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Biomedical subjects

M L Chiswick

Publications and source records attributed to M L Chiswick.

At least 37 records · Page 2Linked to original sources
PubMed1990

Ischaemic brain lesions diagnosed at birth in preterm infants: clinical events and developmental outcome.

In 232 newborn babies of less than 32 weeks' gestational age ultrasound brain scans were carried out shortly after birth, daily for the first week of life, and at least twice weekly thereafter. Periventricular echogenicity associated with or progressing to periventricular leukomalacia (ischaemic brain lesions) was present in nine babies within two hours of birth (early onset); 30 other babies subsequently developed similar lesions (late onset). Babies with early onset lesions were more likely to have a history of intrauterine growth retardation and to have recurrent apnoea in the first few hours after birth. By contrast, late onset lesions were associated with hyaline membrane disease. In later childhood four of six survivors with early onset periventricular leukomalacia, and seven of 14 survivors with late onset periventricular leukomalacia, had various disabilities including spastic diplegia, impaired vision, squints, sensorineural hearing loss, and developmental delay. In a third of the children with disabilities ischaemic brain lesions were noted within two hours of birth, raising the possibility that some of this damage had taken place before or during birth.

Brain↗
PubMed1990

Skin conductance and arousal in the newborn.

We measured skin conductance continuously from the sole of a foot in babies of different conceptional ages before, during, and for 10 minutes after a 'heel prick' carried out for routine blood sampling. We studied 82 healthy babies whose gestational and postnatal ages ranged from 25-42 weeks, and 1-73 days. The median skin conductance level (preheel prick) in babies of 40-43 weeks' conceptional age was 0.6 microS (microsiemens) and differed significantly between awake babies (1.2 microS) and those who were asleep (0.5 microS). In contrast babies less than 40 weeks had a significantly lower median skin conductive level (0.3 microS) which was identical in awake and asleep babies. In response to the heel prick all babies became aroused and skin conductance rose sharply and immediately in 21 out of 22 (95%) babies 40-43 weeks' conceptional age, and in seven out of 23 (30%) babies 36-39 weeks. The median rise at one minute in babies of 40-43 weeks was significantly higher than those 36-39 weeks (2.7 microS compared with 0.5 microS). No babies less than 36 weeks had a change in their skin conductance after the heel prick. These results are consistent with the notion that 'emotional sweating' is a function of maturity and does not develop until 36 weeks' conceptional age.

Arousal↗
PubMed1988

Clinical factors associated with adverse outcome for babies weighing 2000 g or less at birth.

Using clinical factors, the probabilities of survival with and without major handicap were separately calculated by multiple logistic regression for 988 children who weighed 2000 g or less at birth and who were born in the period 1976-1980. For survivors weighing 501-1250 g in whom incidence of serious handicap was 21%, neonatal fits and the need for mechanical ventilation carried significantly increased risks of later serious handicaps. In contrast, for survivors weighing 1251-2000 g in whom the incidence of serious handicap was 6%, significant factors were spontaneous, uncomplicated preterm delivery, recurrent apnoea, and abnormal neonatal neurological findings. The probability of dying was assessed in two ways--firstly, using seven clinical factors available on admission to the neonatal unit, and secondly, using 10 perinatal and neonatal factors. Handicapped survivors had a perinatal risk between that of those babies who survived and that of those who died. Of the handicapped survivors, those with spastic diplegia and hemiplegia had been extremely low risk babies (medians 1.4% and 1.6%, respectively), whereas those with other impairments had much higher risks (range 17.5-38.1%). We postulate that certain impairments arise independently of clinical events, although most occur in children who had complicated perinatal courses.

Developmental Disabilities↗
PubMed1988

Referrals to a regional neonatal intensive care unit.

Over a three year period 444 requests for the neonatal transfer of babies with acute medical problems were received at this regional neonatal medical unit. Despite an increase in available resources in the North Western Health Region the provision of intensive care remained inadequate with 38% of requests declined, and babies had to be referred elsewhere including to neighbouring health regions. The survival of those babies who had to remain at the hospital of birth (49%) was significantly lower than for those transferred to the regional centre (71%). Those babies declined admission had significantly lower gestational ages and birth weights than those accepted. For those babies with respiratory failure and birth weights of less than 1500 g within these two groups, however, there were no significant differences in birth weight, gestational age, or gender yet survival was significantly better for those transferred. Babies from multiple pregnancies caused particular problems if neonatal transfer was required.

Birth Weight↗
PubMed1988

Neurodevelopmental outcome of babies weighing less than 2001 g at birth: influence of perinatal transfer and mechanical ventilation.

From 1976 to 1980, 1034 children who had weighed less than 2001 g at birth were cared for at the North Western regional neonatal intensive care unit. Of these, 315 babies were neonatal referrals and 91 were born in the unit after antenatal transfer from their district hospital. Significantly fewer of the babies referred as neonates survived (n = 167, 53%) compared with 67 of the antenatal referrals (74%), and 490 of those born in the unit (78%). They also had a higher incidence of major handicaps (24 of 167, 14%) compared with six of 67 (9%) of the antenatal referrals and 35 of 490 (7%) of those born in the unit. To control for selection bias among neonatal referrals, the outcome of ventilated neonatal referrals was compared with that of ventilated babies born in the unit. The two groups were comparable for the incidence of a wide range of neonatal complications. No differences in rates of survival or handicap were found. We conclude that sick babies transferred after birth to regional neonatal intensive care units have similar short and long term outcomes to sick babies born in regional units.

Blindness↗
PubMed1987

Neurodevelopmental outcome in babies weighing less than 2001 g at birth.

From 1976 to 1980, 1034 infants with birth weights of 500-2000 g were cared for in the neonatal medical unit; 724 were discharged. Twenty (2.8%) subsequently died and 654 (90.3%) were followed up at a median age of 3 years 3 months. Fifty five (7.6%) survivors had major neurodevelopmental handicaps not attributable to congenital anomalies. Increasing prevalence of major handicap was found with decreasing birth weight and gestation. Children with birth weights of less than 1251 g had a higher incidence of all major disabilities. Handicapped children with a birth weight less than 1251 g were more likely to have blindness, deafness, multiple disabilities, and more severe cerebral palsy. There were 146 (20.2%) children with minor disabilities: neurological impairments (n = 11), borderline results on psychometric testing (n = 18), visual impairments (n = 52), hearing impairments (n = 40), and speech impairments (n = 71). Children weighing less than 1251 g at birth had a higher incidence of minor visual and hearing impairments. In 389 children the mean Griffiths quotient was 101.6 (SD 17.2) (range 50-147), and 158 children had a mean Wechsler preschool and primary intelligence quotient of 101.8 (13.2) (range 56-127): these quotients did not vary with birth weight or gestation but did vary with socioeconomic group, schooling, and family structure. During the study period an improving prognosis in terms of both survival and handicap was observed in children weighing less than 1251 g at birth.

Blindness↗
PubMed1986

Head size, brain growth, and lateral ventricles in very low birthweight infants.

Ninety eight newborn infants weighing less than 1500 g at birth and with gestational ages from 26 to 32 weeks were followed prospectively. They were grouped according to real time ultrasound scans in the neonatal period: infants in group A (n = 20) had periventricular haemorrhage (PVH) and normal ventricles; infants in group B (n = 26) had PVH and dilated ventricles (none with clinical hydrocephalus); and infants in group C, who formed the control group (n = 52), had no PVH and normal ventricles. At outpatient follow up a static image ultrasound scanner was used to measure the width of the lateral ventricles and brain hemispheres. The three groups of infants showed similar growth in occipitofrontal circumference, biparietal diameter, and brain hemispheres irrespective of a history of PVH or ventricular dilatation. The relation of ventricle size to biparietal diameter was similar in those infants in groups A (PVH alone) and C (controls) who had a good outcome. About a third (n = 8) of the infants in group B had persistent ventricular dilatation in relation to biparietal diameter and a poor outcome associated with developmental delay and cerebral palsy. By contrast, the remaining two thirds (n = 18) of the infants in group B who later had smaller ventricles in relation to biparietal diameter showed fewer neurodevelopmental sequelae. It is suggested that persistent ventricular dilatation in relation to biparietal diameter at follow up carries a bad prognosis, which might be due to brain atrophy.

Brain↗
PubMed1985

Relation between periventricular haemorrhage and ischaemic brain lesions diagnosed by ultrasound in very pre-term infants.

Ultrasound brain scans were carried out serially during the first month of life on 219 newborn infants of 32 weeks' gestation or less. Periventricular haemorrhage (PVH) alone was observed in 36.1% and ischaemic lesions in 17.8%. By comparison with PVH, ischaemic lesions evolved later (median 7 days vs 2 days), and were associated with a significantly higher frequency of persistent ventricular enlargement and increased mortality. Birth asphyxia, antepartum haemorrhage, recurrent apnoea, and septicaemia--events which are known to promote systemic hypotension--were all strongly associated with ischaemic lesions but not with PVH alone.

Brain Ischemia↗
PubMed1985

Feeding, growth, and biochemical studies in very low birthweight infants.

Fifty infants of gestational age 28 to 32 weeks and birthweight less than 1501 g were reviewed on the expected date of delivery and at conceptional ages of 4, 8, and 12 months. All infants were at home by the expected delivery date, were fed on demand, and weighed regularly. On the expected delivery date and at 4 months, the amounts of formula milk and weaning food accepted were recorded; energy and protein intakes were calculated; and serum sodium, potassium, urea, protein, and osmolality were measured. The birthweight of these infants ranged between the 3rd and 75th centiles (on average about the 20th) but at the expected delivery date was, on average, below the 3rd centile. Infants who had been weaned in the first 4 months after the expected delivery date (n = 26) had similar energy and protein intakes and similar biochemical indices to those weaned later (n = 24). They achieved catch up growth (below 3rd to 10-25th centile) by 1 year, irrespective of the time of weaning and without any differences in metabolic 'stress'.

Blood Proteins↗
PubMed1984

Non-specificity of surfactant deficiency in neonatal respiratory disorders.

The phospholipid content of lung fluid taken from 77 babies during the first day of life was studied. Babies with hyaline membrane disease had low concentrations of the surfactant phospholipids phosphatidylcholine, phosphatidylinositol, and phosphatidylglycerol. The palmitic acid content in phosphatidylcholine was also lower than normal. Surfactant deficiency was not, however, specific for hyaline membrane disease, as similar phospholipid abnormalities were observed in babies with congenital pneumonia and transient tachypnoea of the newborn. These findings have important clinical implications. They are relevant to research into surfactant substitution and cast doubts on the value of the antenatal phospholipid lung profile of amniotic fluid in predicting the risk of hyaline membrane disease.

Gestational Age↗