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Biomedical subjects

J P Tizard

Publications and source records attributed to J P Tizard.

At least 19 recordsLinked to original sources
PubMed1984

A comparison between electrical impedance and strain gauge plethysmography for the study of cerebral blood flow in the newborn.

This study investigates the possibility of using pulsatile transcephalic impedance changes, delta Z, for the continuous monitoring of cerebral blood flow, CBF, in the sick newborn infant. The performance of the impedance method is compared with the measurement of cranial flow, Fc, using a strain gauge for detecting the predicted changes in cerebral blood flow when the baby breathes 2% CO2 in air, or O2. In all five studies in which measurements were compared in air and CO2 the expected increases in Fc and delta Z were seen. In six of seven studies comparing measurements in air and O2 the expected fall in the variables was seen, indicating reduced cerebral blood flow. The problems of both these methods are discussed and we conclude that the impedance method is as good as the strain gauge method for detecting changes in cerebral blood flow.

Carbon Dioxide↗
PubMed1979

Clinical events relating to intraventricular haemorrhage in the newborn.

Continuous measurements of arterial pressures, heart rates, respiratory movements, and respiratory rates were made from birth in 44 infants at risk from intraventricular haemorrhage (IVH). 17 babies died with IVH, in 10 of whom the event was timed objectively. Events in these babies were compared with survivors of similar birthweights, gestational ages, severity of birth asphyxia, and severity of hyaline membrane disease (HMD). IVH followed severe HMD and was associated with cessation of the babies' own respiratory efforts while on a ventilator and also with characteristic cardiorespiratory events. The minimum arterial pressure before IVH was lower than in comparable babies who survived. It is suggested that fluctuations of systemic blood pressure from initial low levels may be important in the pathogenesis of IVH. It is possible that changes in cerebral blood flow are of even greater significance.

Asphyxia Neonatorum↗
PubMed1977

Timing of intraventricular haemorrhage.

The detection of the onset of intraventricular haemorrhage (IVH) during life is a necessary preliminary to understanding the cause of this condition. In 10 infants of very low birthweight treated with serial transfusions of adult blood the proportions of transfused cells circulating after each transfusion were compared with the proportion of transfused cells found in the intraventricular clot at necropsy. This allowed the timing of IVH to be restricted retrospectively to the period between consecutive blood transfusions. In addition, the proportional changes of transfused cells produced by infusion of a known red cell mass allow changes in the babies' original red cell mass to be followed during life. A fall in this value occurred in 8 infants dying with IVH and was taken to indicate haemorrhage. Comparison of the two methods in 9 infants suggested that, while in some cases intraventricular bleeding occurs rapidly, in others it takes place over a period of time. The interval between birth and the onset of haemorrhage was directly proportional to the gestational age of the infant.

Blood Transfusion↗
PubMed1975

Prognosis for infants with idiopathic respiratory distress syndrome.

Infants with the idiopathic respiratory distress syndrome admitted to the intensive care unit during January 1972 to September 1974 were reviewed. The overall mortality rate for infants whose birth weight was 1000 g or more was under 10%, and for those who established spontaneous respiration after birth it was less than 5%. The hyperoxia test was not a useful guide to prognosis. It was possible on the basis of the infants' ability to establish spontaneous ventilation after birth to divide them into two groups. In those who established adequate ventilation the mortality rate was 4-5%; in those who did not it was 57%. This test should be generally applied, since not only does it give an immediate guide to the severity of the disease, which is better than that provided by birth weight, gestational age, or the hyperoxia test, but it may be applied to infants born in and outside a hospital providing neonatal intensive care. Improvement in the outlook for infants with a bad prognosis will be achieved only by improvements in perinatal care designed to minimize severe intrapartum asphyxia in infants of low birth weight.

Birth Weight↗
PubMed1975

Very low birthweight and subsequent neurological defect (with special reference to spastic diplegia).

Of a total of 170 children who weighed 1500g or less at birth and who were born in or admitted shortly after birth to Hammersmith Hospital, London, between the years 1961-70 inclusive, 165 have been followed to ascertain the incidence of neurological handicap, with particular reference to spastic diplegia. This condition occurred in six children (3-6 per cent), all of whom were born during the 1961-64 period, an incidence in those years of 10-3 per cent, compared with 0-0 per cent in the period 1965-70 (times 2 equal to 8-72, p equal to 0-0032). These findings are considered in the context of perinatal illness and care. The one statistically significant difference found between the children with and without spastic diplegia in the earlier period was a somewhat lower mean minimum rectal temperature on the first day of life only.

Adult↗
PubMed1971

Obituaries.

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Child Psychiatry↗