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Biomedical subjects

A Selbing

Publications and source records attributed to A Selbing.

At least 37 records · Page 2Linked to original sources

Evaluation of a new Swedish protocol for alloimmunization screening during pregnancy.

Screening protocols for alloimmunization during pregnancy usually make a difference between primi- and multigravidae as well as between Rh(D) negative and Rh(D) positive pregnant women. We have evaluated a new screening program including antibody tests at 25 and 35 gestational weeks only, for all, and regardless of Rh(D) group. During the time period 1983-89, 78,300 consecutive pregnancies were tested. Red cell antibody immunizations were detected in 287 (0.37%) pregnancies subdivided into fourteen different red cell IgG antibody specificities. Significant antibody titers (defined as IAT or enzyme titers > or = 8) were observed in 225 pregnancies, where 127 (56%) were previously unknown. A majority (63%) of the new immunizations occurred among the Rh(D) positive pregnant women. All newborns that needed phototherapy or exchange transfusion due to alloimmunization were recognized at the time of delivery. We conclude that antibody screening tests at 25 and 35 gestational weeks for both Rh(D) negative and positive pregnant women is sufficient, effective and a safe procedure for the fetus as well as for the mother.

Coombs Test↗

Fetal heart rate responses to anemia in Rh isoimmunization.

On 52 occasions 24 Rh immunized women were monitored with a nonstress test (NST) prior to fetal blood sampling. Cardiotocographic characteristics were recorded for each NST. Fetal blood was analysed for hemoglobin and hematocrit. Fetal hemoglobin and hematocrit were positively correlated to long-term variability, acceleration amplitude and negatively correlated to deceleration amplitude (linear regression analysis; p less than 0.05). Decelerations were almost without exception associated with low concentrations of hemoglobin and hematocrit. In fetuses of 32 weeks' gestation or more, a loss of variability (less than or equal to 5 bpm) was associated with severe anemia. Hemoglobin and hematocrit were significantly lower in the group with a pathological NST (n = 15) compared with the group with a normal NST (n = 37) (Mann-Whitney U test; p less than 0.05). The predictive value of a pathological test was 13/15 concerning hemoglobin and hematocrit; whereas, the predictive value of a normal test was poor. A pathological NST, especially when decelerative, is a good predictor of fetal anemia, but a normal NST is no guarantee for a normal blood status.

Anemia↗

Acid-base status in fetal heart blood in erythroblastotic fetuses: a study with special reference to the effect of transfusions with adult blood.

Blood gas levels, pH, and lactate concentration were studied in fetal heart blood on 70 occasions in 26 fetuses with erythroblastosis. A decreasing hemoglobin concentration correlated to a fall in pH (p = 0.006) and bicarbonate (p = 0.015) and to a rise in base deficit (p = 0.002) and lactate concentration (p = 0.05). Twenty of the fetuses underwent 63 intracardiac transfusions. A multivariance analysis for hemoglobin concentration, percentage of fetal to adult blood, and different acid-base parameters revealed a significant correlation between the presence of adult blood and a rise in PO2 (p = 0.047), but failed to demonstrate any correlation to the other studied acid-base variables. Thus the present study suggests that the fetus can compensate for the physiologic properties of adult hemoglobin that are disadvantageous to itself by increasing PO2 and thereby maintaining oxygen supply. The physiologic background and the clinical implication are discussed.

Acid-Base Equilibrium↗

Preparation of packed red cells suitable for intravascular transfusion in utero.

Intra-cardiac transfusion in utero is a recent development in the treatment of erythroblastosis foetalis. As with intra-umbilical cord transfusion, the procedure has been described as having a high risk of complication characterized by bradycardia and cardiac-arrest. Intra-coronary hyperkalemia was suspected as being a major contributing factor towards the complications experienced, particularly by the intra-cardiac delivery. The procedure is warranted, however, in cases where intra-umbilical cord transfusion is not possible. Therefore, studies comparing various methods of preparing packed cells for intravascular transfusion were initiated. The plasma potassium levels of gravity sedimented packed cells and saline washed red cells resuspended in either Ringer's lactate, pooled donor plasma or saline were measured. Products of saline washed/resuspended packed red cells transfused within 2 hours of preparation were found to have low potassium levels while exposing the fetus to minimal risk of transfusion transmitted infection and were therefore selected to be the most suitable product. Using this product, a significant decrease in the incidence of severe bradycardia resulting in cardiac-arrest, following intravascular transfusion (32 procedures) was observed.

Blood Transfusion, Intrauterine↗

Feto-placental blood volume in severely anemic erythroblastotic fetuses.

The feto-placental blood volume was studied using a hemoglobin hemodilution technique in 15 erythroblastotic fetuses at 43 intravascular transfusions. Four severely anemic fetuses (Hb 30 g/l) had significantly larger blood volumes than 11 moderately anemic fetuses (Hb 30-79 g/l), 169 +/- 37 versus 105 +/- 32 ml/kg fetal body weight (p less than 0.001). We speculate that hypovolemia might be an adaptive change to maintain an adequate hemoglobin concentration. An escape of fluid from the intra- to the extra-vascular space will probably compensate for the reduction in total red cell mass and thus slightly increase the hemoglobin concentration. Theoretically, interstitial fluid accumulation will continue until the hydrostatic pressure of the extravascular tissue balances that of the capillary. This compensatory mechanism seems to function until the hemoglobin concentration drops below, 30 g/l, at which point the blood volume will increase, suggesting a change from a hypo- to a hyper-volemic state.

Anemia↗

Fetal growth and fetal glucose and C-peptide levels in relation to the degree of anemia in fetuses affected by rhesus iso-immunization.

Fetal growth rate was determined by measuring the fetal biparietal diameter at 63 two-week time points during the second trimester in 14 patients with severe Rhesus isoimmunization. Growth rate was found to be related to the fetal hemoglobin concentration which was determined at the end of each 2-week period. Fetuses with a hemoglobin concentration of less than 30% of the normal value had a significantly decreased growth rate (p less than 0.01). These fetuses had also reduced C-peptide (p less than 0.05) and increased glucose levels (p less than 0.1) compared with less anemic fetuses. The physiological background to impaired fetal growth in cases of severe fetal anamia at Rhesus iso-immunization is discussed.

Anemia↗

Fetal intracardiac transfusions in patients with severe rhesus isoimmunisation.

Six patients with pregnancies of 19-31 weeks' duration showing evidence of erythroblastosis fetalis were treated with 25 fetal intracardiac blood transfusions. Complications related to the procedure occurred on five occasions in three patients. In two of the six patients the fetus died, but it was unlikely that death was related to the intracardiac transfusions. Fetal intracardiac blood transfusion may result in potentially severe complications but offers an alternative when transfusion cannot be performed into the umbilical cord.

Blood Transfusion, Intrauterine↗

Neurological condition of large-for-gestational-age infants during the newborn period.

Thirty-two large-for-gestational-age (LGA) infants and 46 appropriate-for-gestational-age (AGA) infants used as controls, were investigated. LGA and AGA infants did not differ regarding instrumental deliveries or asphyxia. The infants were examined on the 1st and 5th days after birth with a standardized neurological assessment. The LGA infants showed a significantly delayed neurological adaptation with fewer optimal responses on day one as compared to the AGA infants. These differences were not observed on day five. There were no neurological differences between prenatally and postnatally detected LGA infants. No significant differences were observed regarding parity on maternal complications, neonatal course, and neurological scores of the LGA infants.

Fetal Macrosomia↗

Introduction of a programme for intravascular transfusions at severe rhesus isoimmunization.

Thirty-seven fetuses with severe rhesus isoimmunization with a gestational age of less than 30 week underwent 92 intravascular transfusions. Of these, 77 were intracardiac, 13 umbilical vein and two umbilical artery transfusions. Procedure related complications occurred at eight (10%) intracardiac and at two (14%) umbilical cord transfusions. Reversal of hydrops was observed in 10 of 16 fetuses. The perinatal mortality among transfusion treated fetuses was 8/37 (21%). It is concluded that intravascular, intrauterine transfusion leads to improved results among fetuses with early onset of hydrops. Problems concerning indications and technique are discussed.

Blood Transfusion, Intrauterine↗

Umbilical cord compression diagnosed by means of ultrasound.

Two-dimensional ultrasound in combination with a pulsed Doppler may be used during parturition to distinguish between the various causes of fetal heart decelerations during active labor: "placental insufficiency", umbilical cord compression, and, fetal head compression. One case of umbilical cord compression is presented to illustrate the possibilities.

Adult↗

Which fetal growth charts should be used?

Fetal intra-uterine growth charts are generally based on last menstrual period (LMP) data. Such charts may not really be applicable to infants whose gestational age is ultrasonically determined in early pregnancy. 1369 consecutive singleton pregnancies were studied. All fetuses had their gestational age estimated both by ultrasonic measurement of fetal crown-rump length and from registered last menstrual period data. All infants were weighed at birth as a part of the routine care. The age determination according to the two methods differed in 664 out of 1369 cases and in 516 of these 664 cases the age according to LMP was higher than according to CRL--a highly significant difference (p less than 0.001). Mean values for birth weight were found to be larger when correlated to age in terms of CRL determinations than when related to age as calculated from LMP data. Birth weight also showed a significant increase between 40 and 42 weeks when age was determined ultrasonically. This was not the case when age determination was based on LMP data. The explanation of this fact is that age is overestimated in late pregnancy when calculated from LMP data. These facts ought to be considered when future fetal growth charts are constructed.

Birth Weight↗

Conceptual dating using ultrasonically measured fetal femur length and abdominal diameters in early pregnancy.

The association between fetal anthropometric measurements and conceptual age was determined for the femur length and the mean of two abdominal diameters for conceptual ages between 10 and 20 completed weeks. The conceptual age used for reference was determined by the fetal crown-rump length measured at an earlier examination. Two equations are presented for the calculation of conceptual age from isolated estimations of the femur length or the mean of two abdominal diameters. Mean abdominal diameter and femur length measurement values were found to have similar precisions of dating.

Abdomen↗