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Biomedical subjects

D G Sims

Publications and source records attributed to D G Sims.

At least 19 recordsLinked to original sources
PubMed1998

Increased survival and deteriorating developmental outcome in 23 to 25 week old gestation infants, 1990-4 compared with 1984-9.

AIMS: To assess whether changes in survival over time in infants of 23 to 25 weeks of gestational age were accompanied by changes in the incidence of disability in childhood during an 11 year period. METHODS: Obstetric and neonatal variables having the strongest association with both survival to discharge from a regional neonatal medical unit and neurodevelopmental disability in 192 infants of 23 to 25 weeks of gestation, born in 1984 to 1994, were studied as a group and in two cohorts (1984 to 1989 n = 96 and 1990 to 1994 n = 96). The data collected included CRIB (clinical risk index for babies) scores and cranial ultrasound scan findings. The children were followed up at outpatient clinics. RESULTS: Between 1984 and 1989 (cohort 1) and 1990 and 1994 (cohort 2) the rate of survival to discharge increased significantly from 27% to 42% and the rate of disability in survivors increased from 38% to 68%; most of this increase was in mild disability. The proportions of survivors with cerebral palsy did not alter significantly (21% vs 18%), but more survivors with blindness due to retinopathy of prematurity (4% vs 18%), myopia (4% vs 15%) and squints (8% vs 13%) contributed to the increased rate of disability. Clinically significant cranial ultrasound findings and a high CRIB score were strongly associated with death. A high CRIB score was most strongly associated with disability. CONCLUSIONS: The rise in disability with improved survival was not due to cerebral palsy; rather the main contributors were blindness due to retinopathy, myopia, and squint. The causes of these disabilities seem to be linked to high CRIB scores. A system of regular and skilled retinal examination and access to facilities for retinal ablation should be in place in all neonatal units which undertake the care of such extremely preterm infants.

Birth Weight↗
PubMed1995

Linking visual and kinesthetic imagery in lipreading instruction.

The purpose of this study was to replicate van Uden's (1983) finding that watching oneself speak improves lipreading of visually confusable nonsense words. Specifically, this replication focused on an older group of subjects whose educational experience varied widely in the emphasis given to spoken communication. Four groups of 12 young-adult subjects who are deaf participated in evaluating two aspects of training: (a) source of video feedback (self or trainer), and (b) timing of feedback (during speech production or after speech production). Mean posttest results indicated significantly increased accuracy in identifying items that had been trained. The group that viewed self-speech after speech-production practice also demonstrated generalization to test items that were not trained. On the combined list of both trained and untrained items, both groups that viewed their own speech achieved significant gains compared to pretest scores, but those that viewed the trainer's speech did not. Response time (RT) during pre- and posttesting was measured using a computer-generated waveform display to calculate the interval between stimulus offset and response onset. Results are reported for 13 subjects with > or = 50% speech intelligibility for words in sentences. Although there were no differences attributable to training conditions, there was an overall increase in the regularity of the identification responses after training (measured by the standard deviation of RTs) and a generalization of the improvement to the untrained items. The results of this study substantiate the beneficial effects of multisensory feedback by practicing lipreading of one's own speech production. This finding appears to apply even to young-adult subjects who are deaf and whose habituated speech patterns may be quite distinct from those of talkers with normal hearing.

Adolescent↗
PubMed1995

Blood pressure, heart rate, and skin temperature in preterm infants: associations with periventricular haemorrhage.

The mean arterial blood pressure (MABP), heart rate, and skin temperature were monitored every 15 minutes in the first 10 days after birth in 34 preterm infants, gestational age 24 to 33 weeks. Ultrasound brain scans carried out daily showed that a periventricular haemorrhage (PVH) occurred in a subgroup of infants (n = 15) of lower birthweight and gestational age. In infants without PVH the daily median of MABP increased with birthweight and postnatal age; that of heart rate was not affected by postnatal age, body weight, or gestational age; and that of skin temperature showed a slight fall with postnatal age. In infants with PVH, on or before the day of PVH, daily medians of MABP and skin temperature were not significantly different from those of infants without PVH, but the daily median of heart rate tended to be slightly higher. The percentage of positive correlations between the 96 15 minute values per day for heart rate and MABP increased with postnatal age and with birthweight, but did not differ in infants who developed a PVH. The coefficient of variation (CV) of the 96 15 minute values for MABP tended to be higher in infants on the day of PVH, and a similar trend was apparent on the day before. The processes of development of blood pressure, heart rate, and skin temperature are similar in infants with or without PVH but at lower gestational ages altered blood pressure control may cause brain haemorrhage.

Birth Weight↗
PubMed1994

Use of adrenaline and atropine in neonatal resuscitation.

One hundred and five infants treated with adrenaline or atropine, or both, as part of resuscitation on 124 occasions were studied retrospectively. Adrenaline was administered to 98 infants, in 40 of whom it was in combination with atropine, and seven infants received atropine alone. Twenty infants were treated solely on the delivery unit, 81 on the neonatal medical unit, and four in both places. Twelve infants treated on the delivery unit and 13 treated on the neonatal unit survived. Follow up studies showed that 13 infants were handicapped with nine severely handicapped. Extreme prematurity, the need for early or repeated resuscitation using these drugs, particularly for episodes of collapse without a clear precipitating cause, and asystole rather than bradycardia were associated with a worse outcome. Evidence is accumulating to support a view that the use of these drugs for resuscitation at birth and in the first week of life of extremely preterm infants may be inappropriate.

Atropine↗
PubMed1993

Measurement of ionised calcium concentration in neonates.

Whole blood ionised calcium concentration was measured simultaneously in capillary and arterial blood from neonates being nursed on an intensive care unit using an ion selective electrode. The mean arterio-capillary difference was -0.027 mmol/l (95% confidence intervals -0.041 to -0.012 mmol/l) and the limits of agreement between the two measurements were 0.034 and -0.088 mmol/l. Measurement of ionised calcium in capillary blood is acceptable for clinical purposes.

Arteries↗
PubMed1992

Skin temperature and heart rate rhythms in infants of extreme prematurity.

Nine preterm infants of 26 to 29 weeks' gestational age and 792 to 1200 g birth weight spent six to 17 weeks in our neonatal medical unit. Hourly recordings of skin temperature and heart rate were carried out. The first five to 15 weeks were spent in the intensive care ward, in continuous light, due to various medical conditions. After recovery they were moved to a nursery for one to nine weeks, with 12 hourly periods of light and darkness. Four infants developed circadian rhythms in temperature and three in heart rate in light-dark periods, the remainder failing to do so. Some infants take longer than others to develop circadian rhythms but the reasons for this are not clear. It is suggested that earlier exposure to a light-dark environment may synchronize the 'body clock' to a 24 hour period in more preterm infants.

Circadian Rhythm↗
PubMed1991

Family implications of neonatal Gorlin's syndrome.

Two very preterm infants (born at 29 and 25 weeks, respectively) were found to have abnormal ribs. Though this was thought unimportant at the time, it was subsequently shown to indicate that some members of their families had a dominantly inherited risk of developing skin cancer and other serious problems.

Adult↗
PubMed1991

Gastrointestinal blood flow velocity after the first feed.

Twenty preterm infants (gestational age range 27-36 weeks) who had never been fed enterally were studied. Doppler indices of flow velocity from the superior mesenteric and coeliac arteries were measured immediately before, and at postprandial time intervals up to 60 minutes after, a first feed of 1 ml of milk given through a nasogastric tube. There were no significant differences between the preprandial and postprandial values of blood pressure, heart rate, oxygen and carbon dioxide tensions, and pH. The median peak systolic velocity (PSV) (55.9 cm/sec) and time average mean velocity (TAV) (10.6 cm/sec) before the feed at the superior mesenteric artery rose progressively and significantly to postprandial peaks of 88.5 cm/sec and 20.5 cm/sec at 45 minutes, respectively. Significant postprandial rises in the median PSV and TAV values at the coeliac artery were also observed, with a peak at 45 minutes. There were no significant correlations between blood flow velocity indices (preprandial or postprandial) and gestational age, postnatal age, conceptional age, or birth weight. We conclude that the first exposure of preterm babies to a small volume of milk feed is associated with postprandial changes in blood flow velocity consistent with an increase in blood flow in the superior mesenteric and coeliac arteries, although the mechanism of this response is uncertain.

Blood Flow Velocity↗
PubMed1990

Developmental delay in congenital myotonic dystrophy after neonatal intensive care.

Six infants with congenital myotonic dystrophy survived after neonatal intensive care. In later childhood they were assessed by the Griffiths Mental Development Scales: five children were functioning in the mildly handicapped to borderline range of development (DQ 64.0 to 79.0) and the remaining child was severely delayed in development (DQ 33.0). The five children with higher DQ values had a history of ventilatory support of 30 days or less after birth. By contrast, the remaining child with the lowest DQ value had been ventilated for 43 days. This study provides further evidence that prolonged ventilation after birth has prognostic significance in identifying severely affected cases with congenital myotonic dystrophy.

Child, Preschool↗
PubMed1988

Treatment of renal failure in neonates.

Thirty neonates with acute renal failure were studied, 27 of whom died (90%) including nine of 12 treated by peritoneal dialysis. Three main aetiological groups were identified. Septicaemia was a principal cause of late onset acute renal failure, with an incidence equal to that of serious perinatal disorders. It is recommended that tolazoline should be used with caution in the treatment of hyperkalaemia as it may have a role in the aetiology of acute renal failure, the incidence of which is increasing.

Acidosis↗
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↗
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

Visual evoked-response components related to speechreading and spatial skills in hearing and hearing-impaired adults.

Averaged visual evoked responses (VER) to light flashes which varied systematically in brightness and predictability were collected from 24 hearing and 24 hearing-impaired adults. In addition, speechreading, abstract reasoning, and spatial relations tests were administered. Separate principal components analyses of the VERs were conducted on each group to replicate and extend our previous report of an early VER component (VF16) which reflected individual differences in the speechreading skills of hearing subjects. VF16 appeared in both analyses, confirming its replicability as a latent VER component. VF16 correlated with speechreading skill in hearing-impaired males (r = -.73), under stimulus conditions identical to those in our previous study. However, its correlations with speechreading skills in hearing subjects were not significant. VF16 also varied systematically with stimulus predictability and correlated with spatial ability in both groups only when the time of occurrence of the light flashes was predictable. These data tentatively suggest that VF16 is a VER correlate of individual differences in a psychologically dynamic process, perhaps involving expectancy, which may relate to the performance of hearing-impaired and hearing people in visually based communication or cognitive processing situations.

Adult↗
PubMed1983

Protective effect of vitamin E (DL-alpha-tocopherol) against intraventricular haemorrhage in premature babies.

Forty four babies, of less than 32 weeks' gestation, were either randomly given 25 mg/kg vitamin E (DL-alpha-tocopherol acetate) intramuscularly after birth (day 0) and on days 1, 2, and 3 or served as controls. Frequent real time ultrasound examinations of the brain were made in each baby during the first week and less frequently thereafter. In babies under 32 weeks' gestation the incidence of intraventricular haemorrhage was lower in supplemented babies (18.8%) compared with the controls (56.3%). On days 0, 1, 2, and 3 median plasma vitamin E concentrations in babies without haemorrhage and in those with subependymal haemorrhage only were similar. Babies with intraventricular haemorrhage had lower median concentrations on day 1 (p less than 0.002) and day 2 (p less than 0.05) compared with those with subependymal haemorrhage and lower concentrations on day 0 (p less than 0.02) and day 1 (p less than 0.05) compared with those without haemorrhage. These findings suggest that in premature babies vitamin E, an antioxidant, protects endothelial cell membranes from oxidative damage and disruption and limits the magnitude of haemorrhage and its spread from the subependyma into the ventricles.

Cerebral Hemorrhage↗