Biomedical subjects
Publications and source records attributed to P Kirkinen.
Absence of early-diastolic blood flow velocity was recorded from the umbilical artery of a fetus with severe myocardial and valvular insufficiency. The blood flow at late diastole was normal. This flow pattern may indicate the need for a detailed ultrasonic examination of the fetal heart.
The appropriateness of cesarean section as the route of delivery in pregnancies complicated by fatal fetal abnormalities was evaluated in an obstetric population of 47,924 deliveries during the years 1978-90. The incidence of fatal fetal abnormalities was 0.50% and did not change during the study period. The cesarean section rate was twice that in the whole obstetric population, and the procedure was performed mainly for inappropriate fetal indications. One-third of the sections were caused by antepartum or intrapartum fetal distress. After the advent of sophisticated real-time ultrasound equipment, the obstetric management of those cases seemed to increase, but later the incidence of cesarean sections for fetal indications decreased, from increased experience with assessing the prognosis of malformed fetuses and increased opportunities to examine the fetal karyotype. Some conservatism seems justified when choosing obstetric management of a malformed fetus before large, controlled, clinical studies become available.
The effect of experimental noise exposure (15 minutes of 90-dB white noise via headphones) was examined on systolic, diastolic, and mean arterial pressures; heart rate; and stress hormones (ACTH, cortisol, prolactin, epinephrine, and norepinephrine) in normotensive and hypertensive pregnant women. No significant effects induced by noise exposure could be registered in these variables. Fetal and uterine blood circulation was also examined with a duplex pulsed Doppler system. No changes were seen on the fetal side as measured from the descending aorta in blood flow velocity (cm/second) or pulsatility or resistance indexes in either normotensive or hypertensive pregnancy. The only change observed was an increase in fetal heart rate in normotensive pregnancy. However, this increase could not be confirmed by cardiotocographic registration and is not clinically important. Uterine blood circulation was recorded from the proximal uterine artery on the placental side, and no effect of exposure was seen on pulsatility or resistance indexes.
Prenatal diagnosis of single gene disorders is challenging because of the multidisciplinary diagnostic approach and the genetic counselling needed. Out of 3100 pregnancies of northern Finnish women studied for early detection of congenital defects or genetic disease, 110 were at risk for and 15 were unexpectedly found to carry a fetus with a single gene disorder. Seven of the 21 diseases studied were typically representative of inherited diseases in northern Finland. The diagnostic approaches used included fetal ultrasonography, analysis of the components of the amniotic fluid, fetal enzyme analysis, fetal karyotyping for the fragile X syndrome, and fetal DNA analysis. Altogether, 50 pregnancies were found to be affected; 11 of these were continued because the diagnosis was too late for termination, and seven because the parents wanted it. Prenatal diagnosis of severe hereditary disease can be enhanced by improving the detection of pregnancies at risk, and by developing methods for earlier fetal diagnosis.
Transvaginal ultrasonic monitoring of the lower uterine segment was performed in 15 pregnancies in which the mother had previously had three or more caesarean sections. The typical findings were thinning of the myometrium, asymmetric isthmal structures and ventral ballooning of the isthmus. An image of the other of the two isthmal fenestrations was obtained by ultrasound. The antepartum ultrasonic findings and those found at operation correlated well. Maternal antepartum symptoms, on the other hand, poorly reflected the physical state on the scarred uterine isthmus.
Fetal M-mode echocardiography was performed in 13 pregnancies complicated by intrauterine distress. Absent end-diastolic blood velocity in the fetal descending aorta was documented by pulsed Doppler examinations. The right ventricular fractional shortening of these fetuses was decreased and the ratio of the right/left ventricular end-diastolic diameters was increased. The left ventricular size and myocardial contractility did not differ from normal pregnancy. These findings reveal that relative right ventricular heart dysfunction is associated with severe intrauterine distress.
Fetal blood flow measurements have a good capacity to predict unfavorable fetal outcome, especially chronic distress accompanied by IUGR. The descending thoracic aorta is of particular interest in these studies and the results reflect peripheral vascular resistance, both in the fetal placental circulation and in fetal abdominal and peripheral areas. A pathologic finding in blood velocity waveforms, especially an absent end-diastolic velocity, seems to be an early and consistent alteration that precedes the occurrence of a pathologic CTG pattern by at least several days. According to our experience, the main benefit of fetal blood flow studies is in differentiation between IUGR fetuses, in which growth retardation is accompanied by some degree of fetal hypoxia, and those cases in which the small size does not signify an immediate threat to fetal well-being. Nevertheless, there are still a number of diagnostic and practical problems. The individual fetal capability to tolerate impaired fetal placental circulation and hemodynamic redistribution is variable. Hence, it is impossible to make clinical decisions based only on hemodynamic findings; we also need diagnostic support from other methods (evaluation of fetal structures by ultrasound, CTG registration, rapid fetal karyotyping, and fetal acid-base status). In some cases, pathologic blood velocity waveforms develop as soon as at weeks 24-27, and because of the lack of reliable therapeutic methods to improve fetal condition, the selection of an ideal time of delivery is often a compromise between threatened fetal asphyxia and prematurity.(ABSTRACT TRUNCATED AT 250 WORDS)
In a case with one acardiac twin, color Doppler examination revealed retrograde umbilical circulation to this fetus. This pulsatile flow in the umbilical vessel of the acardiac fetus was supported by the cardiac function of the co-existing healthy twin.
Pulsed Doppler recordings of intracranial arterial velocity waveforms were made in 9 hydrocephalic fetuses during the second or third trimesters of pregnancy. Normal, increased, and decreased velocity waveform indices could be measured in these cases, and 1 fetus presented retrograde diastolic flow. Cerebral blood flow patterns of hydrocephalic fetuses seem to differ individually from case to case, presenting no uniform waveform type in late pregnancy. There was no obvious correlation between ventricular dilatation and the type of the velocity waveform.
608 high-risk pregnancies were monitored by repeated Doppler-examinations of the fetal aortic blood flow. An absent end-diastolic flow pattern was found to reveal fetal growth retardation with 73% sensitivity. The positive predictive value of this finding for prediction of fetal growth retardation combined with intrauterine distress (prevalence in the material 8%) was 85%. In the cases with this flow pattern, the cesarean section rate was 72%, and the mean gestational age at delivery was 34 weeks. Normal labor was not associated with any changes of umbilical arterial flow velocity waveforms, but the diastolic flow of the arcuate arteries was decreased during uterine contractions.
Relationships between human fetal aortic blood flow parameters and the corresponding echocardiographic findings were investigated in 51 normal, 26 hypertensive and 18 diabetic late pregnancies. In the normal pregnancies the time-averaged mean and peak velocities and the waveform indexes of the flow in the fetal aorta were not dependent on the cardiac size nor on the fractional shortening of the myocardium. Total blood flow in the aorta correlated well with heart size and left ventricular output. Hypertensive cases had, as a group, lower aortic velocities and higher waveform indexes than normal and diabetic pregnancies, and the difference from normal was particularly great if the fetus was growth-retarded. Myocardial contractility in these fetuses remained good in spite of these peripheric hemodynamic alterations, but the relative size of the right ventricle was increased. The diabetic cases had smaller blood flow volume in fetal aorta than in the normal cases. In contrast with normal pregnancies the myocardial fractional shortening of these fetuses decreased if the pulsatility of the aortic blood flow increased or the total blood flow in the aorta was high. These findings point to a decreased functional capacity of the fetal heart in a diabetic pregnancy, in particular in the late weeks of gestation.
The effects of danazol therapy (600 mg/day) on the liver function of 16 women with endometriosis were investigated. The primary bile acids (cholic acid [CA] and chenodeoxycholic acid [CDCA]) were analyzed with radioimmunoassays in the fasting state and after a test meal. Also, the conventional liver function tests were performed. Ultrasonography was used to detect any possible changes in the gallbladder function. The fasting concentrations of CA increased (P less than 0.05) during therapy, while those of CDCA did not change. The ratio of CA/CDCA also increased (P less than 0.001). The maximal response of CA after the test meal increased (P less than 0.01) during the trial. As regards the other liver function tests, only the transaminases significantly increased (P less than 0.01) after 1 month of therapy but showed a tendency to decrease later during the trial. The gallbladder's volume and function did not change. All the parameters studied normalized within 1 month of cessation of danazol therapy. Danazol seems to have a rather mild effect on liver function. The analyzed parameters indicate transient cell wall injury and slight disturbances in liver cell uptake and secretion mechanism and also of synthesis activity.
The outcome and complications of caesarean section were compared between 64 women who had had between three and eight previous sections (mean four) and 61 women sectioned for the first or second time. Gestational age was slightly less in the group with multiple operations. Of the women with three or more previous sections 27% had developed a fenestration in the transverse uterine scar; this was symptomless in half of them, and there was no associated severe ante- or intrapartum haemorrhage. Operation time was longer in women with multiple caesarean sections, and 13% required a caesarean hysterectomy. There were no other differences in the operative or postoperative courses between the two groups. In most women who have had multiple caesarean sections it is possible to wait for elective delivery until the fetus is mature. No absolute upper limit for the number of repeat caesarean sections can be given.
Blood flow velocity waveforms in large maternal and uterine vessels were measured longitudinally from 16 weeks gestation onwards until 12 weeks postpartum in 21 singleton pregnancies by duplex sonography. In the maternal carotid artery, time average mean velocity (TAVmean) did not show significant changes. In both the femoral artery and vein, however, significant changes were observed. In the femoral artery, TAVmean and systolic maximum velocities decreased with advancing gestation. In the femoral vein, TAVmean remained constant throughout pregnancy and was lower than postpartum. The resistance index in the uterine arteries decreased with advancing gestation and increased after delivery. Among many factors contributing to femoral arterial blood flow velocity changes in pregnancy, we suggest that a major one is the increase in uterine blood flow. Reduction in venous femoral blood flow velocity and increase in the femoral vein diameter might be associated with the common occurrence of venous disorders in pregnancy.
We present the prenatal ultrasonographic findings of an echo-dense solid mass above the normal left kidney and below the diaphragm. This mass was diagnosed as extralobar lung sequestration (ELS) at laparotomy of the child. ELS (or accessory lungs) is a rare congenital abnormality defined as a lung segment outside a normal lung, usually localized in the left lower thorax. A subdiaphragmatic localization is rare. The prognosis depends upon both the presence (as found in over 50% of reported cases) and severity of additional congenital anomalies.
Normal levels of unconjugated estriol and human placental lactogen hormone in the maternal serum and a normal, reactive pattern of non-stress test cardiotocography were recorded in a case of advanced abdominal pregnancy with surviving newborn. The placenta was inserted at the base and side walls of fossa Douglas. Fetal, umbilical and retroplacental arterial Doppler ultrasound examinations revealed normal velocity waveforms. These findings indicated that the trophoblast invasion to the retroplacental arteries also occurs when the placenta has an extra-uterine insertion, and this can result in a normal placental blood supply and function.
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Uterine arterial velocity waveforms, recorded by pulsed Doppler technology, demonstrated a significant increase in vascular resistance after the first postpartum day until the fourth to sixth postpartum week. In patients with an isthmic postcesarean hemorrhage, partial placental retention and puerperal endometritis, the corresponding waveforms presented higher diastolic velocity components than was the case for normal puerperal courses, indicating that lower uterine vascular resistance might be associated with these complications.