The effect of amniocentesis and drainage of amniotic fluid on lung development in Macaca fascicularis.

Amniocentesis and withdrawal of amniotic fluid was performed on pregnant monkeys (Macaca fascicularis) at two stages in development, either between 47 and 64, or between 85 and 95 days gestation. After birth the lungs of each infant monkey were studied using precise morphometric techniques, and compared with those in a control group of animals. The lungs after amniocentesis had alveoli of normal maturity but reduced in number and increased in size, features which both reduce the relative area for gas exchange. There was also a reduction in the number of respiratory airways. These changes occurred regardless of the time of amniocentesis, the amount of fluid removed and even if the membranes were simply punctured with no fluid removal. There is some evidence to suggest that similar sublethal effects may be present in human infants after maternal amniocentesis.

Accuracy of imaging of the brains of newborn infants by linear-array real-time ultrasound.

Comparisons were made in 69 newborn infants of the appearance of the brain as visualised by linear-array real-time ultrasound, computerised tomography and at autopsy, in order to evaluate the accuracy of ultrasound for the detection of lesions in the brain. Ultrasound was found to give a good estimate of the presence and extent of haemorrhage into the germinal layer and ventricles, and also to be very useful for assessing the appearance of the ventricular system. Ultrasound diagnosed extradural haemorrhages but was unhelpful for identifying subarachnoid haemorrhages or lesions in the posterior fossa.

Pneumothorax and cerebral haemorrhage in preterm infants.

Real-time ultrasound was used to examine the brains of all 95 infants born at less than 33 weeks of gestation who were admitted to the neonatal unit of University College Hospital in 1979. Evidence was obtained which strongly suggested that pneumothorax causes and aggravates haemorrhage into the germinal layer and ventricles of preterm infants.

Placental localization by liquid crystal thermography.

The accuracy of determining placentation by using plates of cholesteric thermocrystals has been studied, with the actual placental site being defined as that shown by ultrasound B scanning. In our study, 43 patients were examined, including eight with placenta previa. Although all eight cases of placenta previa were identified, there were three false-positive test results. It is believed that suitable modification of the composition of the liquid crystal mixture will improve the accuracy of this simple technique, which would be valuable in areas where sophisticated equipment is not yet available.

Ultrasound detection of brain damage in preterm infants.

A linear-array real-time ultrasound scanner with a 5 MHz probe was used to examine the brains of 31 infants born at less than 33 weeks of gestation. The equipment was mounted on a small trolley and the infants could easily be scanned in their incubators. 7 of the 31 infants were shown to have cerebral lesions, including haemorrhages into the germinal layer and ventricles, hydrocephalus, and infarction of the periventricular region and cerebral cortex. The type and extent of the lesions were conformed by computerised tomography and at necropsy. Ultrasound scanning is a safe, simple, non-invasive technique that provides valuable information for the diagnosis, investigation, and treatment of lesions in the brains of newborn infants.

The value of a scoring system in predicting outcome of pre-term labour and comparing the efficacy of treatment with aminophylline and salbutamol.

A simple score, derived by allocating points to a selection of factors which influence the outcome of pre-term labour, was found to relate to the success of treatment. Used as a measure of the situation before therapy, this score can define a baseline allowing a realistic comparison of therapeutic methods. In this series, despite treatment, a large number of patients still were delivered before term and within a few days of admission to hospital. Thus it would seem that although drugs suppress uterine activity, they cannot neutralize the adverse effects of other factors associated with pre-term labour.

The relevance of antenatal and intrapartum fetal heart rate patterns to fetal outcome.

Antenatal fetal heart rate (FHR) as an indicator of fetal status was evaluated in two separate studies. The first attempted to determine, in 30 minutes of continuous recording from each of 50 antenatal patients, relationships between spontaneous FHR changes and fetal condition before and after birth. No significant association was found between observed FHR patterns and antenatal or neonatal fetal status. The second study used induction of labour as a stress test, because similar conditions to that required for oxytocin stress testing were present and there was the advantage of direct FHR recording. In 150 induced and monitored labours, FHR changes associated with the first six suitable contractions seldom related to Apgar scores at birth or development of fetal distress in active labour. Fetuses showing no response to contractions tended to have better Apgar scores than those which showed FHR decelerations. Results from these studies do not substantiate reports that FHR changes arising spontaneously, or in response to induced contractions, reflect satisfactorily the existing or subsequent fetal status.

Ultrasound and amoebic liver abscess.

Eight of 12 patients referred to an ultrasound clinic were eventually found to have a liver abscess. All 8 abscesses were confirmed positively by ultrasonic examination. Using ultrasound, an amoebic abscess can be accurately located within the liver and the optimal site for needling suggested to the clinician. Ultrasound is an accurate, non-invasive, diagnostic aid in this condition.

Ultrasound and jaundice.

We have examined 26 consecutive jaundiced patients referred to the ultrasound clinic. A differentiation between extrahepatic and other causes of jaundice was possible in 23 of the 24 patients satisfactorily examined. The use of ultrasonic techniques in the jaundiced patient offers a high degree of accuracy to the clinician, and little or no discomfort to the patient.

Ultrasound and abdominal hydatid disease.

Twenty-two hydatid cysts have been accurately located in the abdomens of seven patients by ultrasound B-scanning. Lapartomy has confirmed the presence of 19 of these cysts. Grey-scale techniques do not appear to add appreciably to the ease of diagnosis in this condition. Ultrasound can give the clinician a good idea of the extent of the disease process and has the advantage of being completely non-invasive.

Progression in response patterns of fetal heart rate throughout labour.

A study of 70 fetal heart rate (FHR) traces throughout labour has allowed analysis of FHR responses associated with approximately 7000 individual uterine contractions. The significance of the less emphasized FHR patterns has been assessed and an attempt has been made to identify any trend or progression in the occurrence of these patterns. Transient acceleration was the most frequently occurring response in early labour and was the first observed response in the majority of cases. Decelerations became prevalent as labour progressed. A hypothesis is proposed to explain the observed overall progression in FHR responses and the possible physiological mechanisms underlying the cyclic changes in response patterns which occur throughout the course of labour.

The analysis of continuous fetal heart rate traces in the first and second stages of labour.

In the search for a simplified method of fetal heart rate trace assessment 50 traces recorded during the first stage of labour and those recorded in the last hour of each of a further 50 labours have been analysed intensively. The importance of baseline variability in predicting possible fetal distress in both the first stage and the last hour of labour is shown and the possible use of an objective measurement of baseline variability in the further screening for fetal acidosis is described. The importance of lag time measurement in the first stage of labour is demonstrated and the relationships between fetal scalp blood pH and other heart rate parameters is discussed. Significant inverse correlations between one-minute Apgar score and maximum amplitude of deceleration and total deceleration area in the last hour of labour are also shown. Temporal relationships between intrauterine pressure rises and transient changes of fetal heart rate failed to give significant correlations in the last hour. These findings in the last hour of labour are compared with those obtained in the first stage of labour and the differences are discussed.

Ultrasonic "B" scanning as a pregnancy test after less than six weeks amenorrhoea.

Sixty patients with less than six weeks amenorrhoea were examined by ultrasonic "B" scanning for the detection of pregnancy. The results were compared with those obtained by histological examination of the aspirate after the patient had undergone menstrual regulation by vacuum aspiration of the uterine contents. The overall accuracy was 79 per cent with 15 per cent false positives. The accuracy after 39 days amenorrhoea was 95 per cent. The technique was compared with an immunological pregnancy test.