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Biomedical subjects

V Kariniemi

Publications and source records attributed to V Kariniemi.

13 recordsLinked to original sources

Significance of meconium staining of the amniotic fluid.

The study was conducted to determine the significance of meconium staining and more specifically its association with fetal heart rate patterns. Five hundred and one patients in labor were examined, 106 of whom had meconium stained amniotic fluid. A multivariate analysis of the data was performed by logistic regression analysis using meconium staining as the dependent variable. The determinants of meconium in the amniotic fluid were gestational age, base deficit, calcified placenta, late decelerations and placental weight. The following variables had no effect on the occurrence of meconium: maternal age, type of risk, parity, fetal sex, duration of labor, duration of the second stage of labor, entanglement of the umbilical cord, FHR variability, variable decelerations, oxytocin usage, type of anesthesia, maternal smoking and alcohol consumption habits. In conclusion, meconium in the amniotic fluid seems to be associated with placental rather than with umbilical insufficiency.

Amniotic Fluid

Maternal smoking and alcohol consumption as determinants of birth weight in an unselected study population.

A prospective study was conducted to determine the effects of maternal smoking and alcohol consumption during pregnancy on the birth weight of fetuses in an unselected study population. Several confounding factors were taken into account. The main factors associated with an increase of birth weight of both sexes were gestational age at birth and parity. Both maternal smoking and maternal alcohol consumption during pregnancy had the effect of decreasing the birth weight of female fetuses, whereas smoking, but not alcohol, had a decreasing effect on birth weight of male and female fetuses.

Alcohol Drinking

Intramuscular pethidine (meperidine) during labor associated with metabolic acidosis in the newborn.

Analyses of fetal heart rate (FHR) variability, visual evaluation of FHR decelerations, and respiratory gas analyses of the umbilical vein were performed in 27 labors, where one dose (50 or 75 mg) of intramuscular pethidine was used for pain relief, in 47 labors with one paracervical blockade (6 ml 0.5% marcaine) and in a control group of 135 labors without any pain relief. Umbilical vein pH, standard bicarbonate and base excess were lowest in the pethidine group and highest in the PCB group. The duration of labor was shortest in the control group, but there was no difference in the duration of labor of the two anesthesized groups. Intramuscular pethidine seems to associate with umbilical metabolic acidosis and PCB should be preferred to it, when an obstetrician is available.

Acidosis

Stress of delivery and plasma endorphins and catecholamines in the newborn infant.

Cord plasma levels of endorphins and catecholamines were correlated with the values of cord blood gas analysis and with hemodynamic parameters in 11 newborns (group A) delivered by elective cesarean section and in 18 newborns (group B) born spontaneously by vaginal route. All infants were in a good condition. No statistically significant differences were found in the mean cord plasma levels of adrenaline (A), noradrenaline (NA) and immunoreactive beta-endorphin (ir beta-E) between groups A and B. After spontaneous labor in group B a highly significant negative correlation was found between plasma NA level and pH and a positive correlation between NA and carbon dioxide tension in cord arterial blood and between NA and the short-term variability of the fetal heart rate before birth. Cord plasma A and ir beta-E did not show such correlations. These findings show that cord plasma level of NA is a sensitive indicator of minor stress during normal labor. After birth, during the first two hours of life, the mean plasma level of ir beta-E decreased in group B after vaginal delivery, but remained at a higher level in group A after elective cesarean section. This shows that the mode of delivery influences the neonatal endorphin secretion.

Blood Gas Analysis

Abdominal electrocardiography in intrapartum fetal heart rate monitoring.

Abdominal fetal electrocardiography (AFECG) as a means of intrapartum fetal heart rate (FHR) monitoring was studied in 700 consecutive labors in a small hospital. Sixty-eight pregnancies were excluded from the study because of the elective cesarean section or because labor was too short for electronic monitoring. AFECG succeeded (at least 30% of fetal heart intervals obtained) throughout labor in 99 of 632 monitored labors (16%). Ultrasound was needed in six cases (1%). The rest (527) were monitored first with the use of AFECG, and later with the use of direct FECG. The mean beat-to-beat variation of FHR (differential index) during last two hours of labor measured from AFECG signal was similar to that measured from AFECG and direct FECG. Hence the same reference values of the differential indices for both methods can be used. The mean long term variation (interval index) measured from AFECG was lower than that measured from abdominal and direct FECGs consecutively. Ultrasound is rarely needed during labor, and it should be avoided except in breech presentations, in association with low placentas and twins, if recording of AFECG fails.

Electrocardiography

Analysis of neonatal heart rate variability by a microprocessor-based on-line system.

The effects of different rejection logic limits on the results of analysis of neonatal heart rate variability from electrocardiograms by a microprocessor-based system were studied on fourteen infants after normal labor and on ten infants after elective cesarean section. In addition to the infant's movements and crying, two further main sources of error in the calculation of variability indices were detected: premature beats and problems in the shape of QRS complexes in a neonatal electrocardiogram. No noteworthy problem was observed in the calculation of the interval index (II), which describes the long term variability of heart rate. In the calculation of the differential indices (DI), which describe the short term component of heart rate, distorted QRS complexes created very high DIs when the rejection logic was ten beats per minute (bpm). When stricter rejection limits were used (five bpm), the DI values even in these cases fell within the normal range. The DI values calculated using a rejection limit of five bpm were always lower than those calculated using a rejection limit of ten bpm, but the reference values of neonatal II and DI after normal labor were similar to those presented previously using a rejection limit of ten bpm. In conclusion, the neonatal electrocardiogram appears to be a noisy signal, comparable with the abdominal fetal electrocardiogram, and strict rejection limits are useful in processing it for indices of variability.

Computers

Quantification of fetal heart rate variability by magnetocardiography and direct electrocardiography.

A computer method for quantification of fetal heart rate (FHR) variability from fetal magnetocardiography during pregnancy and from direct fetal electrocardiography during labor is presented. It is based on statistical analysis of the QRS interval sequences. Beat-to-beat variation is characterized by a differential index (DI) and long-term variation by an interval index (II). The effect of the sample time on the DI is minimal, and hence the DI can be calculated from rather short samples. The II is more sensitive to FHR trends and should be calculated from longer samples, but between the periodic changes, accelerations, and decelerations. Variable amounts of detection pulses are lost in both methods. The DI is sensitive to the missing intervals; no analysis result should be accepted if the number of lost intervals exceeds 10 per cent. The II is less sensitive to the number of missing intervals. The means and standard deviations of the variability indices for eight fetuses during pregnancy and for five fetuses during labor are presented.

Computers

Instantaneous fetal heart rate monitoring by electromagnetic methods.

Fetal magnetocardiography (FMCG) is a new complementary external method for accurate antepartal FHR recording. Because of the low magnetic noise level required it is not yet suitable for routine hospital use. Fifty-six simultaneous FMCG and external FECG measurements were made in order to compare these methods for instantaneous FHR recording. The error of the FHR value obtained with the instrumentation described is less than 1 per cent. Our results show that FMCG can be used for FHR processing from week 30 of gestation until term. Thirty-five of the measurements were done during this period. From these, a readable FHR curve was obtained in 21 cases with FMCG and in 12 cases with external FECG. The maternal complexes were always present in the FECG, but in only 15 of the recorded FMCG's.

Electrocardiography

Detection of fetal QRS-complexes by external methods.

A new method is presented for detection of the QRS complexes and the fetal heart rate from the fetal magnetocardiogram and from the fetal electrocardiogram. In the method, the amplitude, the polarity and the shape of the QRS complex are tested. By using the described equipment it is possible to detect all consecutive heart beat intervals from a fetal electrocardiogram with less than 1% error in timing. When an external fetal electrocardiogram was used for testing, generally slightly over 10% of the QRS complexes were lost since they were simultaneous with the maternal complexes. In addition, complexes were also lost due to noise.

Electrocardiography