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Biomedical subjects

A R Wilkinson

Publications and source records attributed to A R Wilkinson.

At least 73 records · Page 4Linked to original sources
PubMed1988

Quantification of changes in normal neonatal EEGs with gestation from continuous five-day recordings.

To quantify changes in the pattern of the electroencephalogram (EEG) in relation to gestational age, a continuous two-channel record of the EEG with electrocardiogram (ECG) and respiration was made for the first five days after birth. 25 healthy babies with gestational ages of 26 to 42 weeks were studied. All were developmentally normal when assessed at 18 months. The EEG was divided into two distinct patterns; trace-alternant activity and continuous activity. The duration of trace-alternant activity and the mean duration of each epoch of trace-alternant activity decreased with increasing gestational age. Epochs of continuous activity increased in duration with increasing gestational age. Within epochs of trace-alternant activity the duration of each burst was independent of gestational age, but the mean inter-burst interval and the maximum voltage of slow-wave decreased with increasing gestational age. Analysis of variance showed all changes in relation to gestational age to be significant.

Brain↗
PubMed1988

Factors influencing colonisation with gentamicin resistant gram negative organisms in the neonatal unit.

The proportion of babies colonised with gentamicin resistant Gram negative organisms in a nursery over a 30 month period did not correlate with the quantity or duration of aminoglycosides used, but it did correlate with two indicators of workload: the number of baby days and a score based on the level of nursing care required. Spread of resistant organisms may be more likely as workload increases.

Bacterial Infections↗
PubMed1988

Cerebral electrical impedance: do indices derived from it provide information on cerebral blood flow in the neonate?

Cerebral electrical impedance was compared with simultaneous estimations of cerebral blood flow (CBF infinity) using the 133Xe clearance technique on 28 occasions in 9 neonates who had changes in PaCO2 and hence presumably cerebral blood flow between measurements. Various indices derived from the impedance waveform which have been reported in the adult to correlate with blood flow were analysed for their relationship with CBF infinity. Percentage change of the two variables was calculated and three indices showed a significant correlation using linear regression. They were peak amplitude (delta Zp), delta Zp times heart rate (delta Zp x HR), and backslope projection. The regression equation for the index with the closest correlation was delta Zp x HR = 0.57CBF infinity + 3.4 with r = 0.68 (p = 0.003) and standard error of the estimate = 29%. Some cerebral electrical impedance indices did correlate with cerebral blood flow changes under the conditions of this study and provide accurate information on the direction of changes but because of the wide confidence limits cannot be used for quantification of cerebral blood flow changes.

Blood Gas Monitoring, Transcutaneous↗
PubMed1988

Effects of transcutaneous scopolamine and depth on diver performance.

Transdermal scopolamine is an effective anti-motion-sickness medication that has less CNS side effects at normal ambient pressure than orally ingested agents. To see whether it has an effect on performance at depth, 24 healthy sport divers were exposed to depths equivalent to 5 m (1.5 ATA) and 36 m (4.8 ATA) in a dry recompression chamber, breathing air and wearing a skin patch containing either scopolamine or inactive placebo. Patches and dive depths were presented in a counterbalanced, double-blind experimental design. Tests of sentence comprehension, simple arithmetic, and manual dexterity were used to evaluate psychometric and cognitive performance. Drug side effects were recorded. The Bennett Hand Tool Dexterity Test was evaluated for its suitability for repeated measures testing, and found to be robust. Manual dexterity and sentence comprehension were significantly impaired at depth whereas arithmetic skills were not. No significant effects on diver performance from transdermal scopolamine were seen. Certain side effects such as blurred vision were more common with scopolamine than with placebo. The use of transdermal scopolamine as an antiemetic during diving operations deserves field evaluation.

Administration, Cutaneous↗
PubMed1987

Surveillance of colonization and late-onset septicaemia in neonates.

Twenty-seven newborns had an episode of late-onset sepsis (septicaemia or bacterial meningitis after 48 h of age) over an 18 month period. Preceding or simultaneous surface cultures were available from 26 babies. Colonization with the organism causing sepsis could only be documented in 10 cases. Colonization with aminoglycoside-resistant Gram negative organisms was common but there were only two cases of systemic sepsis with a resistant organism. Pseudomonas aeruginosa frequently colonized babies over the first 8 months of the survey, but subsequently virtually ceased to colonize babies, although it continued to be a common cause of late-onset sepsis. These findings do not support the utility of routine surveillance of organisms colonizing neonates in predicting bacteria causing late-onset sepsis. They also cast doubt on the value of eliminating colonizing organisms by expensive infection control measures.

Bacteria↗
PubMed1987

New birthweight and head circumference centiles for gestational ages 24 to 42 weeks.

Based on 20,713 singleton livebirths at the John Radcliffe Hospital, Oxford, in 1978-1984, we calculated new birthweight and head circumference values for males and females between 24 and 42 weeks of gestation. Among the 803 babies born at or before 34 weeks of gestation, 28% were delivered electively for fetal problems; they were considerably lighter and had smaller heads than infants born after spontaneous preterm labour. As we and others have recommended elsewhere, the electively delivered preterm infants were excluded from the calculation of the new birthweight and head circumference centiles. In our series males were heavier and had larger head circumferences than females at most gestational ages. There were consistent and statistically significant differences in birthweight at all gestational ages from 37 weeks and in head circumference at all gestational ages from 35 weeks.

Birth Weight↗
PubMed1987

Serum acute phase reactants in necrotizing enterocolitis.

The serum acute phase reactants, C-reactive protein (CRP) and orosomucoid, rose significantly within 24 to 48 hours of presentation in infants with definite necrotizing enterocolitis (NEC) compared with the levels in infants with symptoms who tolerated early reintroduction of enteral feeds. A serum CRP value greater than 10 mg/l within 48 hours identified infants with definite NEC with a 92% sensitivity and an 81% specificity. Serum CRP values remained elevated at 7 to 10 days in 4 infants with late septicaemia and in 4 of 5 infants with abscess or early stricture requiring surgery. Serum acute phase reactants are a potentially valuable adjunct to clinical assessment in the management of infants with suspected NEC.

Acute-Phase Proteins↗
PubMed1987

Influence of elective preterm delivery on birthweight and head circumference standards.

We calculated new birthweight and head circumference centiles for boys and girls between 24 and 42 weeks' gestation from 20,713 singleton live births at our hospital between 1978 and 1984. Among the 803 babies born at or before 34 weeks' gestation, 28% were delivered electively for fetal problems; they were considerably lighter than babies born after spontaneous preterm labour. In contrast, they showed only a small deficit in head circumference, possibly due to a brain sparing effect in growth retarded infants. Electively delivered preterm infants cause a bias in birthweight and head circumference centiles and we recommend that these babies should be excluded when these centiles are calculated.

Birth Weight↗
PubMed1987

New fontanometer for continuous estimation of intracranial pressure in the newborn.

Intracranial pressure was estimated by a new pneumatic applanation fontanometer in babies in intensive care. A close correlation with cerebrospinal fluid pressure was found on 35 separate occasions. In 12 control babies the mean (SD) fontanelle pressure was 5.2 (2.2) cm H2O, in eight with a hypoxic-ischaemic encephalopathy it was 12.6 (4.3) cm H2O, and in nine with post-haemorrhagic hydrocephalus it was 10.8 (4.3) cm H2O. In four babies monitored continuously over seven days the correlation remained good. The fontanometer enables pressure to be monitored accurately, continuously, and non-invasively in neonates at risk of raised intracranial pressure.

Brain Diseases↗
PubMed1987

Duration of antibiotic courses for neonates.

A survey of the use of antibiotics in a neonatal unit for two years showed a considerable reduction in the mean duration of courses prescribed without any appreciable change in morbidity.

Anti-Bacterial Agents↗
PubMed1986

Evidence of inadequate humidification of inspired gas during artificial ventilation of newborn babies in the British Isles.

Data on routine humidifier settings used in respiratory support for newborn babies were obtained from 242 neonatal units in the British Isles. For each of the most commonly used humidifiers inspired gas humidity was measured under routine clinical conditions with an electronic hygrometer. Most endotracheally intubated babies breathe inspired gas of well below physiological humidity (44 mg H2O/l) and many below the minimum recommended for adults by the British Standards Institution (33 mg H2O/l). Inadequate humidification could contribute to several complications of artificial ventilation in newborn babies by inhibiting mucociliary clearance.

Aged↗
PubMed1986

Thiopentone induced coma after severe birth asphyxia.

The aim of this study was to determine the feasibility of inducing a prolonged coma in severely asphyxiated newborn babies by the infusion of high dose thiopentone. In six severely asphyxiated babies the electroencephalograph (EEG) and blood pressure were monitored continuously. Thiopentone was infused at a rate sufficient to suppress completely the EEG providing the mean blood pressure remained above 35 mm Hg; it was continued until there was no evidence of cerebral oedema for 24 hours. In two the infusion was stopped prematurely because of hypotension that was unresponsive to treatment. In the other four a deep coma was maintained for a median duration of 127 hours. All developed pharmacodynamic tolerance to the thiopentone and showed non-linear elimination kinetics. Three babies died; the three survivors have moderate to severe handicap. It was concluded that with full intensive care it is possible to induce a deep coma; the outcome does not seem to be improved, however, and the incidence of complications was high.

Asphyxia Neonatorum↗
PubMed1986

Inadequate humidification of respiratory gases during mechanical ventilation of the newborn.

Proximal airway humidity was measured during mechanical ventilation in 14 infants using an electronic hygrometer. Values below recommended minimum humidity of adult inspired gas were recorded on 251 of 396 occasions. Inadequate humidification, largely due to inadequate proximal airway temperature, is commoner than recognised in infants receiving mechanical ventilation.

Humans↗
PubMed1986

Prolonged positive airway pressure for severe neonatal tracheobronchomalacia.

A very low birthweight preterm baby with respiratory distress at birth was found to have severe congenital tracheobronchomalacia. Continuous positive airway pressure was given through an endotracheal tube without tracheostomy for 15 weeks before unassisted respiration could be maintained. Diagnosis was made and progress monitored by laryngobronchoscopy on three occasions.

Bronchial Diseases↗
PubMed1985

Perinatal events which precede periventricular haemorrhage and leukomalacia in the newborn.

Ultrasound brain scans were obtained daily for the first 5 days after birth, on day 7 and then weekly until discharge from hospital in 86 babies during a 12-month period. The babies weighed less than 1501 g or were less than 34 weeks gestational age. Fifty-one (59%) had normal scans, 34 (40%) developed periventricular haemorrhage, and seven (8%) developed periventricular cysts (associated with periventricular haemorrhage in six). Factors associated with periventricular haemorrhage were perinatal hypoxia, acidosis, hypercapnia and hypoxia after birth. Babies who developed periventricular cysts (periventricular leukomalacia) were more likely to have been hypoxic at birth and in four of the seven there had been a maternal antepartum haemorrhage. The association of perinatal hypoxia with periventricular haemorrhage and leukomalacia suggests that intrapartum events may predispose to the onset of these lesions which then develop postnatally. Prevention of perinatal hypoxia may play an important role in diminishing the disability caused by these conditions.

Brain Diseases↗