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Biomedical subjects

A T Gibson

Publications and source records attributed to A T Gibson.

At least 19 recordsLinked to original sources
PubMed2006

Pinching, electrocution, ravens' beaks, and positive pressure ventilation: a brief history of neonatal resuscitation.

Since ancient times many different methods have been used to revive newborns. Although subject to the vagaries of fashion for 2000 years, artificial respiration has been accepted as the mainstay of neonatal resuscitation for about the last 40. Formal teaching programmes have evolved over the last 20 years. The last 10 years have seen international collaboration, which has resulted in careful evaluation of the available evidence and publication of recommendations for clinical practice. There is, however, little evidence to support current recommendations, which are largely based on expert opinion. The challenge for neonatologists today is to gather robust evidence to support or refute these recommendations, thereby refining this common and important intervention.

Asphyxia Neonatorum↗
PubMed2005

Parenting the premature infant: balancing vulnerability and quality of life.

BACKGROUND: Relationships between child quality of life (QOL), maternal well-being and parenting were explored in a questionnaire study. METHOD: Mothers of 126 full-term (FT) and 91 pre-term (PT) infants during the child's second year of life completed measures of their own and the child's quality of life and behavioural difficulties. We developed a measure of parenting style derived from Regulatory Focus Theory (RFT), to distinguish greater reported use of promotion as opposed to prevention strategies (emphasising gains rather than losses, and encouraging pursuit of goals rather than prevention of harm). RESULTS: The two groups of mothers showed no differences on the parenting measure, but those in the PT compared with the FT group described their infant as having lower QOL and more behavioural and mood problems, and rated their own well-being as less satisfactory. Greater use of promotion was associated with reports of fewer difficulties (better QOL) for the child and better mothers' well-being. Differences in mothers' well-being as a function of group (FT vs. PT) and promotion were strongly mediated by mothers' perceptions of their child's difficulties. At the same time, associations with child difficulties were partly mediated by mothers' well-being, suggesting that maternal distress may have partly contributed to higher perceptions of such difficulties. Among PT infants, the degree of prematurity predicted child difficulties, but was not consistently related to mothers' well-being. DISCUSSION: Mothers of PT infants report more physical health and behavioural difficulties than mothers of FT infants, but specific parenting styles can contribute to child difficulties and QOL in both infants and their mothers. CONCLUSION: We conclude that RFT has potential for understanding the conflicts experienced by parents caring for vulnerable children.

Adult↗
PubMed2005

The EPICure study: associations and antecedents of neurological and developmental disability at 30 months of age following extremely preterm birth.

AIMS: To describe perinatal factors associated with later morbidity among extremely preterm children at 30 months of age corrected for prematurity. POPULATION: Of 308 surviving children born at <or=25 weeks gestation in the United Kingdom and Ireland from March to December 1995, 283 (92%) were evaluated at 30 months of age corrected for prematurity. METHODS: Cerebral palsy, severe motor disability, and Bayley scores were used as dependent variables in sequential multiple regression analyses to identify factors associated with adverse outcomes. RESULTS: Adverse outcomes were consistently more common in boys. Factors related to perinatal illness, ultrasound evidence of brain injury, and treatment (particularly postnatal steroids) were associated with adverse motor outcomes (cerebral palsy, disability or Bayley psychomotor development index). Increasing duration of postnatal steroid treatment was associated with poor motor outcomes. A score was developed for severe motor disability with good negative predictive value. In contrast, mental development was associated with a broader range of factors: ethnic group, maternal educational level, the use of antenatal steroids, and prolonged rupture of membranes in addition to chronic lung disease. CONCLUSION: Male sex is a pervasive risk factor for poor outcome at extremely low gestations. Avoidable or effective treatment factors are identified, which may indicate the potential for improving outcome.

Cerebral Palsy↗
PubMed2003

The EPICure study: growth and associated problems in children born at 25 weeks of gestational age or less.

AIM: To define growth outcomes of a geographically defined population of extremely preterm babies. POPULATION: The EPICure study identified all surviving children in the United Kingdom and Ireland born at < or = 25 weeks 6 days gestation between March and December 1995. Of 308 survivors, 283 (92%) were evaluated at 30 months of age corrected for prematurity. METHODS: Growth was measured as part of a medical and full neurodevelopmental assessment. Growth parameters were evaluated in relation to other 30 month outcomes and perinatal variables. RESULTS: The children were smaller in each of the five growth measures compared with published population norms: mean (SD) standard deviation scores were -1.19 (1.32) for weight, -1.40 (1.37) for head circumference, -0.70 (1.19) for height, -1.00 (1.38) for body mass index, and -0.75 (0.95) for mid-upper arm circumference. Despite being of average size at birth, children were significantly lighter with smaller head circumferences at the expected date of delivery, compared with population norms, and only weight showed later catch up, by 0.5 SD. Poorer growth was found in children whose parents reported feeding problems and with longer duration of oxygen dependency, as a marker for neonatal respiratory illness. Although severe motor disability was associated with smaller head circumference, overall there was no relation between Bayley scores and head growth. CONCLUSIONS: Poor growth in early childhood is common in extremely preterm children, particularly when prolonged courses of systemic steroids have been given for chronic lung disease. Improving early growth must be a priority for clinical care.

Arm↗
PubMed2000

Neurologic and developmental disability after extremely preterm birth. EPICure Study Group.

BACKGROUND AND METHODS: Small studies show that many children born as extremely preterm infants have neurologic and developmental disabilities. We evaluated all children who were born at 25 or fewer completed weeks of gestation in the United Kingdom and Ireland from March through December 1995 at the time when they reached a median age of 30 months. Each child underwent a formal assessment by an independent examiner. Development was evaluated with use of the Bayley Scales of Infant Development, and neurologic function was assessed by a standardized examination. Disability and severe disability were defined by predetermined criteria. RESULTS: At a median age of 30 months, corrected for gestational age, 283 (92 percent) of the 308 surviving children were formally assessed. The mean (+/-SD) scores on the Bayley Mental and Psychomotor Developmental Indexes, referenced to a population mean of 100, were 84+/-12 and 87+/-13, respectively. Fifty-three children (19 percent) had severely delayed development (with scores more than 3 SD below the mean), and a further 32 children (11 percent) had scores from 2 SD to 3 SD below the mean. Twenty-eight children (10 percent) had severe neuromotor disability, 7 (2 percent) were blind or perceived light only, and 8 (3 percent) had hearing loss that was uncorrectable or required aids. Overall, 138 children had disability (49 percent; 95 percent confidence interval, 43 to 55 percent), including 64 who met the criteria for severe disability (23 percent; 95 percent confidence interval, 18 to 28 percent). When data from 17 assessments by local pediatricians were included, 155 of the 314 infants discharged (49 percent) had no disability. CONCLUSIONS: Severe disability is common among children born as extremely preterm infants.

Cohort Studies↗
PubMed2000

Neonatal and post-natal growth.

Growth velocity is higher in late intra-uterine and early post-natal life than at any time thereafter, and accurate measurements are essential for appropriate monitoring. The accuracy with which such measurements are made and recorded is frequently questionable, however, and short- and medium-term changes in growth may be difficult to interpret in the light of normal variations in the pattern of growth. Infants who are small at birth must be accurately classified because intra-uterine growth retardation and small for gestational age have different implications for both causation and outcome. Prediction of expected growth on the basis of mid-parental height is essential but frequently omitted. Post-natal growth impairment is common in pre-term infants and is often rapid in onset. Poor growth may continue for many months, and catch-up may be incomplete. Early growth failure may have a significant influence on subsequent morbidity and mortality.

Aging↗
PubMed2000

The EPICure study: outcomes to discharge from hospital for infants born at the threshold of viability.

OBJECTIVE: To evaluate the outcome for all infants born before 26 weeks of gestation in the United Kingdom and the Republic of Ireland. This report is of survival and complications up until discharge from hospital. METHODOLOGY: A prospective observational study of all births between March 1, 1995 and December 31, 1995 from 20 to 25 weeks of gestation. RESULTS: A total of 4004 births were recorded, and 811 infants were admitted for intensive care. Overall survival was 39% (n = 314). Male sex, no reported chorioamnionitis, no antenatal steroids, persistent bradycardia at 5 minutes, hypothermia, and high Clinical Risk Index for Babies (CRIB) score were all independently associated with death. Of the survivors, 17% had parenchymal cysts and/or hydrocephalus, 14% received treatment for retinopathy of prematurity (ROP), and 51% needed supplementary oxygen at the expected date of delivery. Failure to administer antenatal steroids and postnatal transfer for intensive care within 24 hours of birth were predictive of major scan abnormality; lower gestation was predictive of severe ROP, while being born to a black mother was protective. Being of lower gestation, male sex, tocolysis, low maternal age, neonatal hypothermia, a high CRIB score, and surfactant therapy were all predictive of oxygen dependency. Intensive care was provided in 137 units, only 8 of which had >5 survivors. There was no difference in survival between institutions when divided into quintiles based on their numbers of extremely preterm births or admissions. CONCLUSIONS: This study provides outcome data for this geographically defined cohort; survival and neonatal morbidity are consistent with previous data from the United Kingdom and facilitate comparison with other geographically based data.

Analysis of Variance↗
PubMed1998

Antioxidant activity, packed cell transfusions, and outcome in premature infants.

AIM: To evaluate the relative importance of biochemical markers of antioxidant status, gestational age, and parameters of neonatal care in the clinical outcome of premature infants. METHOD: A prospective, observational, longitudinal study of the association between these factors was conducted. Blood was collected from an in situ arterial line within two hours of birth and at intervals thereafter, when blood was drawn for routine clinical purposes. Outcome was assessed as death, or survival with or without bronchopulmonary dysplasia (BPD). One hundred and forty four babies of 22 to 39 weeks of gestation, who required intensive care at the Jessop Hospital for Women, between January 1993 and April 1994, were recruited. RESULTS: Low gestational age at birth was the most important predictor of mortality and the development of BPD. Having corrected for gestational age, low plasma antioxidant activity at birth was an independent risk factor for mortality. Plasma vitamin C at birth was significantly higher in the babies who died compared with those with a good outcome, but this effect was not sustained after correcting for gestational age. Repeated measures of Analysis of Variance revealed a postnatal increase in antioxidant activity, caeruloplasmin, retinol, cholesterol corrected alpha tocopherol, and red blood cell superoxide dismutase (SOD) activity. Vitamin C, on the other hand, declined in all groups after birth. Logistic regression analysis revealed that the greater the number of packed cell transfusions received during intensive care, and the higher the concentration of vitamin C on the second day of life, the greater the risk of developing BPD. CONCLUSIONS: After correcting for the effect of gestational age, low plasma antioxidant activity at birth was an independent risk factor for mortality. Frequent blood cell transfusions over the first week of life are associated with an increased risk of developing BPD. This association may be causal.

Antioxidants↗
PubMed1997

Imaging the neonatal chest.

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Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMed1997

Neonatal respiratory distress in near-term infants--consider surfactant protein B deficiency.

Two infants presenting with respiratory distress in the first 24 h of life are described. Both patients underwent extensive investigation before the diagnosis of surfactant protein B-deficiency was reached. Both children died within 2 months of birth. Parental consanguinity was known to be a feature in the first case, who proved to have a previously unrecognized mutation of the surfactant protein B gene. In the second case, a history of parental consanguinity was not sought from the Caucasian family, but was later volunteered by the parents themselves. Case 2 proved to have the "common" surfactant protein B-deficient genotype. The key to diagnosis is having a high index of suspicion in any term or near-term newborn with severe respiratory distress; parental consanguinity must be excluded. Surfactant protein B-deficiency can be readily diagnosed from bronchoalveolar lavage specimens; a simple, inexpensive procedure which is well tolerated in newborns.

Bronchoalveolar Lavage Fluid↗
PubMed1997

The measurement of neonates.

Accurate measurements of both healthy and premature neonates are possible but rarely performed. Routine anthropometry is often not performed at all or with large measurement errors due to inadequate training of personnel or inappropriate equipment. Sick neonates are often considered unsuitable for anthropometry and growth is wrongly equated with weight gain. Gain in length may be disturbed by poor health and permanent extrauterine growth retardation and changes in body proportions induced in some survivors of neonatal intensive care. Drug treatments may have profound effects on length gain and the relationship of length to weight.

Anthropometry↗
PubMed1995

Vitamin C at concentrations observed in premature babies inhibits the ferroxidase activity of caeruloplasmin.

High concentrations of total vitamin C have been measured in the plasma of premature infants. At these concentrations ascorbic acid inhibited the ferroxidase activity of caeruloplasmin measured directly in vitro. The degree of inhibition was dependent on the ratio of ascorbic acid: caeruloplasmin. Values for the ratio of vitamin C: caeruloplasmin measured in premature babies would be predicted to inhibit ferroxidase activity by up to at least 80%. Ferroxidase activity measured in the plasma of premature babies increased from birth but was significantly lower than in plasma collected from adults (< 0.001). Plasma ferroxidase activity was correlated with plasma caeruloplasmin concentration and, in premature babies only, showed a negative correlation with the ratio of vitamin C to caeruloplasmin. High levels of vitamin C in premature babies may compromise antioxidant mechanisms and exacerbate oxidant damage.

Antioxidants↗
PubMed1994

Early changes in lung function and response to surfactant replacement therapy.

Dynamic respiratory system compliance (Cdyn) was measured in 44 preterm babies before, immediately after, and for 96 h following administration of artificial surfactant (Exosurf). There was no significant change in Cdyn for the whole group over the entire study period. Subdivision into three groups on the basis of Cdyn prior to surfactant revealed a significant and sustained deterioration in lung function in those babies with the highest starting compliance and a significant and sustained improvement in those with the lowest compliance. Inspired oxygen and alveolar/arterial oxygen gradient also exhibited significant differences with least improvement in the babies with the best initial lung function and most improvement in the babies with worst initial lung function and most improvement in the babies with worst initial lung function. Despite clear initial differences in clinical status, neither long-term oxygen requirements nor the incidence of chronic lung disease differed significantly between the three groups. We conclude that the response of an individual baby to the administration of surfactant is, in part, determined by the lung function before surfactant is administered. Babies with higher initial lung compliance are more likely to deteriorate after administration and caution should be used before selection of such babies for surfactant treatment.

Humans↗
PubMed1994

High plasma vitamin C concentrations at birth associated with low antioxidant status and poor outcome in premature infants.

Concentrations of circulating antioxidants may be important in the aetiology of disease in premature infants. Blood samples were taken from 49 premature infants within two hours of birth. Plasma ascorbic acid, caeruloplasmin, and the ability of plasma to prevent lipid peroxidation in vitro were measured. Plasma ascorbic acid concentrations at birth ranged from 26.3 to 185.4 mumol/l. Plasma antioxidant activity at birth (microliter plasma required to inhibit lipid peroxidation) showed a strong negative correlation with plasma ascorbic acid and the plasma ascorbic acid to caeruloplasmin ratio. After correcting for gestational age and birth weight, plasma antioxidant activity at birth remained a significant predictor of mortality. Such plasma antioxidant activity is partly determined by the ferroxidase activity of caeruloplasmin. This may be modulated by high concentrations of ascorbic acid which may inhibit the antioxidant activity of plasma and thereby influence outcome.

Antioxidants↗
PubMed1994

Does vitamin C intake influence the rate of tyrosine catabolism in premature babies?

A study was conducted to investigate the relationship between vitamin C intake and the rate of tyrosine catabolism in premature babies. A 13C tyrosine breath test was developed for the measurement of tyrosine catabolism. Premature babies were randomly allocated to receive a daily intake of vitamin C which ranged from 8 to 100 mg/kg body weight, for 5 days. Tyrosine catabolism was measured at the beginning and the end of this period. Daily intakes of vitamin C of 20 mg/kg or more elicited a greater increase in tyrosine catabolism over 5 days than 8 mg/kg/day. The magnitude of the difference, in terms of percentage of tyrosine metabolised, was, however, small and of doubtful biological significance. Vitamin C intakes above 20 mg/kg/day had no further measurable effect on the catabolism of tyrosine.

Ascorbic Acid↗
PubMed1993

Knemometry and the assessment of growth in premature babies.

The characteristics of a knemometer designed for accurate lower leg measurement in babies were assessed. Repeated measurement of a 100 mm Perspex rod gave a mean length of 99.993 mm and a mean SD of 0.058. When used to measure leg length, technical error of the measurement technique was 0.31 with a mean leg length of 98.49 mm (coefficient of variation 0.31%). Leg lengths measured at birth in 324 babies from 23 to 42 weeks' gestation gave an estimated in utero leg length velocity of 0.43 mm/day (95% confidence interval 0.41 to 0.45). Assessment of interobserver variation showed poor agreement in absolute values of leg length, although similar estimates of leg length velocity could be obtained. The neonatal knemometer allows measurements to be made in situations where conventional growth measurements are not possible. It is believed that knemometry has an important role in accurate evaluation of factors that can influence short term bone growth.

Aging↗