calf but arterial blood sampling is difficult immediately after birth. A technique for collecting blood from the brachial artery of the newborn calf is described. This technique, which uses an easily located site, has been successfully used in field studies to determine arterial blood gas values in such calves.

Three years' diagnostic experience with direct karyotyping of neonatal blood

Three years' experience with direct karyotyping of cord blood and neonatal venous blood is recorded. Fifty cord blood samples have been processed and 39 yielded satisfactory diagnostic results. Eight of 14 neonatal venous blood samples yielded diagnostic chromosome results after direct karyotyping. Factors which affected success are discussed.

An evaluation of the Coulter VCS differential counter.

An evaluation of the Coulter VCS (volume, conductivity, light scatter) automated differential counter demonstrated satisfactory correlations with manual 800-cell differential counts for neutrophils, lymphocytes, monocytes and eosinophils. For the detection of abnormal cells, 12.2% of samples gave false-negative results on the VCS, and 13.4% gave false-positive results. However, only 0.8% of the false-negatives would be expected to be picked up by a standard 100-cell manual differential count. Carry-over accorded to manufacturer's specifications and throughput was 60 samples/h. Reference normal ranges have been established and the instrument's precision and performance with leucopenic and neonatal blood samples assessed.

Direct isolation of coagulase-negative staphylococci from neonatal blood samples

Coagulase-negative staphylococci (CNS) were isolated by direct inoculation of anticoagulated whole blood onto agar from 14 (41.2%) of 34 episodes (30 neonates) of suspected bacterial infection, associated with isolation of CNS from the same blood sample by broth-dilution blood cultures. The equivalent of more than 1000 cfu ml −1 were isolated from four samples (four neonates); the range of counts was 1–103 cfu 25μl −1. There was a statistically significant association between isolation of CNS by direct agar inoculation and a raised C-reactive protein level and/or a positive nitroblue tetrazolium test and with the use of an intravascular catheter when compared to those episodes where CNS were isolated from broth blood cultures only. This simple procedure provides an estimate of the number of CNS in the blood of a neonate with suspected bacteraemia and may help to corroborate a diagnosis of CNS bacteraemia.

Autologous mixed lymphocyte reaction in human neonatal lymphocytes

Human neonatal mononuclear cells were examined to determine their ability to participate in an autologous mixed lymphocyte reaction (AMLR). Stimulator cells were isolated by plastic adherence and nylon wool adherence. The nylon wool-nonadherent cells were used as responder cells. In 10 of 10 neonatal samples and 6 of 7 adult samples, a significant AMLR was present when plastic-adherent cells were used as stimulators. Neonatal blood showed a mean increase in proliferation of 7.6 (3.6–14.9), while adult cultures showed a mean stimulation index of 11.8 (1.0–39.0). When nylon wool-adherent cells were used as stimulator cells, only 2 of 7 neonatal blood samples and 1 of 5 adult blood samples showed a significant AMLR. When recombinant interleukin 2 (IL-2) was added to AMLR cultures of plastic-adherent cells and nylon wool-nonadherent cells, a mean augmentation of 12.0 was seen in the neonatal AMLR, while the adult cultures were augmented by a mean response of 4.1. Addition of IL-2 to nylon wool-nonadherent cells alone produced a 5.9-fold increase in adult cells, while neonatal cells showed an 85.8-fold mean increase in proliferation. The results suggest that autoreactive T cells are present in neonatal blood and that these cells can be activated by plastic-adherent autologous cells. However, neonatal and adult nylon wool-adherent cells do not consistently activate autoreactive T cells.

Clinical application of a new glucose analyzer in the neonatal intensive care unit: Comparison with other methods

We evaluated the operation of the Yellow Springs Instrument Co. (YSI) glucose analyzer (model 23A) by clinical nurses for the measurement of blood glucose in the intensive care nursery. In vitro performance was determined with the use of aqueous standards; with a 2-point calibration of 0.0 and 200 mg/dl, a precision of better than 1.0% of each standard (25, 50, 100, 200 mg/dl) was achieved, and the linearity was excellent (Y = 0.99X - 0.49, r = 0.99). The YSI correlated well with a manual spectrophotometric glucose oxidase method (r = 0.99) and the Kodak Ektachem analyzer (r = 0.98) using human umbilical cord blood samples. Five trained clinical nurses performed all YSI and glucose reagent strip analyses, including all in vitro and patient samples. Four reagent strip methods were compared with the YSI from 104 neonatal heel-stick blood samples: Glucometer II with memory (r = 0.73), Glucostix (r = 0.74), Dextrostix (r = 0.70), and Chemstrip bG (r = 0.83). We conclude that clinical nurses can and do learn to use the YSI with excellent precision and that the YSI represents an improved method for measuring glucose concentrations in the newborn intensive care nursery.

Fetal Goitrous Hypothyroidism

We present a first case in whom fetal hypothyroidism with goiter was both successfully diagnosed and treated in utero. An obstetrical sonogram at 33 weeks revealed a bilobed fetal neck mass, compatible with enlarged thyroid gland, associated with neck hyperextension, reduced gastric fluid, and polyhydramnios. Umbilical blood sampling after volume reduction amniocentesis confirmed fetal hypothyroidism with a euthyroid mother. Fetal T&lt;sub&gt;4&lt;/sub&gt; measured 1.3 μg/dl, free T&lt;sub&gt;4&lt;/sub&gt; 0.3 ng/dl, and thyroidstimulating hormone 186 μU. Intra-amniotic levothyroxine, 500 μg, was given twice with a 14-day interval. The head flexed, gastric fluid increased, and amniotic fluid levels returned to normal. Prenatal (36 weeks) and neonatal blood sampling demonstrated return to euthyroid indices. Ultrasonic estimates of thyroid volume decreased by over 50%. Vaginal delivery at 39 weeks was incomplicated. The newborn appeared normal and is being maintained on thyroid replacement therapy.

Relationship of Pulse Oximetry to Arterial Oxygen Tension in Infants

Pulse oximetry is a useful technique for noninvasive oxygen monitoring in sick infants. We simultaneously measured oxygen saturation by pulse oximetry and on arterial blood samples by co-oximetry as well as PaO2 and the relative content of fetal (F) and adult hemoglobin in order to evaluate the reliability of pulse oximetry. Comparisons were made in triplicate in ten infants with acute cardiorespiratory disease less than 7 days of age and in 11 infants with chronic lung disease greater than 28 days of age. Oxygen saturation pulse oximetry and arterial saturation were well correlated over a wide range of saturation values. In infants with chronic lung disease, PO2 derived from pulse oximetry was within 10 torr of measured PaO2 in 73% of comparisons. In contrast, calculated PaO2 was within 10 torr of measured PaO2 in only 50% of comparisons in patients with acute disorders. The chronic infants all had less than 10% hemoglobin F, but in the acute infants, hemoglobin F ranged from 26% to 83%. Nonetheless, correction of oxygen dissociation curves for type of hemoglobin in these acute infants failed to improve the correlation between calculated and measured PaO2. We conclude that pulse oximetry saturations and their derived PaO2 values correlated well with measured arterial saturation and PaO2 obtained from arterial blood samples in neonates with chronic lung disease and prolonged oxygen dependence. In infants with acute cardiorespiratory problems, pulse oximetry unreliably reflects PaO2, but may be useful in detecting clinical deterioration.

Sources of error in neonatal blood sampling.

Significant underestimation of blood electrolyte concentrations may occur if less than 1 ml of blood is withdrawn from an indwelling arterial line before taking the sample for analysis. Compared with arterial samples capillary samples give significant overestimations of potassium concentration and carbon dioxide tension, and significant underestimation of oxygen tension.